Dissertations / Theses: 'Parasites'

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Grenier, Simon. "Biologie et physiologie des relations hôtes-parasitoïdes chez 3 tachinaires (Diptera, Tachinidae) d'intérêt agronomique : développement en milieux artificiels : lutte biologique." Lyon 1, 1986. http://www.theses.fr/1986LYO10004.

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Ferté, Hubert. "Les nématodes parasites du tube digestif du chevreuil (Capreolus capreolus L. 1758) : à propos d'une enquête réalisée dans le nord-est de la France." Tours, 1987. http://www.theses.fr/1987TOUR3805.

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Braga, Marta Isabel Fragoso Lampreia. "Prevalência e sazonalidade de parasitoses gastrointestinais, cardiovasculares e hemáticas em cães do distrito de Beja, Portugal." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2017. http://hdl.handle.net/10400.5/13687.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Os cães têm um importante papel na sociedade actual, contribuindo frequentemente para o desenvolvimento físico, social e emocional de crianças e para o bem-estar dos seus donos; contudo, podem ser portadores de muitas parasitoses, algumas com importância na saúde animal e potencial zoonótico. Este trabalho surge devido à escassez de dados epidemiológicos em cães na região Sul de Portugal, pretendendo estudar a prevalência e a sazonalidade de parasitoses gastrointestinais, cardiovasculares e hemáticas em cães de três canis do distrito de Beja: Canil Intermunicipal (CI), Canil Municipal de Ferreira do Alentejo (CF) e Associação Cantinho dos Animais de Beja (CA). Assim, de Março de 2015 a Fevereiro de 2016 foram colhidas 122 amostras fecais (AF) e 266 amostras sanguíneas (AS). As AF foram analisadas pelas técnicas de Flutuação de Willis, Sedimentação Natural, esfregaço fecal corado pelo método de Ziehl-Neelsen e contagem de ovos em câmara de McMaster. Nas AS realizaram-se as técnicas de Knott e de esfregaços corados pelo método de Giemsa e das Fosfatases Ácidas. Das AF 63% exibiam pelo menos um agente. Observou-se uma prevalência de 33% para Giardia spp., 25% para Ancylostomatidae, 12% para Cryptosporidium spp., 8% para Cystoisospora spp., 6% para Toxascaris leonina, 4% para Toxocara canis, 2,5% para Taeniidae, 2% para Trichuris vulpis. Das AS 74,3% apresentavam pelo menos um agente, registando-se 68% de amostras positivas para micoplasmas hemotrópicos (Mycoplasma spp.), 9% para Babesia spp., 5% para Dirofilaria immitis e 3% para Acantocheilonema spp. O canil com maior prevalência de parasitas gastrointestinais e amostras de sangue infectadas foi o CI, com prevalências de 87% e 86%, respectivamente. A estação do ano com maior prevalência de infecções foi o Inverno, com 81% das amostras fecais e 87% das amostras sanguíneas infectadas com pelo menos um agente. Este estudo mostra um elevado grau e diversidade de parasitismo na população de canídeos de Beja. De ressalvar que ambientes de canil conjugam características ideais para a infecção continuada por parasitas com ciclo de vida directo, alguns dos quais com potencial zoonótico. Torna-se por isso fundamental adoptar uma profilaxia dirigida e regular no controlo destas parasitoses, a fim de melhorar a saúde dos animais e diminuir os riscos para a Saúde Pública, e sensibilizar funcionários, voluntários e visitantes para a adopção de medidas que permitam quebrar o ciclo e evitar a transmissão destes agentes.
ABSTRACT - Prevalence and seasonal variation of gastrointestinal, cardiovascular and hematic parasites in dogs from Beja district, Portugal - Dogs have an important role in our society, contributing to the physical, social and emotional development of children and to the well-being of their owners; however, they may be carriers of many parasitic diseases, some of them with importance in Animal Health and with zoonotic potential. This study aimed to fulfil the lack of epidemiological data concerning dog parasites in the southern region of Portugal, namely on the prevalence and seasonal variation of gastrointestinal, cardiovascular and hematic parasites in dogs of three kennels from Beja district: Intermunicipal Kennel (CI), Municipal Kennel of Ferreira do Alentejo (CF) and Association Cantinho dos Animais from Beja (CA). Thus, from March 2015 to February 2016, 122 faecal samples (FS) and 266 blood samples (BS) were collected. FS were analyzed by Willis Flotation, Natural Sedimentation, Fecal Smear stained with Ziehl-Neelsen method and egg counting in McMaster's chamber. In BS Knott test and Smear stained with Giemsa and acid phosphatase histochemical stain were performed. Overall, 63% of the FS showed at least one agent. It was detected a prevalence of 33% for Giardia spp., 25% for Ancylostomatidae, 12% for Cryptosporidium spp., 8% for Cystoisospora spp., 6% for Toxascaris leonina, 4% for Toxocara canis, 2,5% for Taeniidae , 2% for Trichuris vulpis. In total, 74,3% of the BS were positive for at least one agent. It was observed a prevalence of 68% for hemotropic mycoplasmas (Mycoplasma spp.), 9% for Babesia spp., 5% for Dirofilaria immitis and 3% for Acantocheilonema spp. CI was the kennel with the highest prevalence of gastrointestinal parasites and positive blood samples, with prevalence of 87% and 86%, respectively. The season with the highest prevalence was the winter, with 81% of FS and 87% of BS positive for at least one agent. This study showed a high level and diversity of parasitism in dog’s population of Beja. It should be noted that kennel environment combine the ideal characteristics for the continuous infection by parasites with direct life cycle, some of them with zoonotic potential. It is, therefore, crucial to adopt a targeted and regular prophylaxis in the control of these parasites, in order to improve animal health and reduce the risk to Public Health, and also alert officials, volunteers and visitors of these kennels about measures to break the cycle and avoid the transmission of these agents.
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Schneider, Maria Victoria. "Modes de reproduction chez le parasitoi͏̈de solitaire Venturia canesces." Lyon 1, 2003. http://www.theses.fr/2003LYO10071.

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Venturia canescens, un parasitoi͏̈de ichneumonidé de chenilles de piralidés, a deux modes de reproduction : arrhénotoque, (mâles haploi͏̈des et femelles diploi͏̈des)) et thélytoque (des femelles vierges engendrent des filles diploi͏̈des). Cette thélytoquie n'est pas l'effet de bactéries symbiotiques. Dans le Sud de la France, les deux modes de reproduction coexistent en sympatrie. La thèse traite des questions soulevées par cette coexistence. Une étude de la distribution géographique et une analyse moléculaire des populations, ont montré l'existence d'un clone thélytoque très répandu. Cependant quelques individus thélytoques sont génétiquement très proches des individus arrhénotoques. Une importante partie de la variabilité chez les thélytoques est due à un flux génique à partir de mâles arrhénotoques. Pour mieux comprendre la coexistence des deux modes de reproduction, différents traits d'histoire de vie et compromis génétiques reflétants des différentes pressions de sélection ont été étudiés.

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Bell, Andrew Stuart. "Studies on the biosystematics and biology of strigeids (Digenea) parasitic in freshwater fish." Thesis, University of Stirling, 1995. http://hdl.handle.net/1893/3383.

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This study is concerned with two strigeid genera which utilise fish as their second intermediate host and piscivorous birds as a definitive host, i.e. Apatemon (Apatemon) Sudarikov, 1959 and Ichthyocotylurus Odening, 1969. Although the lifecycle has been ascertained for most Ichthyocotylurus spp., confusion and disagreement still exist as to the constituent species, while all of the life-stages have been described for only a single member of the subgenus Apatemon (Apatemon). In order to clarify species membership to these taxa and indeed the taxonomic position of the subgenus Apatemon (Apatemon) further information was required on the life-cycles and life-stages of these strigeids. Although, metacercariae from this family have been recorded from a variety of British fishes, confirmed records, i.e. those supported with life-cycle data, are limited to a single species. It was this lack of confidence in identifying metacercariae recovered from fishes and the lack of known good criteria for distinguishing the adults that prompted the present study. Collections of metacercariae from a variety of hosts and locations were made, from which all subsequent life-cycle stages were obtained. The project aims were to establish the identity of the forms occurring in British fishes, by applying discriminatory techniques to the experimentally reared life-stages. In addition to traditional methods, techniques with little previous application to these genera were used and included, scanning electron microscopy (SEM), chaetotaxy, principal components analysis (PCA), and karyology. Furthermore, behavioural aspects such as the release patterns of cercariae from their molluscan hosts were studied to investigate whether they would prove to be of diagnostic value. Metacercariae obtained from the sampling survey were tentatively identified, using all currently employed methods for their determination, i.e. morphology, nature of cyst, host and site specificities, as Ichthyocotylurus erraticus (Rudolphi, 1809), I. variegatus (Creplin, 1825), Apatemon gracilis (Rudolphi, 1819) and A. annuligerum (Nordmann, 1832). Material collected from Finland was considered to contain both Ichthyocotylurus spp. recovered in the U.K., as well as I. platycephalus (Creplin, 1825) and I. pileatus (Rudolphi, 1802). The Ichthyocotylurus spp. were found to be more host specific than A. gracilis, although A. annuligerum was considered oioxenic to perch Perea fluiatilis L. Records of I. erraticus from gwyniad Coregonus lavaretus (L.) and grayling Thymallus thymallus (L.), and A. gracilis from arctic charr Salvelinus alpinus (L.) constitute first listings from Britain. The large number of sensilla present on the body surface of these metacercariae, observed by SEM and chaetotaxy, precluded their diagnostic use. PCA was, however, found to be of value for distinguishing between species and determining morphological variation within a species. I. erraticus, I. variegatus and A. gracilis adults were successfully reared in experimental hosts using metacercariae from a variety of fish hosts, sites within a single fish host and geographical sites. The adults obtained enabled clarification of the identities assigned to the metacercariae. Those metacercariae believed to represent I. pileatus and A. annuligerum failed to establish in experimental hosts. Herring gulls and lesser black-backed gulls proved to be extremely good experimental hosts for both Ichthyocotylurus spp., with the vast majority of infections establishing and providing high yields of eggs and adults. These infections yielded information on the establishment, development, fecundity, site specificity, longevity and morphological variability of the adults. Aspects of the morphology and biology of I. variegatus adults recorded were found to support its validity as a species discrete from I. platycephalus which was in some doubt. The experimental hosts used for A. gracilis infections, domestic and mallard ducklings, were found to be less satisfactory. Challenges were performed with A. gracilis metacercariae from three sources, rainbow trout, salmon parr and stone loach. The latter source was the only one to result in egg producing adults, with specimens exhibiting normal morphology and demonstrating an increased longevity over adults raised from salmonid metacercariae. These findings suggest that the metacercarial host may affect the successful completion of the life-cycle. Eggs of known origin were collected for all three cultured strigeid species, enabling further life-cycle studies, these were incubated and miracidia successfully raised. Developmental periods were found to be temperature dependent and differed for the three species at 20°C: A. gracilis < I. erraticus < I. variegatus. Light microscopy revealed the morphology of all three species to be identical, as were the epidermal plate formulae and chaetotaxy, indicated by silver-staining. The nomenclature for the distribution of miracidial sensilla derived by Dimitrov et al. (1989) was amended to enable a full description of these species. Osmotic shock resulted in an improved deciliation of the miracidia compared to sonication and subsequent SEM observation confirmed the arrangement of body surface structures, while revealing sensilla forms. Behavioural aspects of I. variegatus miracidia were examined, with a maximum longevity (< 11 hours) recorded at the lowest temperature studied (l0 degrees C), and host finding demonstrated to occur by an increased turning response in the presence of substances emitted from the susceptible snail host, following an initial unresponsive dispersal phase. Ichthyocotylurus cercariae were found in naturally infected Valvata piscinalis which constitutes the first record in Britain of cercariae of this genus. Cercariae of I. erraticus and I. variegatus were successfully raised experimentally from miracidia of known identity and origin within naive, experimentally raised V. piscinalis hosts, while A. gracilis cercariae were obtained from laboratory reared Lymnaea peregra. Cercarial developmental periods within the molluscan host were found to be temperature dependent and markedly different for the strigeid genera investigated, as were their behaviour and morphology. The Ichthyocotylurus spp. exhibit a distinct diurnal emergence rhythm from their molluscan host, being shed during the hours of daylight, while A. gracilis cercariae demonstrate a reciprocal pattern, emerging during the hours of darkness. Behavioural contrasts were also observed in longevities, emergence strategies (route of exit) and swimming behaviour. The two Ichthyocotylurus spp. were extremely similar, the only cercarial features found to be of diagnostic use were: the presence or absence of eye-spots; their differing developmental periods from miracidium to cercaria; the number and distribution of sensilla when compared by PCA; and their differing longevities at 20 degrees C. Characters considered to be of value in differentiating between strigeid cercariae at the species level, including the armature, chaetotaxy pattern and resting posture, did not differ between these two species. SEM observations enabled descriptions of the variety and structure of sensilla present on different life-stages, while transmission electron microscopy revealed the internal structure of cercarial sensory structures. Experimentally raised cercariae were found to be infective and the life-cycle was completed for the three strigeid species. Host specificities were observed for I. erraticus and A. gracilis, being particularly stringent for the latter species, while site specificities recorded were as observed in natural infections. Metacercarial maturation periods (for encystment) were highly temperature dependent, being comparable for the two Ichthyocotylurus spp. and more rapid than for A. gracilis specimens.

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Mintsa, Nguema Rodrigue. "Interactions hôte-parasite dans le modèle Biomphalaria pfeifferi-Schistosoma mansoni du Dhofar (Oman) : génétique des populations de l’hôte, traits d’histoire de vie et conséquences sur la transmission du parasite." Perpignan, 2010. http://www.theses.fr/2010PERP0995.

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Cette thèse a été réalisée dans le contexte de la réémergence de la schistosomose à Schistosoma mansoni (plathelminthe trématode) dans le Dhofar en Oman. Le travail est centré sur les interactions hôte-parasite et sur leurs conséquences sur la transmission du schistosome. Une première partie est consacrée à l’étude spatio-temporelle de la structure génétique des populations de Biomphalaria pfeifferi (mollusque gastéropode d’eau douce). Elle a été réalisée à l’aide de neuf marqueurs microsatellites sur 18 populations de mollusques. Les populations de B. Pfeifferi étudiées sont caractérisées par une très faible variabilité génétique intra populationnelle. Par contre, elles sont fortement différenciées génétiquement. Une différenciation temporelle a également été enregistrée dans certaines populations. Une seconde partie est consacrée à l’étude des traits d’histoire de vie et des relations hôte-parasite. Elle a été réalisée à l’aide de huit combinaisons hôte-parasite qui diffèrent soit par la population de parasite (origine humaine ou origine murine), soit par la catégorie du site (naturel ou aménagé), soit par le morphe du mollusque (pigmenté ou albinos). Les traits d’histoire de vie suivants ont été analysés : croissance, fécondité et survie de B. Pfeifferi et taux d’infestation, période prépatente et production cercarienne de S. Mansoni. Les résultats montrent que la population de S. Mansoni et le morphe de B. Pfeifferi jouent un rôle majeur dans la transmission de la schistosomose dans le Dhofar. Les résultats sont discutés en termes de compatibilité hôte-parasite
This thesis has been conducted in the context of the reemergence of schistosomiasis caused by Schistosoma mansoni (flatworm trematode) in Dhofar (Oman). The work focuses on the host-parasite interactions and their implications on schistosome transmission. The first part is devoted to a spatiotemporal study of the population genetics of Biomphalaria pfeifferi (freshwater gastropod snail). Nine microsatellite markers were used for characterization of 18 populations of B. Pfeifferi. The results showed that intrapopulations genetic variability was very low. However, the populations were highly differentiated. Temporal differentiation was also recorded in some populations. A second part concerns to the study of the life-history traits and host-parasite relationships. It was conducted using eight host-parasite combinations that differ either by the parasite population (human versus murine), by the waterbody category (natural versus man-made) or by the morph of the snail (pigmented versus albino). The following life-history traits were analyzed: growth, fecundity and survival of B. Pfeifferi and rate of infection, prepatent period and cercarial production of S. Mansoni. The results show that both the origin of S. Mansoni and the pigmentation of B. Pfeifferi play a major role in transmission of schistosomiasis in Dhofar. The results are discussed in terms of host-parasite compatibility

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Owen, Sinclair Patrick. "The first epidemiological study on the prevalence of cardiopulmonary and gastrointestinal parasites in cats and dogs from the Algarve region of Portugal using the FLOTAC technique." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2017. http://hdl.handle.net/10400.5/14521.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Although over the past decades various parasitologal surveys have been conducted in Portugal, at present scant information is available on the prevalence of clinically-relevant gastrointestinal and cardiopulmonary parasites in the Algarve. This study performed between February and April 2016 using the FLOTAC technique was undertaken to address this. Faecal samples were collected from 66 dogs and 76 cats > 6 months old from shelters in the region. Faecal forms of six different groups of endoparasites were detected, four of which with zoonotic potential. The overall prevalence in both species was 31%, with 21.2% of the dog samples positive and 39.5% of the cat samples positive for at least one parasite. Concurrent infections with two parasites were detected in 2.6% of the dog samples and 9.2% of the cats. Toxocara spp. was the most common parasite found in 13.6% (EPG: 61.3 ± 74.65) of the dogs samples and 31.6% (EPG 523.92 ± 688.75) of the cats. Other parasites found in dogs were Ancylostomatidae (3%), Taeniidae (6%) and Trichuris spp. (2%) and in cats Ancylostomatidae (5.3%), Aelurostrongylus abstrusus (4%), Cystoisospora spp. (6.6%) and Taeniidae (1.3%) were found. The presence of zoonotic parasites in the population studied as well as the elevated prevalence of Toxocara spp. overall are concerning and highlight the need for regular prophylaxis, hygiene and sanitary control measures in pets as well as shelter animals.
RESUMO - PRIMEIRO RASTREIO DE PARASITAS CARDIOPULMONARES E GASTROINTESTINAIS EM CÂES E GATOS DA REGIÂO DO ALGARVE UTILIZANDO A TÉCNICA DE FLOTAC - Apesar de nas últimas décadas terem surgido vários trabalhos de rastreio parasitológico em Portugal, atualmente continuam a existir poucos dados sobre a incidência de parasitas gastrointestinais e cardiopulmonares de carnívoros domésticos com relevância clinica no Algarve. Por esta razão foi realizado um estudo entre Fevereiro e Abril de 2016 utilizando a técnica do FLOTAC. No total foram colhidas 142 amostras de canis e gatis da região correspondendo a 66 cães e 76 gatos todos com > 6 meses de idade. Foram detetadas formas de eliminação fecal de seis grupos de endoparasitas, quatro dos quais com potencial zoonótico. A prevalência global no estudo foi de 31%, com 21.2% das amostras de canídeo positivas e 39.5% de felídeo positivos para pelo menos um parasita. Infeções mistas com dois parasitas foram observadas em 2.6% das amostras de cão e 9.2% das de gato. Toxocara sp. foi o parasita mais frequente em cães evidenciando-se em 13.6% (OPG: 61.3 ± 74.65) das amostras e em 31.6% (OPG 523.92 ± 688.75) das de gato. Nos cães também foram detetadas amostras positivas para Ancylostomatidae (3%), Taeniidae (6%) e Trichuris spp. (2%) e nos gatos Ancylostomatidae (5.3%), Aelurostrongylus abstrusus (4%), Cystoisospora spp. (6.6%) e Taeniidae (1.3%). A presença de parasitas com potencial zoonótico na população estudada bem como e elevada prevalência de Toxocara spp. é preocupante e alerta para a necessidade de desparasitação regular e medidas de controlo higio-sanitário adequadas, quer em animais com proprietário, quer em animais de abrigo.
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Isomursu, M. (Marja). "Host–parasite interactions of boreal forest grouse and their intestinal helminth parasites." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526203645.

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Abstract Parasites are an inseparable part of the life of wild birds. They may cause morbidity, mortality or reduction in fecundity. Parasite distribution in hosts is typically not uniform and many host factors (e.g. age) may affect the pattern of distribution. Under certain conditions, parasites even have the potential to regulate the host population. The grouse species of Finnish forests — the capercaillie Tetrao urogallus , the black grouse Lyrurus tetrix and the hazel grouse Tetrastes bonasia — harbour several species of intestinal helminth parasites. The populations have fluctuated in cyclic manner but the mechanisms behind the cycles are largely unknown. I studied the interactions of forest grouse and their intestinal helminth parasites by using intestinal samples collected by hunters in five game management districts during eight years (1995–2002). The most common parasite species in the samples was the nematode Ascaridia compar. Also, three species of cestodes (Skrjabinia cesticillus, Paroniella urogalli and Hymenolepis sp.) were found. Large size, male gender and age over 1 year were connected with an increased probability and intensity of A. compar infection. Juvenile grouse were commonly infected with cestodes while in adults infections were quite rare. The influence of inbreeding on the susceptibility to parasite infections was studied in the capercaillie by analysing microsatellite heterozygosity. The less heterozygous birds were more likely to be infected with A. compar and were more intensely infected suggesting negative influence of inbreeding on parasite resistance. An indirect negative effect of parasites was found by comparing bags hunted with a trained dog or without a dog. Grouse infected by cestodes were significantly more common in the dog-assisted bag. Thus, cestode infection seemed to make grouse more vulnerable to canine predation. The interaction between grouse population dynamics and parasites was studied by analyzing the grouse densities obtained from annual wildlife counts and parasite indices. A. compar was most common and most abundant in the years of grouse population decline. The grouse population growth rate was negatively correlated with the annual mean abundance of A. compar. Relative survival but not breeding success decreased as the abundance of A. compar increased. The findings suggest that A. compar influences the dynamics of Finnish grouse even though regular cyclic dynamics are no longer evident
Tiivistelmä Loiset kuuluvat erottamattomana osana luonnonvaraisten lintujen elämään. Ne voivat aiheuttaa sairautta, kuolleisuutta tai hedelmällisyyden alentumista. Tyypillisesti loiset ovat levinneet isäntäpopulaatioon epätasaisesti ja monet isännän ominaisuudet (esim. ikä) vaikuttavat levinneisyyteen. Tietyissä oloissa loiset voivat jopa säädellä isäntäpopulaatiotaan. Suomalaiset metsäkanalinnut — metso Tetrao urogallus, teeri Lyrurus tetrix ja pyy Tetrastes bonasia — ovat useiden suolistoloismatolajien isäntiä. Metsäkanapopulaatiot ovat vaihdelleet syklisesti, mutta syklejä aiheuttavat mekanismit ovat yhä tuntemattomia. Tutkin metsäkanalintujen ja niiden suolistoloisten välisiä vuorovaikutuksia käyttäen metsästäjien vuosina 1995–2002 viidestä eri riistanhoitopiiristä keräämiä suolistonäytteitä. Yleisin loislaji näytteissä oli kanalintusuolinkainen, Ascaridia compar. Myös kolme heisimatolajia (Skrjabinia cesticillus, Paroniella urogalli ja Hymenolepis sp.) todettiin. Suuri koko, koirassukupuoli ja yli yhden vuoden ikä olivat yhteydessä suurempaan kanalintusuolinkaistartunnan todennäköisyyteen ja voimakkuuteen. Nuorilla (alle 1 v.) linnuilla heisimadot olivat yleisiä, kun taas aikuisilla tartunnat olivat varsin harvinaisia. Sisäsiittoisuuden vaikutusta loistartuntaherkkyyteen tutkittiin metsolla mikrosatelliittiheterotsygotian perusteella. Vähemmän heterotsygoottiset metsot olivat todennäköisemmin ja voimakkaammin suolinkaisten infektoimia, mikä viittaa sisäsiittoisuuden negatiiviseen vaikutukseen loisten vastustuskykyyn. Loisten epäsuora haitallinen vaikutus havaittiin, kun verrattiin koiran kanssa ja ilman koiraa metsästettyä lintusaalista. Heisimadot olivat selvästi yleisempiä linnuilla, jotka oli metsästetty koiran kanssa kuin ilman koiraa metsästetyillä. Heisimatotartunta näytti siis altistavan metsäkanoja koiraeläinten saalistukselle. Metsäkanalintu- ja loispopulaatioiden välistä vuorovaikutusta tutkittiin analysoimalla vuosittaisia metsäkanatiheyksiä ja loisten runsautta. Kanalintusuolinkainen oli yleisimmillään ja runsaimmillaan metsäkanatiheyden laskuvuosina. Metsäkanapopulaation vuosittainen kasvuvauhti korreloi negatiivisesti kanalintusuolinkaisen vuosittaisen runsauden kanssa. Suhteellinen elossasäilyvyys laski kanalintusuolinkaisen runsauden lisääntyessä, mutta lisääntymistuloksen suhteen ei ollut samaa ilmiötä. Löydökset viittaavat siihen, että kanalintusuolinkaisella on vaikutusta suomalaisten metsäkanalintukantojen vaihteluihin, vaikka syklisiä kannanvaihteluja ei enää havaitakaan

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St, Vincent Chad Michael. "'Parasite single' women of Japan : 'parasites' or search for a new identity? /." Title page, contents and introduction only, 2002. http://web4.library.adelaide.edu.au/theses/09AR/09ars7749.pdf.

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Goodhead, Ian Barry. "Genomic approaches to understanding host resistance and parasite virulence in Trypanosoma parasites." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.570185.

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Roughly one-third of cattle in sub-Saharan Africa are at risk of contracting "Nagana" - a disease caused by Trypanosoma parasites similar to those that cause human "Sleeping Sickness". Laboratory mice can also be infected by trypanosomes, and different mouse breeds show varying levels of susceptibility to infection, similar to what is seen between breeds of cattle. We have applied next-generation technologies to identify shared polymorphisms between susceptible mice, and annotated these for potential function alongside publicly available SNP data sets. By so doing, short lists of genes at the QTL have been created to aid functional testing in cattle. This includes two promising 'candidate genes': Pram1 and Cd244, which can now be tested to confirm their effect on response to trypanosome infection. The human-infective parasite Trypanosoma brucei rhodesiense generally causes an acute form of "sleeping sickness" across Eastern Africa, compared to the more chronic T b. gambiense infections found in Western Africa. The 1988-1993 Ugandan T b. rhodesiense outbreak constituted infections by parasites with differences in their clinical manifestation. Two such sub types, termed Busoga 17 (B 17) and Zambesi 310 (Z31O), caused more acute, and more chronic infections, respectively. In order to investigate whether the major QTL that regulates survival in T congolense infections (Tir 1) does so in a similar manner in T b. rhodesiense, mice congenic for the C5 7BL/ 6 allele (Tirl CC) at Tir 1 were infected with Z310 and B 1 7 zymodeme T b. rhodesiense parasites. Whilst Tir 1 was not found to have a significant effect on survival, all mice had a significantly shorter mean survival time when infected with B 17 (~1O. 7 days) than those infected with Z31 0 (~15.6 days), in line with previous observations of human infections. In order to identify genetic loci that might underlie differences in virulence between T b. rhodesiense zymodemes, cluster analysis was performed on the microsatellite genotypes of 31 T b. rhodesiense isolates that represented nine different zymodemes. Despite STRUCTURE identifying three population clusters, the Z310 and B 17 parasite populations could not be distinguished, suggesting that either multiple genes control virulence, that there is gene flow between similar parasite populations, or that the microsatellite genotyping is insufficient to distinguish between different parasite populations. Finally, we present the first whole-genome sequences of T b. rhodesiense field isolates, one each of Z310 and B 1 7. Genomic analysis of east African T b. rhodesiense and west African T b. gambiense has suggested that recombination may be occurring between them. SNP genotyping of 32 T b. rhodesiense isolates showed that differences in clinical phenotypes were associated with differences in alleles on chromosome 8. The genome sequence suggests that chromosome 8 is heterozygous for alleles of west African origin in the more virulent strain, suggesting that recombination may be associated with parasite virulence. This suggests that the human subspecies of T brucei are not genetically distinct, which has major implications for the control of the parasite, the spread of drug resistance and understanding the variation in virulence and the emergence of human infectivity. Further genetic analysis of T b. brucei populations from Western, central and Eastern Africa may be necessary to ascertain whether recombination is occurring directly between human-infective subspecies, or in the underlying animal-infective population.

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Fregonesi, Brisa Maria. "Prevalência de parasitas emergentes e reermergentes de veiculação hídrica em crianças que vivem com HIV/aids: ênfase paraGiardia spp. e Cryptosporidium spp." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/22/22133/tde-22012014-104630/.

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As doenças de veiculação hídrica são causadas, principalmente, por micro-organismos patogênicos de origem entérica. A partir da década de 1980, as enfermidades causadas por protozoários parasitas emergiram e reemergiram e se tornaram um problema de saúde pública com relevância na atualidade, especialmente para grupos populacionais mais vulneráveis, como pessoas que vivem com HIV/aids. Este trabalho teve por objetivo avaliar a prevalência de parasitas emergentes e reemergentes em crianças que vivem com HIV/aids atendidas no HCFMRP-USP e os condicionantes socioambientais envolvidos. Foram coletadas 47 amostras de fezes de 17 crianças de quatro a 13 anos que vivem com HIV/aids atendidas no HCFMRP- USP, no período de março a setembro de 2013. Do total, 52,9% das crianças eram do sexo feminino e 47,1% do sexo masculino, sendo que 52.9% eram pardas, 35,3% brancas e 11,8% negras. A análise de coccídeos intestinais oportunistas, como Cryptosporidium spp., Cyclospora spp. e Cystoisospora spp. foi realizada pelo método de Ziehl Nielsen Modificado, enquanto que para a pesquisa de cistos de Giardia spp. e outros parasitas foi utilizado o método de sedimentação espontânea por meio do Kit Coproplus®. As presenças dos parasitas Giardia spp e Cryptosporidium spp. foram confirmadas por meio de ensaios imunoenzimáticos para detecção de antígenos (métodos de Elisa). Foi ainda aplicado um questionário referente às questões socioambientais, hábitos comportamentais e hábitos de higiene pessoal e alimentar adotados pelas crianças participantes do estudo e algumas informações adicionais foram coletadas dos prontuários. Os resultados obtidos revelaram uma alta frequência de parasitas em crianças que vivem com HIV/aids atendidas no HCFMRP- USP (76,5%), sendo representados por agentes patogênicos: Giardia spp. (35,3%), Cryptosporidium spp. (23,5%), Cyclospora spp. (5,9%); e agente comensal: Entamoeba coli (47,1%). Apesar de se tratar de protozoários de veiculação hídrica, considera-se que a água utilizada pelas crianças não seja a principal via de transmissão desses parasitas, tendo em vista as evidencias que existem da boa qualidade da água que abastece a região, procedente do Aquífero Guarani. Dessa forma, considera-se que as características socioambientais, os hábitos de higiene pessoal e alimentar adotados pelas crianças bem como o contato com outras pessoas e/ou animais podem ter contribuído para o quadro de enteroparasitoses. A alta prevalência de parasitas encontrada no presente estudo nos remete a grandes preocupações em termos de saúde pública, uma vez que, o quadro clínico para Giardia spp., Cryptosporidium spp, Cyclospora spp. pode evoluir para uma morbidade grave quando há uma supressão do sistema imunológico do indivíduo. Dessa forma, conclui-se que alguns aspectos são imprescindíveis para uma melhoria da qualidade de vida das crianças que vivem com HIV/aids, dentre os que se destacam: o diagnóstico precoce para enteroparasitas, a implementação da análise coprológica de protozoários emergentes e reemergentes na rotina da atenção desses pacientes, o uso correto da terapia antirretroviral, bem como o monitoramento das características imunológicas
The waterborne diseases are caused mainly by pathogenic microorganisms enteric origin. From the 1980s, the diseases caused by protozoan parasites emerged and re-emerged and have become a public health problem of relevance today, especially for the most vulnerable population groups such as people living with HIV/aids. This study objetived to assess the prevalence of emerging and re-emerging parasites in children living with HIV/aids followed at HCFMRP-USP and socioenvironmental constraints involved. Were collected 47 stool samples from 17 children aged four to 13 years living with HIV/aids followed at HCFMRP- USP, in the period from March to September 2013. Of the total, 52.9% of children were female and 47.1% male, and that 52.9% were brown, 35.3% white and 11.8% black. The analysis of intestinal coccidia opportunistic as Cryptosporidium spp. Cyclospora spp. and Cystoisospora spp. was performed by the modified Ziehl Nielsen method, while for the research of Giardia spp. and other parasites was used by spontaneous sedimentation method by means of Kit Coproplus®. The presence of Giardia spp and Cryptosporidium spp. were confirmed by enzyme immunoassays for the detection of antigens (ELISA methods). Was still applied a questionnaire relating to socioenvironmental issues, behavioral habits and personal hygiene habits and food adopted by the children participating in the study and some additional information was collected from medical records of children. The results revealed a high frequency of parasites in children living with HIV/aids followed at HCFMRP-USP (76.5%), being represented by pathogens: Giardia spp. (35.3%), Cryptosporidium spp. (23.5%), Cyclospora spp. (5.9%), and commensal agent: Entamoeba coli (47.1%). Although it being waterborne protozoa, is considered that the water used by children is not the main route of transmission of these parasites, in view of the evidence that there are good-quality water that supplies the region, coming from the Guarani Aquifer. Thus, it is considered that the socioenvironmental characteristics, personal hygiene and food adopted by children as well as contact with other people and / or animals may have contributed to the enteroparasitosis frame. The high prevalence of parasites found in this study leads us to great concern in terms of public health, since the clinical picture for Giardia spp., Cryptosporidium spp. e Cyclospora spp. may progress to severe morbidity when there is a suppression of the immune system of the individual. Thus, it is concluded that some aspects are essential to improving the quality of life for children living with HIV/aids, among which stand out: early diagnosis for intestinal parasites, the implementation of coprologic analysis of emerging and reemerging protozoan in routine care of these patients, the correct use of antiretroviral therapy, as well as monitoring of the immunological characteristics

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Houngbédji, Tossimidé. "Rhamphicarpa fistulosa : infestation dans les bas-fonds rizicoles de la Région des Savanes (Togo) et étude des interactions hôte-parasite." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS455/document.

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Une des contraintes biotiques majeures de la riziculture de bas-fond au nord du Togo est l’adventice parasite Rhamphicarpa fistulosa (Hochst.) Benth. Afin d’évaluer les options stratégiques pour contrôler efficacement R. fistulosa, notre étude a été conduite avec comme principaux objectifs : 1) l’identification de la répartition de R. fistulosa et l’étude des facteurs qui favorisent son infestation, 2) l’étude de l’impact des niveaux d’infestation sur la flore adventice du riz, et 3) la caractérisation des interactions hôte-parasite et de leurs impacts sur le développement de l’hôte et les performances reproductives du parasite. A l’issu des prospections de terrain, les plus fortes infestations ont été retrouvées sur des sols majoritairement à texture sableuse et très pauvres en matière organique. Une flore adventice très diversifiée a été retrouvée en présence de R. fistulosa, certaines adventices pouvant être parasitées et constituer éventuellement un réservoir pour accroître le stock semencier du parasite. En conditions contrôlées, R. fistulosa se développe et se reproduit aussi bien sur le riz que sur la tomate, alors que le soja retarde la reproduction du parasite. La germination des graines de R. fistulosa est maximale en présence de graines de plantes cultivées ou adventices. Les graines nouvellement récoltées ont une dormance de plus de six mois, mais leur germination a été stimulée par la présence de phytohormones. En conclusion, les meilleures stratégies de lutte doivent impliquer le contrôle par les semis tardifs, les rotations culturales avec les légumineuses comme le soja, l’arachide ou le niébé, et les cultures maraîchères
Main biotic constraints to rain-fed lowland rice cultivation in northern Togo include the parasitic weed Rhamphicarpa fistulosa (Hochst.) Benth. In order to evaluate efficient strategies to control R. fistulosa, our study was performed taking into account the following main objectives: 1) Identification of the distribution of R. fistulosa and study of the factors favouring its infestation, 2) Study of the impacts of infestation levels on rice weed communities, and 3) Characterization of the host-parasite interactions and their impacts on the host development and the parasite reproduction. Following fields investigations, highest infestations were observed on sandy soils with low levels of organic matter.In addition, weed flora found in the presence of R. fistulosa was much diversified and some weeds were found to been parasitized and could possibly constitute reservoirs to increase the seed stock of the parasite. In controlled experiments, R. fistulosa grown and reproduced better on rice and tomato crops, than on soybean which delayed the reproduction of the parasite. Germination of R. fistulosa seeds was stimulated in presence of cultivated crops or weeds. New collected seeds shown six months dormancy but their germination was stimulated in presence of phytohormones. In conclusion, the best strategies to control R. fistulosa must include delayed sowing, crop rotation with leguminous species (i.e. soybean, peanut or cowpea) and vegetable cropsKeywords: Rhamphicarpa fistulosa, rice, lowland, parasitism, host-parasite interaction, weeds

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Le, Brun Nathalie. "Spécificité des relations hôtes-parasites : le modèle Cyprinidae-Diplozoon." Montpellier 2, 1988. http://www.theses.fr/1988MON20055.

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La spécificité parasitaire est abordée à travers les modèles fournis par 4 espèces du genre Diplozoon, parasite branchial de Cypirindae. Plusieurs populations de Diplozoon sont étudiées et comparées dans le sud de la France et en Suisse (lac de Neuchatel)

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browne, Joanna. "Parasites of Jellyfish in Eastern Australia." Thesis, Griffith University, 2015. http://hdl.handle.net/10072/367791.

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Parasites are a major component of the Earth’s biota, yet are often overlooked and their importance underestimated. They affect nearly all organisms and can potentially regulate the populations of their hosts. Jellyfish are abundant members of the zooplankton community and are renowned for their ability to form large blooms. Jellyfish host a large diversity of parasites. Some of these parasites (e.g. hyperiid amphipods and parasitic anemones) use jellyfish as the sole host in their life cycle, whilst others (e.g. digenean trematodes and cestodes) use jellyfish as an intermediate host between other host organisms. There have been few ecological studies of jellyfish parasites (for example of spatial and temporal variation in parasite-host relationships) relative to other aspects of jellyfish biology. This may be partly attributable to the very small size of some parasites (e.g. digenean trematodes) and also to difficulties such as identifying larval parasite forms. However, with the advent of new technologies, such as molecular identification, and with diligent examination, these difficulties are able to be overcome. This thesis aims to identify jellyfish parasites using molecular and morphological techniques and elucidate their life cycles, examine spatial and temporal variation in jellyfish parasites and investigate the diversity and host specificity of the parasites of jellyfish in eastern Australia.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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15

Carvalho, Íris Teixeira. "Rastreio de parasitas gastrointestinais e pulmonares em gatos de gatis nos distritos de Lisboa e Setúbal, Portugal." Master's thesis, Universidade de Lisboa, Faculdade de Medicina Veterinária, 2017. http://hdl.handle.net/10400.5/13937.

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Dissertação de Mestrado Integrado em Medicina Veterinária
Os gatos são hospedeiros de diversos parasitas, sendo reconhecido o potencial zoonótico de alguns. O risco de transmissão aos humanos assumiu particular relevância nos últimos anos, devido à crescente popularidade do gato como animal de estimação. No entanto, são raros os estudos efetuados em Portugal sobre este tema, motivo pelo qual se procedeu a uma avaliação epidemiológica da fauna parasitológica gastrointestinal e pulmonar, em gatos mantidos em gatis, nos distritos de Lisboa e Setúbal. Para o efeito, recolheram-se 260 amostras fecais distribuídas por ambos os distritos entre Julho e Novembro de 2015, sendo 169 provenientes de Lisboa e 91 de Setúbal. Foram submetidas a análise através de quatro técnicas coprológicas qualitativas: Flutuação de Willis, Sedimentação Natural, Método de Baermann e Esfregaço fecal. Foi ainda realizada uma pesquisa de Tritrichomonas foetus em 25 gatos através do meio de cultura InPouchTM TF-Feline. Observaram-se formas parasitárias em 43,5% das amostras (113/260), tendo sido detetadas infeções mistas em 18,1% (47/260) dos casos. O grupo predominante de parasitas foi a dos Protozoários (34,6%), seguido dos Nemátodes (33,8%) e Céstodes (1,5%). O nemátode Toxocara cati foi identificado em 18,1% das amostras, (47/260), correspondendo à maior prevalência, seguido de Cystoisospora felis identificado em 16,9% (44/260), Cystoisospora rivolta 11,2% (29/260), Ancylostomatidae 10,4% (27/260), Aelurostrongylus abstrusus 5,4% (14/259), Cryptosporidium spp. 4,4% (9/204), Giardia spp. 3,9% (8/204), Taeniidae 1,2% (3/260) e Dipylidium caninum 0,4% (1/260). Não foram detetadas formas parasitárias de T. foetus. Os resultados comprovaram o elevado grau de parasitismo nos gatis estudados, em particular dos agentes zoonóticos das famílias Toxocaridae, Ancylostomatidae, Taeniidae e dos géneros potencialmente zoonóticos Cryptosporidium e Giardia. O número excessivo de animais nos gatis e consequente elevada proximidade, facilita a transmissão de parasitas com ciclos de vida diretos, o que pode justificar os resultados encontrados para T. cati e Cystoisospora spp. A dependência financeira dos gatis dificulta a pronta e eficaz implementação de atitudes profiláticas e de controlo, tornando mais difícil a erradicação de parasitoses. Espera-se que a crescente sensibilização a nível da sociedade, favorecendo a Saúde e Bem-Estar Animal, com repercussão jurídica e política, possa de algum modo disponibilizar meios e melhores condições nos gatis.
ABSTRACT - GASTROINTESTINAL AND LUNG PARASITES SURVEY IN SHELTER CATS FROM LISBON AND SETÚBAL DISTRICTS, PORTUGAL - Cats host numerous parasites, some of which are responsible for important zoonoses. Moreover, the increasing popularity of cats as companion animals may increase the risk of transmission of these agents to humans. Nevertheless, in Portugal few studies have been conducted to address this subject. Therefore, an epidemiological survey was performed to assess the prevalence of gastrointestinal and lung parasites among shelter cats from Lisbon and Setúbal districts, two main highly populated urban areas in Portugal. Between July and November 2015, 260 faecal samples were randomly collected and analysed using qualitative coprological techniques: Willis flotation, natural sedimentation, faecal smear and Baermann technique. Additionally, it was conducted a Tritrichomonas foetus survey in 25 cats using InPouchTM TF-Feline culture method. Overall, 43.5% (113/260) of the samples were positive for parasitic agents and 18.1% (47/260) showed co-infections. Protozoa was the most prevalent group (34.6%), followed by nematodes (33.8%) and cestodes (1.5%). The genera/species detected were Toxocara cati with 18.1% (47/260), followed by Cystoisospora felis 16.9% (44/260), Cystoisospora rivolta 11.2% (29/260), Ancylostomatidae 10.4% (27/260), Aelurostrongylus abstrusus 5.4% (14/259), Cryptosporidium spp. 4.4% (9/204), Giardia species 3.9% (8/204), Taeniidae 1.2% (3/260) and Dipylidium caninum 0.4% (1/260). T. foetus was not identified. These results reveal a high level of parasitism in the shelters assessed, mainly by zoonotic agents from Toxocaridae and Ancylostomatidae families, and at a lower level by Taeniidae family and Cryptosporidium/Giardia species. Shelter overcrowding and the consequent close contact between animals, increases the likelihood of parasite transmission for parasites with direct life cycles, which may explain the results found for T. cati and Cystoisospora species. The lack of funding in animal shelters constitutes a real challenge in the implementation of regular prophylatic measures and disease management. The difficulties in managing these parasites, contributes to the infections, compromising animal health and welfare. It is expected that the increasing awareness on animal welfare in our society, may gather the means for achieving better conditions in animal shelters.
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Prior, Kimberley Faith. "The evolutionary ecology of circadian rhythms in malaria parasites." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/29562.

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Biological rhythms are thought to have evolved to enable organisms to organise their activities according to the Earth’s predictable cycles, but quantifying the fitness advantages of rhythms is challenging and data revealing their costs and benefits are scarce. More difficult still is explaining why parasites that exclusively live within the bodies of other organisms have biological rhythms. Rhythms exist in the development and traits of parasites, in host immune responses, and in disease susceptibility. This raises the possibility that timing matters for how hosts and parasites interact and, consequently, for the severity and transmission of diseases. Despite their obvious importance in other fields, circadian rhythms are a neglected aspect of ecology and evolutionary biology. The ambitions of this thesis are to integrate chronobiology, parasitology and evolutionary theory with mathematical models to obtain a greater understanding about how and suggest why malaria parasites have rhythms as well as the effect of infection on host rhythms. First, I identify how malaria parasites lose their developmental rhythms in culture, when they lack any potential time cues from the host. Next, I characterise parasite rhythms inside the mammalian host in terms of synchrony and timing and demonstrate there is genotype by environment interactions for characteristics of parasite rhythms. Then, I investigate the effect that parasite infection has on host rhythms and show there is variation between parasite genotypes in their effect on host locomotor activity and body temperature rhythms during infections. Finally, I explore which host rhythms may be driving parasite synchrony and timing and demonstrate the importance of peripheral host rhythms for the timing of malaria parasite developmental rhythms. The data presented here provides novel and important information on the role of rhythms during disease and opens up a new arena for studying host-parasite coevolution.

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Williams, Emily Rose-Margaret. "Parasites and the ecological undead: marine snails and their suite of trematodes." Thesis, The University of Sydney, 2012. https://hdl.handle.net/2123/28920.

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The invisible interactions between parasites and their hosts are important elements of the ecology and biology of host populations. Parasites can shape the morphology, distribution, physiology and behaviour of individual hosts - some commonly studied host-parasite interactions often involve gastropods and trematodes. Trematodes can have detrimental effects on their snail hosts, yet many such relationships are relatively unknown. One such relationship is that of the mud whelks, Velacumantus australis, many of which are infected by several species of parasitic trematode. Australian estuaries and lagoons are commonly populated with these snails. Little work has been done, however, on how these snails are affected by their trematodes. My overall aim was to create a more comprehensive picture of the relationship between trematodes and their snail hosts, since it is unknown what is occurring within populations of these snails in Australia. Through dissections and experiments, I described all the species infecting the snails, including those previously unknown to science; quantified infection prevalence within different populations of snails in New South Wales; compared infection with host size, both in situ and through growth of host bodies over time; assayed proteins and lipids from host tissues to quantify energy reserves; and finally, tested whether snails displayed different behaviours depending on infection status. My results show that parasitism varies temporally and on small and large spatial scales, most likely because of recruitment and presence of other hosts. The effects of parasitism on the host body include differences in growth and energy reserves, and appear to be influenced depending on the species of trematode. The activity and locomotory behaviour of snails is also affected by trematode infection, whether the snail has a neighbour, and the infection status of the neighbouring snail. These results show that the relationship between V australis and its trematodes is more complex than predicted and is influenced by dynamic interactions between spatial variability and parasitism. Future experiments with these snails and other snail-trematode relationships in similar systems should include different spatial scales as well as different species of trematodes in order to disentangle the relationships between parasitism and environmental variation.

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Rossanigo, Carlos Esteban. "Rôle de l'eau et de la température sur les taux de développement des nématodes parasites du tractus digestif des ruminants." Montpellier 2, 1992. http://www.theses.fr/1992MON20293.

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Les conditions climatiques ont un role preponderant sur la repartition geographique et temporelle des differentes especes de nematodes parasites des ruminants. Sur un exemple tire du parasitisme des bovins du centre-ouest d'argentine, temperature et pluviometrie contribuent a expliquer les niveaux d'infestation par les principaux genres. Un travail plus experimental est developpe en vue d'estimer le role de l'eau a proximite immediate des ufs et jeunes larves des nematodes (dans les feces), avec ou sans celui de la temperature, sur la partie du cycle de developpement allant de l'uf a la larve infestante. Par des depots de feces d'animaux parasites dans des situations climatiques diversifiees, il est montre que la temperature au sein des bouses etait le premier facteur conditionnant le taux de developpement des especes parasitant les bovins et que c'etait l'humidite ponderale des feces dans le cas des parasites d'ovin. Les exigences thermique et surtout hydriques sont definies au laboratoire pour huit especes parasites de bovins, ovins et cervides multipliees sur ovin. L'adaptation aux faibles humidites etait le principal caractere specifique. La taille des larves infestantes s'est averee dependre des conditions de developpement. Par des tests de laboratoire, il est montre que les petites larves developpees a des humidites faibles migraient et se degainaient plus lentement que les normales et semblaient avoir plus de mal a s'etablir chez l'hote. L'adaptation genetique aux conditions seches d'une lignee a ete tentee par une selection pendant 5 generations mais n'a pas revele d'evolution du taux de developpement dans ces conditions

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Chartier, Christophe. "Epidémiologie de l'infestation helminthique chez les bovins en Ituri (Haut-Zai͏̈re)." Montpellier 2, 1989. http://www.theses.fr/1989MON20253.

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La faune helminthique des bovins de l'ituri (haut-zaire), riche de trente especes parasites differentes, participe a la fois des zones tropicales d'afrique de l'est, des regions humides et des zones d'altitude. L'etude de la distribution geographique des helminthes fait apparaitre, pour les trematodes (fasciola gigantica, schistosoma bovis et dicrocoelium hospes), une importante disparite liee a la repartition des mollusques hotes intermediaires. Les nematodes ont, au contraire, une distribution plus homogene. La mesure du parasitisme helminthique des jeunes animaux, met en evidence la chronologie des infestations: toxocara vitulorum et strongyloides papillosus jusqu'a 4 mois, strongles digestifs de 4 a 12 mois, strongles digestifs et fasciola gigantica de 12 a 20 mois. Les variations saisonnieres de l'infestation helminthique sont mises en evidence, pour les strongles digestifs, dans les quatre zones ecologiques etudiees. L'intensite de ces fluctuations reste cependant moderee ce qui explique le faible retentissement de ce parasitisme sur les productions animales. Les variations saisonnieres de l'infestation par f. Gigantica n'apparaissent que dans les sites a saison seche prolongee

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Nkollo, Jean-Marie Faustin. "Les parasitoses intestinales au Cameroun." Bordeaux 2, 1992. http://www.theses.fr/1992BOR2P045.

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Duranton, Christelle. "Comparaison de l'infestation par Oestrus ovis (Linné, 1761) chez la chevre et le mouton." Toulouse 3, 1997. http://www.theses.fr/1997TOU30171.

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Strus ovis (linnaeus, 1761) est un parasite frequent chez le mouton et la chevre de nombreux pays mediterraneens et tropicaux, responsable d'une maladie (l'strose) due a la presence et au developpement de larves dans les cavites nasales de l'hote. Une etude bibliographique et une enquete epidemiologique menee a l'abattoir de pezenas ont montre que la prevalence et l'intensite de l'infestation sont plus importantes chez le mouton que chez la chevre naturellement infestes par strus ovis. Nous avons infeste experimentalement des chevreaux et des agneaux par des larves de premier stade d'strus ovis et compare le nombre de larves recoltees a l'abattage. Les resultats ont confirme que la chevre etait moins receptive a l'infestation par strus ovis. La nature des populations cellulaires recrutees, mastocytes et eosinophiles, au niveau de la muqueuse nasale du septum de chevreaux infestes experimentalement a permis de suspecter la participation d'un phenomene d'hypersensibilite dans la pathogenie de l'strose, confirmant des travaux precedents realises chez l'agneaux. Cependant, apres infestation unique, nous avons montre que le recrutement des eosinophiles et des mastocytes est beaucoup plus important chez les agneaux que chez les chevreaux ou les valeurs restent semblables a celles des temoins. Apres infestations repetitives ; le nombre d'eosinophiles trouves au niveau de la muqueuse nasale des chevreaux est 2,5 fois plus faible que celui obtenu pour les agneaux ; les mastocytes de chevreaux sont tres peu recrutes. Le phenomene d'hypersensibilite developpe par les chevreaux n'est donc pas aussi important que celui des agneaux. La reactivite de certains facteurs de l'immunite peut etre impliquee dans cette difference de reponse cellulaire. Nous avons comparee in vitro, l'emission de monoxyde d'azote par les macrophages de chevreaux et d'agneaux pour determiner si l'infestation par strus ovis en modifiant la production. La toxicite de ce radical oxydatif vis a vis des larves de premiers stades a ete testee et prouvee in vitro. Pour les deux especes hotes, la stimulation in vitro des macrophages par l'extrait antigenique l1 diminue la production de monoxyde d'azote tandis que l'extrait antigenique l2 l'augmente significativement. Compte-tenu des donnees epidemiologiques, nous avons etudie par les marqueurs genomiques (rapd), la diversite genetique des populations d'strus ovis de moutons et de chevres. Ce travail constitue une premiere analyse genetique realisee chez cette espece. Nos resultats ont montre d'une part, une forte diversite intra-population et d'autre part, une importante divergence genetique entre les populations d'stres de moutons et de chevres.

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Borghesan, Tarcilla Corrente. "Diversidade e filogenia de tripanossomatídeos parasitas de dípteros." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/42/42135/tde-03062014-105719/.

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A família Trypanosomatidae compreende parasitas obrigatórios de vertebrados, plantas e invertebrados, as espécies exclusivas de insetos infectam principalmente dípteras e hemípteras. Nós revisamos a taxonomia de Herpetomonas e tripanossomatídeos de insetos que abrigam simbionte (SHT), comparando tripanossomatídeos da América do Sul e África. As filogenias revelaram duas novas espécies e possibilitou revalidar os gêneros Strigomonas e Angomonas. As análises filogenéticas revelaram três novas espécies de endossimbiontes proteobacteriano e apoiam a história evolutiva convergente entre hospedeiros e simbiontes. O DNA barcoding de 364 culturas de moscas identificaram 70 culturas (20%) como Angomonas, 71% deles de Calliphoridae. O gênero Herpetomonas compreende agora 13 espécies válidas, incluindo cinco novas espécies. Algumas espécies de Herpetomonas são parasitas generalistas de moscas e parecem ser tão cosmopolita como seus hospedeiros. Os taxon propostos podem ajudar a elaborar critérios mais eficientes para uma classificação melhor dos tripanossomatídeos.
Trypanosomatidae comprises obligate parasites of vertebrates, plants and invertebrates, the species exclusive of insects infect mostly dipterans and hemipterans. We revise the taxonomy of Herpetomonas and Symbiont Harboring Trypanosomatids (SHTs), by comparing trypanosomatids from South America and Africa. The phylogenies disclosed two new species and revalidated the genera Strigomonas and Angomonas. Phylogenetic analyses revealed 3 new species of proteobacterial endosymbionts and support a co-divergent host-symbiont evolutionary history. DNA barcoding of 364 cultures from flies identified 70 cultures (20%) as Angomonas, 71% of them from Calliphoridae. The recent dispersion of calliphorids was important in the dispersal of Angomonas worldwide. The genus Herpetomonas now comprises 13 valid species including 5 new species. Some species of Herpetomonas are generalist parasites of flies and appear to be as cosmopolitan as their hosts. The proposed taxa may help to elaborate more efficient criteria for a better classification of the Trypanosomatidae.

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23

Inácio, Sandra Valéria. "Validação diagnóstica para a detecção de Cryptosporidium spp. em bovinos /." Araçatuba, 2016. http://hdl.handle.net/11449/133993.

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Orientador: Katia Denise Saraiva Bresciani
Banca: Simone Baldini Lucheis
Banca: Valéria Maria Savoya da Silva
Banca: Mônica Regina Vendrame Amarante
Banca: Silvia Helena venturoli Perri
Resumo: A criptosporidiose, tanto humana como animal, tem distribuição cosmopolita. Esse parasito ocasiona diarreia em bezerros, retardo no crescimento, mortalidade e consequentes perdas econômicas. Nós realizamos a viabilização, desenvolvimento, avaliação e validação intralaboratorial de uma nova técnica parasitológica para a análise em microscopia óptica de oocistos de Cryptosporidium spp., denominada de TF-Test Coccidia, em amostras fecais de bezerros do município de Araçatuba, São Paulo. Para o desenvolvimento deste estudo e confirmação da nova técnica diagnóstica TF-Test Coccidia foram empregadas duas metodologias: centrífugo-sedimentação seguida da coloração negativa de verde malaquita (CSN-Malaquita) e Nested-PCR. Amostras positivas e negativas de bezerros foram utilizadas para a confecção e validação do TF-Test Coccidia. Portanto, podemos concluir a eficácia da técnica parasitológica de TF-Test Coccidia, na detecção de oocistos do parasito Cryptosporidium spp. e observamos boa concentração e morfologia das estruturas de eliminação do mencionado parasito, com baixa quantidade de impureza em esfregaço fecal.
Abstract: Cryptosporidiosis, both human and animal, has a worldwide distribution. This parasite causes diarrhea in calves, growth retardation, mortality and consequent economic losses. We performed the feasibility, development, evaluation and within-laboratory validation of a new parasitological technique by optical microscopy analysis of Cryptosporidium spp., Called TF-Test Coccidia in fecal samples of calves in the city of Araçatuba, São Paulo. To develop this study and confirmation of the new diagnostic technique TF-Test Coccidia were employed two methodologies: the centrifugal sedimentation followed by negative staining of malachite green (CSN-Malachite) and nested PCR. Positive and negative samples from calves were used for the preparation and validation of TF-Test Coccidia. Therefore, we conclude the effectiveness of parasitological technique TF-Test Coccidia, on the oocysts detection of the parasite Cryptosporidium spp. and observe good concentration and morphology of eliminated parasitic structures mentioned, with low amount of impurity in fecal smear.
Doutor

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24

PEREIRA, Aldenice Nazar? Silva. "A comunidade parasit?ria da Trilha, Mullus argentinae Hubbs & Marini, 1933 (Perciformes, Mullidae): aspectos taxon?micos e seu uso para a discrimina??o de estoques populacionais." Universidade Federal Rural do Rio de Janeiro, 2012. https://tede.ufrrj.br/jspui/handle/jspui/1691.

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CNPq
Previous studies of the parasitic fauna of the goatfish (Mullus argentinae) from Brazil and Argentina show a significant diversity of species and suggest that this host feature is a good model to test hypotheses for the distribution of parasites and their use as biological indicators of the presence of stocks or different populations of hosts and allowing information relevant to good management of this species. The purpose of this work was to study the composition and structure of parasites communities of the goatfish (M. argentinae), assess whether the temporal variation influences the parasitic fauna and verify its use as a tool for discrimination of possible stocks of this species throughout its geographical distribution, which includes the coast of Brazil and Argentina. During the period of March 2010 to July 2011, were collected 430 specimens of M. argentinae of three locations along the Brazilian coast and an area of the coast of Argentina. In statistics, the quantitative approach was made at the level of parasitic infrapopulations and ecological descriptors were calculated for each parasite species in each area. Species with prevalence >10% in at least one of the localities were analyzed in the ? ? (Chi-square) to test significant differences in prevalence between locations. ANOVA and a Tukey test a posteriori were performed to test for unequal samples. It was analyzed similarity indices of Jaccard and qualitative Bray-Curtis and quantitative and multivariate analysis. Discriminate analysis was used to detect differences between locations and identify species of parasites responsible for these differences.
Estudos pr?vios da fauna parasit?ria da Trilha (Mullus argentinae) em amostras provenientes do Brasil e da Argentina mostram uma significativa diversidade de esp?cies e sugerem que este recurso ictiol?gico ? um bom modelo para testar hip?teses de distribui??o de parasitos e seu uso como indicadores biol?gicos da presen?a de estoques ou de popula??es diferentes de hospedeiros e que permitam obter informa??es relevantes para um adequado manejo desta esp?cie. O prop?sito deste trabalho foi estudar a composi??o e estrutura das comunidades parasit?rias da Trilha (M. argentinae), avaliar se a varia??o temporal da amostragem influencia na fauna parasit?ria e verificar seu uso como ferramenta para a discrimina??o de poss?veis estoques desta esp?cie ao longo da sua distribui??o geogr?fica, que inclui o litoral do Brasil e da Argentina. Durante o per?odo de mar?o de 2010 a julho de 2011, foram coletados um total de 430 esp?cimes de M. argentinae de tr?s localidades do litoral brasileiro (Rio de Janeiro, Santa Catarina e Rio Grande do Sul) e de uma localidade do litoral da Argentina (Mar Del Plata). A abordagem quantitativa foi feita em n?vel de infrapopula??es parasit?rias, sendo calculados os descritores quantitativos, para cada esp?cie de parasito de cada ?rea estudada. Para as esp?cies com preval?ncia >10% foram feitas an?lises de ?? (qui-quadrado) para testar diferen?as significantivas de preval?ncia entre localidades. ANOVA e um teste Tukey a posteriori foram feitos para testar se existe diferen?a entre grupos. Foram utilizados tamb?m os ?ndices de similaridade qualitativa de Jaccard e quantitativa de Bray-Curtis. Na an?lise multivariada, primeiramente desenvolveu-se uma an?lise de agrupamentos, que agrupa os parasitos pela abund?ncia de esp?cies existentes nas localidades. A An?lise discriminante foi usada para detectar diferen?as entre localidades e entre diferentes ?pocas de coleta e identificar esp?cies de parasitos respons?veis por estas diferen?as.

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25

Campbell, Scott Edward. "Secreted proteins in Microsporidian parasites : a functional and evolutionary perspective on host-parasite interactions." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14523.

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The Microsporidia form a phylum of obligate intracellular parasites known to cause disease in humans and a diverse range of economically important animal species. Once classified as ‘primitive’ eukaryotes, it is now recognised that the peculiarities of microsporidian genomics and cell biology are, in fact, the consequence of extreme reduction allowed by an intimate relationship with the host cell. Excluding survival as an extracellular spore, microsporidia are in direct contact with the host throughout their developmental lifecycle, from entry to egress. Host cell manipulations have been described in morphological terms, but despite this, characterisation of such processes at the molecular level remains challenging. The logistics of the microsporidian lifecycle suggest secreted proteins and membrane proteins with extracellular domains may be involved in virulence and implicated in host cell manipulation. This study employs bioinformatic tools to predict secreted proteins in diverse microsporidia and comparative genomics to identify conserved proteins which may be required for host cell manipulation, pathogenicity and lifecycle progression. The protein complement secreted into the extracellular environment during microsporidian spore germination, a lifecycle stage required for host cell invasion, is identified experimentally. This analysis suggests that novel microsporidian specific hypothetical proteins, that is, proteins with no functional annotation or domain, play a significant role during parasite invasion of the host and provides the first identification of potential microsporidian effector proteins. Aiming to address microsporidian pathogenicity during intracellular stages, candidate virulence factor proteins, namely a hemolysin and a protein tyrosine phosphatase are also characterised and localised in situ. Lastly, an animal-derived horizontal gene transfer event is used in conjunction with both the fossil record and molecular dating approaches to add timescale to the microsporidian diversification. This work suggests that microsporidia radiated recently, achieving extreme cellular diversity, acquiring a novel infection mechanism and undergoing vast speciation in a short evolutionary timescale, likely within the last 200 million years.

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26

O'Brien, Chris. "Appreciating the Importance of Parasites: Analyzing and Understanding the Ecology of Parasite-Host Interactions." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194212.

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There is a growing interest in the nature of parasite-host interactions, the role these relationships play in ecological communities, and how human activities alter these associations. Furthermore, because inference about these interactions is usually gained by methods of statistical hypothesis testing, additional importance should be placed on the analysis and interpretation of parasite-host interactions. In this dissertation I address these ideas in three separate but interrelated studies with the three following questions: 1) How do two parasites with complex life-cycles alter the behavior of a novel amphipod host, and how do host and non-host predators respond to infected amphipod prey? In contrast to other studies, I found that two parasites of an endemic amphipod at Montezuma Well had little affect on their amphipod host, and that these associations had little affect on predation rates by both host and non-host predators. Results from this study underscore the importance of further investigating novel parasite-host interactions and placing them in their phylogenetic and evolutionary context. 2) Does human recreation affect spatial patterns of infection in an otherwise natural ecosystem? This study demonstrates that human visitors to Montezuma Castle National Monument alter patterns of waterfowl space use that in turn affect spatial patterns of disease in invertebrate hosts. This is the first study to document such an effect, and I discuss the important implications of this finding. 3) How is hypothesis testing applied in studies of wildlife disease, what conclusions can we make about the relative usefulness of these methodologies, and how can the analysis and interpretation of wildlife disease studies be improved? In this final study I conducted a literature review, computed statistical power for methodologies used in the literature, and re-analyzed published data to provide an example of the advantages of my suggested approach. I conclude that many studies report findings using methods that could be more informative and some studies may lack statistical power, demonstrating the importance of using prospective power analysis in the design of future studies. Furthermore, using statistical techniques that estimate the observed effect size can aid in increasing information transfer in studies of wildlife disease.

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Brown, S. "Social evolution in parasites." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597008.

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The ability of parasites to manipulate their hosts is the major empirical theme of this thesis, in particular the problem of cooperation among parasites that host manipulation entails. Contributing to host manipulation is likely to bear a cost to the individual, while the benefits will be felt by every conspecific parasite (and others) within the host. I develop in Chapter Two a game-theoretical model of parasite-induced host manipulation, which focuses on co-operative interactions between individuals and a larger group. In Chapters Three and Four I consider two macroparasitic case-studies. Chapter Five marks the beginning of the macroparasitic half of the thesis, with a study of the cestode Ligula intestinalis in its intermediate host, the Roach (Rutilus rutilus). Chapter six uses a similar mix of statistical and analytic approaches to investigate the interaction between the manipulative trematode Microphallus papillorobustus and its intermediate gammarid host, with a focus on the potential costs of host manipulation. Chapters Five and Six introduce aggregation as respectively a side-effect and a cost of manipulation. In Chapter Seven, I add that, should aggregation be costly to established worms, the probability of subsequent recruits may itself fall under the influence of established parasites. Using the case study of schistosome worms in their definitive mammalian hosts, I develop a stochastic-simulation model to explore the potential for adaptive population regulation in parasites. In Chapter Eight, I review the progress made in this thesis, with an emphasis on developing a synthesis between models of virulence and of host manipulation.

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Dale, Denver Dudley Stanton. "Parasites and host nutrition." Thesis, University of Oxford, 1993. http://ora.ox.ac.uk/objects/uuid:5bc8aebc-fcfa-4301-8d04-4ebc89fb1c8a.

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Vankeuren, Jody L. "Parasites Predators and Symbionts." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1619475426952694.

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30

Steinfelder, Svenja. "Immune modulation by parasites." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2007. http://dx.doi.org/10.18452/15682.

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Die Infektion mit Schistosoma mansoni resultiert in einer Th2-Immunantwort mit Eosinophilie und erhöhtem IgE-Titer, wobei der wasserlösliche Extrakt der S. mansoni Eier (SEA) ausreicht um diese Reaktion auszulösen. In der vorliegenden Arbeit konnte demonstriert werden, dass sich IL-4-produzierende CD4+ T-Lymphozyten in Zellkulturen mit SEA-konditionierten Dendritischen Zellen (DCs) trotz gleichzeitig vorkommenden IFN-gamma entwickeln und SEA die Expression von Faktoren in DCs, die üblicherweise mit einer Th1-Antwort einhergehen, auf Transkriptions- und Proteinebene selektiv hemmt. Um den Faktor aus S. mansoni Eiern zu isolieren, der zur Expression von IL-4 in CD4+ Zellen und zur Inhibition von IL-12 in DCs führt, wurde eine Gelfiltrationschromatographie der exkretorisch/sekretorischen Ei-antigene (ES) durchgeführt und die Fraktionen in vitro getestet. Darin wurde gezeigt, dass Fraktionen mit einer Proteinbande von 30 kD die Expression von IL-4 in CD4+ Zellen induzieren. Dieses ES-Protein wurde durch N-terminale Sequenzierung als hepatotoxische Ribonuclease Omega-1 identifiziert, welches ebenfalls die Expression von IL-12 in DCs inhibiert und die Produktion von IL-4 in CD4+ Zellen bei einer 10-fach geringeren Proteinkonzentration als mit dem Kontrollansatz SEA induziert. Zudem sollte untersucht werden, inwieweit Toll-like Rezeptoren in der Generierung einer Th2 Antwort gegen schistosomale Antigene involviert sind. Dazu wurden TLR2-, TLR3-, TLR4- und MyD88-defiziente Mäuse mit S. mansoni infiziert und immunologische und pathologische Daten in der akuten und chronischen Phase der Infektion analysiert. Demnach sind TLR2, TLR3, TLR4 und MyD88-abhängige Signaltransduktionswege nicht für eine-Th2 Antwort notwendig, jedoch ist letzteres Molekül in der Ausprägung der typischen Leberfibrose involviert.
Infection with Schistosoma mansoni results in the induction of a Th2 immune response, eosinophilia and increased levels of IgE. The water-soluble extract of S. mansoni eggs (SEA) is sufficient to promote TH2 polarization in a dendritic cell-dependent manner. In this thesis, it was demonstrated that IL-4+ CD4+ cells emerge in cultures with SEA-conditioned dendritic cells (DCs) in the presence of IFN-gamma and that SEA inhibits selectively the expression of IL-12 and co-stimulatory markers in DCs on the transcriptional and protein level. To identify the putative protein in S. mansoni eggs mediating a Th2 induction, a gel filtration chromatography of the excretory/secretory egg antigens (ES) was conducted and the fractions tested in vitro. Fractions containing a single band of 30 kD were sufficient to promote IL-4 induction in naïve CD4+ cells. Using N-terminal sequencing this ES-protein was identified as the hepatotoxic S. mansoni ribonuclease omega-1 which displayed both biological functions observed with SEA: inhibition of IL-12 in LPS-stimulated DCs and induction of IL-4+ CD4 cells at a 10 fold lower protein concentration than SEA. In order to understand, if the innate immune receptors TLR2, TLR3, TLR4 or the TLR adaptor molecule MyD88 are involved in the generation of the Th2 response against schistosomal antigens, the respective knock out mice were infected and immunological and pathological parameters were analyzed during acute and chronic phase of infection. This study showed that during S. mansoni infection TLR2, TLR3, TLR4 and TLR activation through the MyD88-dependent pathway are neither required for the induction (priming and polarization) nor for the down-regulation of Th2 responses, however, the fibrotic response against S. mansoni eggs was significantly reduced in MyD88-deficient mice suggesting a detrimental role of this pathway in liver pathology.

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Buttar, Birpal Singh. "Effect of thermal and ensilation treatments on viability of Taenia hydatigena eggs." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Dissertations/Spring2010/B_Buttar_1041310.pdf.

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32

Leducq, Régine. "Echinococcose alvéolaire : migration et différenciation dans l'hôte intermédiaire expérimental. Aspects morphologiques et biochimiques." Montpellier 2, 1992. http://www.theses.fr/1992MON20181.

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Dans le cadre des interactions heterospecifiques durables, une etude des relations hote-parasite est realisee a partir du modele metacestode e. Multilocularis/hote intermediaire experimental (la gerbille de chine meriones unguiculatus). Dans un premier temps, les parametres influencant la dissemination de l'echinocoque (en tant que population clonale) sont etudies au travers de differents protocoles d'infestations secondaires. Les differents types de formes larvaires a l'origine des migrations dans l'hote sont decrits ainsi que les voies de migration preferentiellement empruntees. Une attention particuliere est portee a l'atteinte du systeme lymphatique. Les caracteristiques des infestations secondaires sous-cutanees et intra-peritoneales, sont discutees et comparees a celles de l'echinococcose primaire. Dans un deuxieme temps, les modes de differenciation du metacestode en tant qu'individu sont analyses grace a des etudes morphologiques et biochimiques. Les phases de l'ontogenese du parasite sont etablies en fonction des transformations tegumentaires. Les marquages des glycoconjugues a l'aide de lectines confirment la mise en evidence d'une regionalisation tegumentaire et d'une evolution des relations hote-parasite favorisant le developpement du metacestode. Une etude preliminaire des glycoproteines parasitaires est realisee a l'aide des techniques de sds-page et western blotting. Ces resultats suggerent que l'ontogenese du parasite serait determinee par des facteurs intrinseques et extrinseques (milieux physico-chimiques et immunologiques) evoluant dans le temps et l'espace

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Pereira, Felipe Bisaggio. "Estrutura da comunidade de helmintos associados ao lagarto Tropidurus torquatus (Squamata: Tropiduridae) em uma área de afloramento rochoso no distrito de Toledos, Juiz de Fora, MG." Universidade Federal de Juiz de Fora (UFJF), 2010. https://repositorio.ufjf.br/jspui/handle/ufjf/3017.

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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
A comunidade parasitária do lagarto Tropidurus torquatus em uma área de campo rupestre localizada no estado de Minas Gerais, sudeste do Brasil, foi estudada. Dos 110 hospedeiros analisados, 92 (83,6%) estavam infectados. Foram encontradas cinco espécies de helmintos, três de nematóide: Physaloptera lutzi, Parapharyngodon sp. e Oswaldofilaria sp., uma espécie de cestóide e um cistacanto não identificados. Apenas as espécies de nematóides apresentaram dados suficientes para analises ecológicas, sendo P. lutzi a espécie mais prevalente (67,3%) e com maior intensidade parasitária (4,86±4,85). Somente para Oswaldofilaria sp. foram encontradas diferenças significativas na prevalência e intensidade parasitária entre hospedeiros fêmeas e machos, esses últimos apresentando os maiores valores. A intensidade parasitária total e de P. lutzi também diferiram entre os sexos de hospedeiros com machos apresentando os maiores valores. O tamanho corporal do hospedeiro correlacionou-se de forma positiva com a intensidade de infecção de todas as espécies de nematóides. A sazonalidade local não influenciou de forma significativa a estrutura da comunidade componente de parasitos estudada. Aspectos do hospedeiro como dieta, dimorfismo sexual e comportamento (territorialiasmo e forrageamento) representaram importantes fatores na determinação da estrutura dessa comunidade de helmintos. De maneira geral, a comunidade parasitária apresentou baixa riqueza de espécies e um caráter não interativo, características comuns em comunidades parasitárias de répteis como hospedeiros.
The helminth community of the lizard Tropidurus torquatus from a rocky outcrop located in Minas Gerais state, southeast Brazil, was studied. Ninety two of the one hundred ten individuals examined (83,6%) harbored helminths. A total of five helminth species were found, tree nematodes: Physaloptera lutzi, Parapharyngodon sp. and Oswaldofilaria sp., one cestode species and one acanthocaphalan cystacanth not identified. Only nematode species had sufficient data to perform ecological analysis with Physaloptera lutzi showing the highest prevalence (67,3%) and mean intensity (4,86±4,85). Prevalence and intensity of infection between males and females hosts differed only for Oswaldofilaria sp., with males showing the highest values. Total and P. lutzi intensity of infection were different among males and females hosts, with males showing the highest values. The host body size was positively related to intensity of infection for all nematode species. Local seasonality had no influence in the helminth community structure. Host diet, sexual dimorphism and behavior (territorialism, forage strategy) represented important factors in the structuring of this parasite community. In general lines, the helminth community was species poor and non interactive, representing a typical community structure found in herps hosts.

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Mottuel, de Brauer Christabel. "Les parasites dans les boues résiduaires des stations d'épuration." Paris 5, 1992. http://www.theses.fr/1992PA05P153.

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35

Fredensborg, Brian Lund, and n/a. "Ecological interactions between the trematode parasite Maritrema novaezealandensis (Microphallidae) and its intermediate hosts in the New Zealand intertidal soft-sediment community." University of Otago. Department of Zoology, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060810.154001.

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Most, if not all, animals will at some stage in their lives encounter parasites. Some of the most widespread and abundant parasites belong to the Class Trematoda. Trematodes often have a substantial negative impact on individual intermediate host ecology. In this thesis, I investigate ecological and evolutionary consequences of the interaction between the microphallid trematode, Maritrema novaezealandensis, and its intermediate snail and crustacean hosts. Parasites often show a heterogeneous spatial distribution pattern in natural animal host populations. In this study, factors determining the spatial distribution of larval trematodes in Zeacumantus subcarinatus were investigated at two spatial scales (within and among bays). The distribution of shorebird definitive hosts explained a significant amount of the variation in the distribution of trematodes among bays. However, within a bay, other factors override the effect of bird distribution. The influence of larval trematodes on reproduction, survival and population density of Z. subcarinatus was investigated using laboratory and field studies. In the laboratory, it was found that larval trematodes induce castration and mortality of Z. subcarinatus. The field study revealed that the local prevalence of trematodes had a significant negative effect on population density of Z. subcarinatus. Through castration, trematodes act as strong selective agents on snail host life history. The effect of trematodes on life history characteristics (reproductive effort, juvenile growth, size at maturity and susceptibility to trematode infections) were investigated among natural populations of Z subcarinatus. Reproductive effort was not higher for uninfected females from populations where the risk of becoming infected was high. However, offspring from those populations were significantly larger, and laboratory-reared juveniles grew significantly faster than conspecifics from other populations. In addition, size at maturity was negatively correlated with trematode prevalence across snail populations. Z. subcarinatus thus adapts to a high local risk of trematode infection by reaching maturity early, thereby increasing the chance of reproducing. The influence of M. novaezealandensis on the survial of the amphipod host, Paracalliope novizealandiae was examined using experimental infections and field observations. The experimental infections demonstrated that parasite-induced mortality was intensity-dependent. The number of M. novaezealandensis per amphipod was too low to significantly induce host mortality in the field. However, the transmission strategy of this parasite allows it to affect host populations during weather conditions ideal for trematode transmission. Trematode strategies in the second intermediate host are important to the understanding of host-parasite co-evolution and the evolution of parasite life cycles. In this study, potential density-dependent effects at the metacercarial stage on size and fecundity of in vitro adult M. novaezealandensis was examined in both experimentally infected P. novizealandiae and naturally infected Macrophthalmus hirtipes. For this purpose, a method to excyst and cultivate M. novaezealandensis metacercariae to an egg producing stage, was developed. Naturally infected M. hirtipes also harboured larval stages of three other helminths. Crowding effects in the two crustacean hosts were expressed as a decreased volume and smaller egg production of in vitro adult M. novaezealandensis. In addition, interspecific interactions among parasite species were observed in crab hosts. The work in this thesis provides evidence that M. novaezealandensis significantly and negatively affect intermediate host ecology. The heterogeneous distribution of trematodes causes differential effects among host populations with subsequent effects on the life history of snail hosts. In addition, this study demonstrates that parasites interact within their second intermediate host with possible implications for the way parasites exploit their hosts.

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Dubois, Jacques. "Phylogénie moléculaire et morphologique des Pimplinae (Hymenoptera, Ichneumonidae) parasites d'araignées : scénarios évolutifs du mode de parasitisme." Paris, Muséum national d'histoire naturelle, 2005. http://www.theses.fr/2005MNHN0063.

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Les Pimplinae sont une des sous-familles d’Ichneumonidae dont les modalités de relation hôtes-parasitoïdes sont les plus diversifiées et dont la biologie est parmi les mieux connues. Des hypothèses phylogénétiques ayant déjà été établies sur des bases morphologiques pour la sous-famille, nous avons (1) confirmé ces hypothèses à l’échelle générique à partir de données moléculaires originales basées sur l‘étude des ADNr 28S,16S et du CO1; (2) approfondi les relations de parenté au sein du groupe de genres Polysphincta ; (3) établi des hypothèses sur l’évolution du parasitisme au sein du groupe. Une phylogénie morphologique robuste du groupe de genres Polysphincta (parasitoïdes d’araignées) a permis de délimiter 21 genres dont trois nouveaux. L’inclusion dans la matrice de caractères biologiques a permis de retracer l’histoire évolutive du groupe à travers l’évolution du mode de parasitisme et d’autres traits comportementaux liés à la larve et à son cocon
Pimplinae are the subfamily whose parasitism patterns are the most diversified and biology one of the best known within the Ichneumonidae. Hypotheses on Pimplinae phylogeny being already established from morphological data, this work aimed at (1) supplying original molecular data, based on 28S and 16S rDNAs and CO1 analyses, in order to test the morphological hypotheses at a generic level; (2) detailing relationships within the Polysphincta genus group ; (3) establishing hypotheses about the evolution of parasitism patterns within this group. The study of the Polysphincta genus group, based on a morphological phylogeny, led to the redefinition of 21 genera, among which 3 were new. The subsequent inclusion of biological characters in the matrix enabled to retrace the evolutionary history of this group through the evolution of parasitism patterns and other behavioural traits of the larva and its cocoon

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Tabouret, Guillaume. "Oestrus ovis(linné 1761) [Diptera : oestridae] chez les ovins : application à la caractérisation des tumeurs mammaires." Toulouse 3, 2001. http://www.theses.fr/2001TOU30021.

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Nno, Mabiala Alix Dania. "Mécanismes et agents de la virulence chez les parasitoïdes hyménoptères Braconides du genre Asobara : le cas particulier d'A. Japonica." Amiens, 2009. http://www.theses.fr/2009AMIE0109.

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Le succès reproducteur d'un parasitoïde dépend en grande partie de sa capacité à infester son hôte et à s’y développer. Les parasites sont généralement capables d’éviter, de neutraliser ou de détourner la réponse immunitaire innée de leur hôte. Le processus le plus répandu est la production de facteurs immunosuppresseurs bloquant cette réponse, ou de facteurs toxiques provoquant la mort des cellules de défense. Ce travail de thèse porte sur la comparaison des mécanismes et des agents de la virulence chez les Hyménoptères braconides du genre Asobara. L’étude a porté sur deux espèces, A. Japonica et A. Persimilis, parasitoïdes de larves de D. Melanogaster. Les résultats ont été comparés à ceux précédemment décrits chez A. Tabida et A. Citri. Nous avons montré que la stratégie d’immunosuppression développée par l’espèce A. Japonica lui permet d’échapper dans 100 % des cas à l’encapsulement par les larves de D. Melanogaster. La stratégie de virulence de ce parasitoïde est basée sur une altération complète de l’organe hématopoïétique, ce qui se traduit par une incapacité de la larve hôte à amplifier sa population hémocytaire, toutes catégories hémocytaires confondues. En revanche, les œufs d’A. Persimilis se font encapsuler dans 13% des cas par les larves de D. Melanogaster. Ce parasitoïde affecte également l’organe hématopoïétique mais de façon plus limitée. Chez les larves hôtes, la prolifération des seuls lamellocytes semble être affectée suite à l’infestation par A. Persimilis. La recherche des facteurs responsables de la virulence a conduit à la démonstration d’un effet paralysant puis mortel des venins d’A. Japonica et d’A. Persimilis. De façon remarquable, cet effet peut-être régulé par l’injection d’extraits ovariens de ces parasitoïdes. Les sécrétions venimeuses et ovariennes des femelles d’A. Japonica et d’A. Persimilis seraient donc indispensables au succès du développement parasitaire. L’identification des composés venimeux a été initiée chez A. Japonica, espèce chez laquelle les effets toxiques et immunosuppresseurs sont les plus marqués. On s’est aussi interrogé sur la convergence, ou non, des stratégies et agents développés par les Hyménoptères parasitoïdes pour immuno-déprimer leur hôte. On constate qu’au sein de la communauté des parasitoïdes larvaires de drosophiles, il existe une hétérogénéité des mécanismes et agents immunosuppresseurs, et que cette hétérogénéité dépasse le cadre du genre Asobara
Success of parasitoids depends on their ability to infest a host and to complete their development. Endophagous parasites are able to avoid, neutralize or deflect the innate immune response of encapsulation by the hemocytes of their host. The most common mechanism is the production of either immunosuppressive factors blocking this response or of toxic factors causing the death of the hemocytic cells. In this thesis, we compared the mechanisms and agents of the virulence in Hymenoptera braconid species of the genus Asobara. The two species A. Japonica and A. Persimilis, parasitoids of Drosophila larvae, were studied. Results were compared to those previously obtained in A. Tabida and A. Citri. We here show that A. Japonica strategy of immunosuppression permits the parasitoid to successfully escape encapsulation in 100% of the D. Melanogaster parasitized hosts. The virulence strategy of this species is based on the overall destruction of the host’s hematopoietic organ, associated with the inability of the larval host to amplify any hemocyte type. Differently, A. Persimilis eggs are encapsulated in 13% of D. Melanogaster host larvae. This parasitoid species affects, too, the host hematopoietic organ, although this effect is limited compared to A. Japonica. Lamellocytes, which number does not increase post-parasitization, seem to be the only host’s hemocyte type which is affected by A. Persimilis. The analysis of the factors responsible of the parasitoids virulence permitted to demonstrate a paralyzing then deadly effect of the venoms from both A. Japonica and A. Persimilis. Surprisingly, the deadly effect is regulated by the female wasps’ ovarian fluids. Therefore, both venom and ovarian fluids of the female wasps appear to be required for the successful development of the parasitoids. The identification of the wasps’ venom components has been initiated in A. Japonica, the species presenting the most toxic and immunosuppressive effect. We ask the question of the possible convergence between the strategies and agents developed by hymenopteran parasitoids to immunodepress their hosts. It appears that within the community of Drosophila larval parasitoids, there is some heterogeneity of the mechanisms and agents of immunosuppression, and that this heterogeneity is beyond the scope of the Asobara genus

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Badets, Mathieu. "Etude de la plasticité de développement de Polystoma gallieni, parasite de la rainette méridionale Hyla meridionalis : approches écologiques et moléculaires." Perpignan, 2008. http://www.theses.fr/2008PERP0937.

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La théorie synthétique de l'évolution attribue aux processus du développement une nouvelle dimension dans notre compréhension de l'histoire de la vie. Comme les forces de sélection naturelles et sexuelles, les forces du développement pourraient favoriser ou contraindre la diversification des espèces. Par le jeu d'une combinatoire génétique et par une étonnante capacité d'interaction avec l'environnement, le développement d'un individu pourrait donc être dévié dans sa trajectoire afin d'augmenter survie et reproduction. Ainsi, le développement qui permet l'expression d'une information (génétique) dans un système (écologique), serait le siège de compromis stratégiques touchant le cœur même du mot adaptation. Dans le cas des espèces ayant un mode de vie parasite, la stratégie de développement recouvre souvent celle de la transmission. D'un hôte à un autre au sein d'un écosystème, l'espèce parasite doit passer outre de nombreux filtres qui limitent sa capacité à se transmettre et à se reproduire. Que dire alors de cette surprenante plasticité dont fait preuve un parasite du genre Polystoma pour achever son cycle ? En fonction des caractéristiques de son hôte, le parasite alterne ses modes de développement pour profiter au mieux des opportunités qui lui sont offertes. Ce travail tente de décrire comment cette dualité stratégique parasite traduit l'importance des contraintes historiques et écologiques pour identifier les sources de pressions sélectives. Un questionnement intégratif du développement permet alors de rendre compte de la transmission au sein d'un écosystème temporaire et hétérogène
Within the synthetic theory of evolution, the processes and patterns of development highlight a new dimension into our understanding of the history of life. Like the natural and sexual forces of selection, development could promote or constrain the diversification of species. Through a combination of genetic modules and an amazing ability to interact with the environment, the development of an individual could be deflected in its trajectory to increase survival and reproduction. Therefore development which allows the expression of information (genetic) in a (ecological) system, would involve strategic trade-off revealing fine tuned adaptations. When species present a parasitic lifestyle, developmental strategy often includes this of transmission. Going from host to host within an ecosystem, the parasite has to bypass many filters that limit its ability to transmit and reproduce. What about the surprising plasticity triggered by a parasite of the genus Polystoma to complete its cycle? Depending on the characteristics of its host, the parasite alternates its developmental pathways in regards of transmission opportunities. This work shade lights on the importance of historical and ecological constraints behind developmental mechanisms and tempts to identify the source of selective pressures. Sole an integrative approach of the parasite development can report how the transmission may occur within a temporary and heterogeneous ecosystem

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40

Segonds-Pichon, Anne. "L'interaction hôte-parasite chez le chevreuil (Capreolus capreolus) : étude éco-épidémiologique de la relation entre les nématodes gastro-intestinaux et pulmonaires et la condition corporelle de l'hôte dans des populations contrastées." Lyon 1, 2001. http://www.theses.fr/2001LYO10091.

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L'objectif de notre étude a été d'apporter des connaissances nouvelles sur la dynamique de la relation hôte-parasite dans le cas particulier du chevreuil et des nématodes qu'il héberge. Elle s'est déroulée sur 5 années et a permis la collecte et l'analyse coprologique puis statistique de 1607 prélèvements provenant de 7 populations de chevreuils contrastées sur le plan du milieu et de la densité relative aux ressources. L'helminthofaune observée correspond aux espèces de nématodes digestifs et pulmonaires généralement retrouvées en France. Après avoir établi la validité de la méthode coprologique dans le cadre d'une comparaison inter-populationnelle, nous avons mis en évidence la relation négative unissant la masse corporelle des chevreuils à leurs charges parasitaires digestives et pulmonaires. Nous avons également pu observer que la distribution des oeufs et des larves dans les matières fécales était agrégative. L'agrégation parasitaire est plus forte ou tend à l'etre chez les adultes, en particulier chez les femelles et lorsque l'abondance de la population d'hôtes est faible. Elle est plus faible ou tend à l'être chez les faons et les individus âgés de plus de 8 ans et lorsque les populations de chevreuils sont très abondantes par rapport aux ressources disponibles. Les prévalences et les indices parasitaires sont également plus élevés chez les faons et les chevreuils de plus de 8 ans que chez les adultes de 2 à 7 ans, chez les mâles que chez les femelles, en automne qu'en hiver, Lorsque les populations sont abondantes par rapport aux ressources et lorsque les chevreuils sont porteurs de Dictyocaulus noerneri. L'ensemble de nos résultats permet de penser que les parasites peuvent avoir un impact sur la dynamique des populations de chevreuils et en particulier un rôle régulateur. La construction d'un indicateur de la qualité de la relation entre les populations de chevreuils et leur milieu est proposée dans le contexte de la gestion de ces populations.

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Alghanmi, Maimonah. "Identification and therapeutic application of molecular parallels between parasites, parasitic vectors and snake venom." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/17797/.

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Neglected tropical diseases (NTDs) are a group of conditions that exert disability and poverty on populations that comprise the world’s poorest billion people. These conditions, although caused by different organisms and cause distinct disease, they share geographical distribution within tropical regions, occur during similar ecological conditions and most importantly have similar biological mechanisms that are utilized to facilitate the pathology of these diseases. Proteolytic enzymes like proteases are used in many biological mechanisms such as, migration through tissue and cellular compartments; haemoglobin digestion, evasion of immune system responses and cause necrosis and fibrosis to vital tissues and organs. Genomic, transcriptomic, and proteomic studies on parasites (S. mansoni and F. hepatica), parasitic vector (An. gambiae) salivary glands and snake venom show that these diverse pathogens appear to be utilizing similar molecules to perform similar biological mechanisms. Therefore, it is of interest to ascertain whether a cross-cutting approach in research could facilitate a better understanding of these diseases. Therefore, the initial aim of this work was to investigate molecular parallels of the mechanisms used by these tropical disease pathogens, including parasites, snake venom toxins, and haematophagic parasite vectors, to access their host’s blood stream. Using a bioinformatics-led approach, in combination with immunological and proteomic analyses, this study demonstrated the presence of similar compounds between shared molecular molecules (serine proteases and other proteins) causing pathology in parasites, parasitic vectors and snake venom. This similarity was not only at the bioinformatics level, but presence of cross-reactivity toward parasite proteins was detected using antivenoms and toxin-specific antibodies. In addition, sera collected from patients infected with S.mansoni exhibited an immune response to snake venom. One of this study aims was to investigate possibilities of using homologous proteins in parasitic vectors and snake venom as therapeutic applications. For this purpose, chimeric epitopes of homologous snake venom (Echis ocellatus) and mosquito salivary proteins were designed as primary vaccine that could be boosted by mosquito bites. If succeeded, this method would prevent, or at least reduce, the devastating pathology and death caused by snake venom at a low cost, with limited logistical complications.

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Taylor, Mae. "Spiral Valve Parasites of Selected Tropical Pelagic Elasmobranchs and Internal Parasites of Mesopelagic Teleosts." NSUWorks, 2010. http://nsuworks.nova.edu/occ_stuetd/199.

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Natural mortality is a poorly known aspect of fisheries biology, despite its importance in stock assessments and population analysis. Of the many potential sources of mortality and morbidity in fishes, the effect of internal parasites is perhaps the least studied. Intestinal parasites may inhibit nutrient uptake as well as stimulate an inflammatory response in fish. Intestinal parasites of several tropical pelagic elasmobranchs, including silky and night sharks (Carcharhinus falciformis and C. signatus), the pelagic stingray (Pteroplatytrygon violacea), and mesopelagic fishes including sailfin lancetfish (Alepisaurus ferox), oilfish (Ruvettus pretiosus), snake mackerel (Gempylus serpens), escolar (Lepidocybium flavobrunneum), and Atlantic pomfret (Brama brama) are described from the South Atlantic Bight in the western North Atlantic. Parasites recovered include cestodes, trematodes, acanthocephalans and nematodes. Total gastrointestinal parasite loads were compared against the size (both length and weight) of the host, showing no correlation in pelagic elasmobranchs and a small correlation in mesopelagic teleosts. Sex and parasite loads were also compared for elasmobranchs showing a weak correlation. Capture seasons were also compared, and other results of this research showed that the parasites in this study are not host-species specific. The observed parasite classes and total helminth loads are the first described for these five mesopelagic fishes and will serve as a baseline for further studies. Future research is suggested to ascertain if commercially valuable, co-occurring, co-existing pelagic fishes may also be at risk for similar intestinal parasite fauna and burdens.

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Mendonça, Rafael Paranhos de. "Atividade endectocida de uma nova alternativa terapêutica (S-cifenotrina, Butóxido de piperonila, D-tetrametrina e Ivermectina) em cães /." Jaboticabal : [s.n.], 2007. http://hdl.handle.net/11449/95944.

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Orientador: Alvimar José da Costa
Banca: Gilson Pereira de Oliveira
Banca: Luciano Melo de Souza
Resumo: Utilizando-se de delineamentos experimentais apropriados, foi avaliada a atividade endectocida de uma nova associação medicamentosa, composta de dois piretróides (Scifenotrina e D-tetrametrina), butóxido de piperonila e ivermectina. Quatro experimentos foram conduzidos para avaliação terapêutica da nova associação, comparativamente à formulações adquiridas no mercado. Para avaliação carrapaticida e pulicida foram conduzidos dois experimentos. No primeiro ensaio, 21 cães naturalmente infestados por Rhipicephalus sanguineus, selecionados por meio de duas contagens consecutivas, foram randomizados e sorteados em três grupos de sete animais cada. No segundo ensaio, 21 cães selecionados foram randomizados e sorteados, também, em três grupos de sete animais cada. Infestações artificiais foram realizadas nos dias -4, -2, 6, 13, 20, 27 e 34 com Ctenocephalides felis felis (100 pulgas) e nos dias -1, 6, 13, 20, 27 e 34 com R. sanguineus (30 carrapatos). Nos dois experimentos a nova formulação foi comparada à associação D-fenotrina 78,125%+ piriproxifen 2,575%. A eficácia sarnicida da nova formulação experimental, comparativamente à selamectina 12%, foi avaliada em 15 cães naturalmente infestados por S. scabiei var. canis. Raspados cutâneos e avaliações clínicas (regressão das lesões de pele) foram realizados, em todos os cães experimentais. Para avaliação anti-helmíntica, 24 cães foram selecionados por meio de exames coprológicos e distribuídos em três grupos de oito animais cada. As contagens de ovos de nematódeos por grama de fezes (OPG) foram realizadas nos dias -3, -2, -1 (seleção dos animais) e 1, 3, 7, 10 e 14 pós-tratamento. A nova formulação experimental foi comparada à Selamectina 12%.Todos os dados foram avaliados estatisticamente, e as inferências devidamente extraídas...(Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Utilizing of the appropriate experimental design, was evaluated the anti-parasite activity of a new formulation, composed of two piretroids (S-cifenotrin and D-tetrametrin), piperonil butox and ivermectinn. Four experiments had been lead for therapeutical evaluation of the new association, comparativily to the formulation acquired in the market. For the evaluation against ticks and flea, two experiments had been lead. In the first assay, 21 dogs naturally infested by Rhipicephalus sanguineus, selected by means of two consecutive countings, were shuffted and randomly put into three groups of seven animals each. In the second assay, 21 selected dogs were allocated randomly, also, in three groups of seven animals each. Artificial infestations had been carried through in days -4, -2, 6, 13, 20, 27 and 34 with Ctenocephalides felis felis (100 fleas) and in days -1, 6, 13, 20, 27 and 34 with R. sanguineus (30 ticks). In the two experiments the new formulation was compared with the association D-fenotrin 78.125%+ piriproxifen 2.575%. The scabies effectiveness of the new experimental formulation, comparativily to selamectin 12%, was evaluated in 15 dogs naturally infested by S. scabiei var. canis. Cutaneous scrapings and clinical evaluations (regression of the skin injuries) had been carried through, in all the experimental dogs. For antihelmintic evaluation, 24 dogs had been selected by means of the coprology examinations and distributed in three groups of eight animals each. The egg countings of nematodes for gram of fezes (EPG) had been carried through in days -3, -2, -1 (election of the animals) and 1, 3, 7, 10 and 14 post-treatment. The new experimental formulation was compared with the selamectina 12%...(Complete abstract, acess undermentioned eletronic address)
Mestre

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44

Renteria, Flores Axel. "Novel drugs against protozoan parasites." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116979.

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Cryptosporidium parvum and Trypanosoma brucei are two protozoan parasites that can cause life-threatening illnesses in humans. Over 70 million people on the African continent are at risk of contracting T.brucei. In the case of C.parvum, infections are cosmopolitan, and a major problem is that it can be acquired very easily and requires only an infectious dose of 10 oocysts to cause the illness. If released in the public water supplies, C.parvum can endanger entire cities. This is one reason why C.parvum is categorized as a Class B bioterrorist weapon. Despite the threat C.parvum poses and the severe illness T.brucei causes, current treatments against these parasites are insufficient. These treatments fail to consistently eliminate the parasites and cause many adverse side effects. Furthermore, no significant improvements to the efficacy of these currently available treatments have been made. Given the need to find new drugs against these parasites and improve treatments, we tested the anti-parasitic activity of two compounds against T.brucei and C.parvum, respectively. First, we looked at the in vivo activity of TH-III-149, a cyclopropyl-indol, against T. brucei and then the in vitro and in vivo activity of oleyl-PC, a phosphocholine analog, against C. parvum. To begin, we looked at the effects of TH-III-149 against T.brucei by using a CD1 mouse model of infection. We demonstrated that an 8mg/kg treatment of TH-III-149 for three days resulted in a significant decrease in parasite replication rates compared to non-treated mice. By real-time PCR quantification of blood parasitemia, we showed that non-treated, T.brucei-infected mice had a thousand-fold increase in parasite burden between day 2 and 4 of infection. In comparison, only a 7.5-fold increase in parasite burden was observed in mice treated with TH-III-149. Results from blood smears and microscopy also confirmed this reduction in the replication rate of parasites. The treatment of infected mice with TH-III-149 delayed the patent period (appearance of parasites in the blood smear) by two days when compared to non-treated mice. In non-treated mice, parasite in the blood smears appeared at day 4 of the infection, while TH-III-149-treated mice only exhibited parasites in the blood smears at day 6. In addition, this compound showed minimal signs of toxicity, as non-infected mice treated with 8mg/kg of TH-III-149 for three days did not exhibit weight loss, hepatomegaly or splenomegaly. Therefore, our results support the development of TH-III-149 as a new treatment against T.brucei. In parallel, we also tested oleyl-PC against C.parvum. We showed that in vitro oleyl-PC has an IC50 of 22.9nM against C.parvum. Toxicity was evaluated using human ileocecal adenocarcinoma cells (HCT-8 cells) and was not significant at concentrations below 100µM (TC50=153.7 µM). The ratio between the TC50 and the IC50 allowed us to calculate a therapeutic index of 6.7x103. The in vivo animal study confirmed the activity of oleyl-PC previously seen in vitro. Treating C57BL/6 IFNγR-KO mice with 40mg/kg of oleyl-PC for ten days resulted in the cure (clearance of blood parasitemia) in 75% of the mice and a percent survival of 100% after 30 days (P < 0.001). In contrast, all of the non-treated mice succumbed to C. parvum infection and died by day 11. Using real-time PCR, oleyl-PC-treated mice showed no detectable levels of parasitic DNA in their intestines 30 days post infection, which indicates that these mice successfully cleared their parasitic infections. These results were confirmed by histological analysis of sections of the ileum which were clear of C.parvum oocysts. Furthermore, after ten days of treatment with 40mg/kg of oleyl-PC, no signs of toxicity were seen in treated mice; non-infected oleyl-PC-treated mice were monitored for visible behavioral changes and weight loss. Therefore, our results support the development of oleyl-PC as a new safe and effective treatment against C.parvum.
Cryptosporidium parvum et Trypanosoma brucei sont deux parasites protozoaires qui peuvent causer des maladies mortelles chez les humains. Confinées au continent africain, les infections dues à T.brucei affectent plus de 70 millions d'habitants. Dans le cas de C.parvum, les infections qui sont cosmopolites causent un problème majeur puisque la dose infectieuse n'est que de 10 oocysts. De plus, ce parasite peut être obtenu facilement et peut mettre en danger plusieurs villes, s'il est relâché dans les eaux potables. C'est un des raisons pourquoi ce parasite a été catégorisé comme une arme bio-terroriste de classe B. Malgré les risques majeurs associés à C.parvum et la maladie sévère de T.brucei, aucun progrès n'a été fait pour améliorer les traitements actuels. Ceux-ci n'ont toujours pas réussi à démontrer leur efficacité en plus de causer des effets secondaires sérieux. Vu le besoin urgent de trouver de meilleurs traitements, nous avons testé l'activité de TH-III-149, un indole-cyclopropane, contre T.brucei dans une étude in vivo ainsi que le oleyl-PC, un analogue de la phosphocholine, contre C.parvum dans des études in vitro et in vivo. Pour commencer, nous avons observé les effets du TH-III-149 contre T.brucei dans un modèle de souris CD1. Les résultats in vivo ont démontré qu'un traitement de trois jours en utilisant 8 mg/kg cause une réduction significative dans le taux de réplication du parasite en comparaison aux souris non-traitées. En utilisant le PCR en temps réel comme méthode de quantification, nous avons démontré que la charge en parasite dans le sang des souris non-traitées a augmenté de mille fois entre les jours 2 et 4, tandis qu'elle n'a augmenté que de 7.5 fois dans les souris qui ont été traitées. Les résultats des frottis sanguins ont confirmé cette réduction dans le taux de réplication des parasites. En effet, l'apparition de parasites dans les frottis sanguins a été observée dès le jour 4 de l'infection dans les souris non-traitées, tandis qu'elle n'a pu être observée qu'à partir du jour 6 dans les souris traitées avec le TH-III-149. De plus, ce composé n'a pas révélé de signes de toxicité car les groupes de souris non-infectées traitées pendant trois jours avec 8 mg/kg n'ont pas démontré de splénomégalie, d'hépatomégalie ni de perte de poids. Donc, nos résultats supportent le développement de TH-III-149 en tant que nouveau traitement contre les infections de T.brucei. En parallèle, nous avons aussi testé l'oleyl-PC contre C.parvum. Nos résultats in vitro démontrent que la concentration nécessaire pour réduire de 50% le taux de réplication du parasite (IC50) est de 25nM. La toxicité a été évaluée en utilisant une culture entérique humaine en couche monocellulaire (HCT-8). Les résultats de celle-ci démontrent que les premiers signes de toxicité apparaissent à partir de 100µM (TC50=123µM). Le ratio entre le TC50 et le IC50 a permis de calculer un index thérapeutique de 5x103. Les résultats in vivo ont servis à confirmer l'activité in vitro de oleyl-PC. En effet, le traitement de dix jours des souris C57BL/6 IFNγR-KO avec 40mg/kg de oleyl-PC a réussi à guérir (absence de parasitémie sanguine) 75% des souris, tout en gardant un taux de survie de 100% après le jour 30 (P<0.001). En contraste, toutes les souris non-traitées ont succombées à l'infection à la fin du jour 11. En utilisant le PCR en temps réel, aucune trace d'ADN provenant de C.parvum n'a pu être détectée dans les intestins de ces souris 30 jours après l'infection. Ces résultats ont été confirmés par l'analyse des lamelles histologique de l'ilium de ces souris où l'absence d'oocyst de C.parvum a été observée. De plus, chez les souris non-infectées, un traitement de dix jours avec 40 mg/kg de oleyl-PC n'a pas causé d'effets secondaires visibles tels qu'une perte de poids. Donc, nos résultats supportent le développement de l'oleyl-PC en tant que nouveau traitement sécuritaire et efficace contre les infections de C.parvum.

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45

Halliday, Aileen. "Ruminant immunity to abomasal parasites." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8804.

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The studies submitted herein have contributed to our understanding of ruminant immunology, host-parasite interactions during ruminant infection with nematode parasites, and potential vaccine strategies to combat parasitic gastroenteritis (PGE). PGE of sheep and cattle, caused by T. circumcincta and O. ostertagia respectively, is a major problem for the global farming industry both in terms of productivity and animal welfare. To date control of these parasites has relied on the use of anthelmintic drugs however the emergence of widespread anthelmintic resistance is driving the search for alternative methods of control. As ruminants do acquire immunity in the field, vaccination is one such alternative under investigation. The first three papers contributing to this thesis used modern immunological tools alongside a locally developed surgical technique to revisit a model of nematode infection in sheep, investigating the composition and kinetics of the ovine local immune response to infection with Teladorsagia circumcincta via cannulation of the efferent gastric lymph duct. A protective local secondary immune response was observed in sheep which had previously experienced infection with T. circumcincta, but was absent from naive sheep. This immune response consisted initially of a rise in TE and BE cell activity peaking at 3 and 5 days post challenge respectively, followed by a secondary parasiteEspecific IgA response from 5 days post challenge which correlated with stunting of parasite growth. Significant parasite loss occurred by 2 days post challenge, prior to detection of the secondary immune response, suggesting critical early events in the host-parasite interaction and the potential importance of larval antigens in these interactions. No difference was observed in either the manifestations of immunity, or the magnitude and quality of the immune response, between adult sheep and lambs. The fourth and fifth papers describe vaccine trials carried out in bovine and ovine hosts using detergent soluble proteins derived from 4th larval stage Ostertagia ostertagi and Teladorsagia circumcincta respectively as antigens. Substantial reduction in total faecal egg output of up to 85% was observed in the calf trials, but not in the sheep trials which attained a maximum reduction of 29% in total faecal egg output. The sixth paper is a transcriptomic study carried out using the Roche 454 sequencing platform to investigate the immediate responses of Teladorsagia circumcincta upon encountering ovine host tissue of either immune or naive status. Following larval exsheathing and 4 hours of exposure to either immune or naive abomasal environments the transcript level of several genes was observed to differ. Genes which were most upregulated in response to encountering the immune environment included a peptidyl-glycine alpha-amidating mono-oxygenase homologue and a small heat shock protein. The studies described herein represent a body of work carried out using up-to-date tools and technologies. The first three papers confirmed the existence of critical early events in the host-parasite interaction, pointing to the potential use of larval antigens as vaccine candidates described in the trials in papers 4 and 5, and leading to the in-depth transcriptomic analysis described in paper 6. Papers 4 and 5 demonstrated that while Teladorsagia circumcincta and Ostertagia ostertagi have similar life cycles and host-site predilection, and both the ovine and bovine host can develop immunity to incoming parasitic larvae in the field, important differences may exist in either the proteome of the fourth stage larvae and/or the nature of the host response. Paper 6 revealed that changes in T. circumcincta transcript levels in response to ovine-host immune status can be detected early in the host-parasite interaction.

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46

Mackinnon, Margaret J. "Evolutionary genetics of malaria parasites." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/15243.

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Two empirical studies on parasite virulence using the laboratory model of the rodent malaria parasite, Plasmodium chabaudi, in inbred mice, were conducted. In the first, the average virulence and transmissibility in eight parasite clones obtained from the wild were measured over four replicate experiments. Large amounts of genetic (between-clone) variation in virulence and transmissibility were observed. Virulence was strongly correlated, both phenotypically and genetically, to population growth rate (parasitaemia) and less strongly correlated to transmissibility. These results provide strong support for the basic tenet of most evolutionary models of parasite virulence, namely, that virulence is a by-product of the parasite's need to replicate fast in order to be transmitted. In the second study, between-host selection for high and low virulence was performed within two parasite clones. Over eleven generations, all the selection lines increased in virulence and transmissibility. Thus, despite artificial between-host selection, parasitic variation within clones coupled with inadvertent within-host selection, allowed the parasite to adapt to a novel host. Together, these studies show that virulence is strongly determined by parasite genetics. A large data set on disease severity from a 3-year longitudinal field study in Sri Lanka was analysed for the effects of host genetic variability, age, immune experience, parasite species (P. falciparum vs. P. vivax), bednet use, sex and other host or environmental factors. The results highlighted the importance of short-term acquired immunity in causing large between-host variation in virulence. This is consistent with the view that parasite variability is responsible for inefficient clinical immunity to malarial disease, although this could not be examined directly and alternative explanations are possible. Two theoretical models incorporating parasite population structure into population genetics were used to predict the probability and rate of evolution of multi-locus drug resistance. All of these studies suggest that parasite genetic variation plays a key role in the evolution of the malaria host-parasite association.

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47

Servel, Grégory. "Effets parasites dus aux interconnexions." Montpellier 2, 2001. http://www.theses.fr/2001MON20037.

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48

Alkhaldi, Abdulsalam Abdulhadi. "Drug development against kinetoplastid parasites." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3637/.

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Human African trypanosomiasis and leishmaniasis are caused by parasites belonging to the genera Trypanosoma and Leishmania, respectively. Significant numbers of people are affected by these diseases worldwide, which are fatal if untreated. Animals can also be infected, posing agricultural and economic hindrances, especially in poor countries. Although chemotherapy can be used for treatment, many problems are associated with it, including drug toxicity, resistance, lack of guaranteed supply, and high treatment cost. Therefore, there is an urgent need for new treatment approaches. Here, we aim to examine the in vitro efficacy of curcumin and phosphonium compounds against these parasites, assay their toxicity to human kidney cells in vitro, and investigate the mechanism of antiparasite activity of curcumin. The Alamar blue assay was used to test 158 curcumin analogues against Leishmania major promastigotes and Leishmania mexicana promastigotes and axenic amastigotes to obtain in vitro EC50 values. Many curcumin compounds such as AS-HK122 and AS-HK126 exhibited anti-leishmanial activities similar to or better than the current clinical drug pentamidine. Similarly, EC50 values of 83 phosphonium compounds against Trypanosoma brucei brucei bloodstream forms were determined. More than 20% of the tested compounds were found to be more active than the standard veterinary drug diminazene aceturate. Multi-drug resistant strains were used to determine that there is no cross-resistance between the tested compounds and the diamidine or melaminophenyl arsenical classes of trypanocides. Structure activity relationship (SAR) analysis revealed that mono-O-demethylated curcumin compounds showed 10-fold higher activity against the parasites than curcumin. The addition of one or two pentyl pyridinium (C10H15N) groups on specific positions of the aromatic ring also increased the activity of these compounds. Furthermore, curcumin compounds with an isoxazole ring instead of the diketo motif showed higher activity and the lowest EC50 values. Similarly, pentyl bromide (OC5H10Br) substitutions on the phenyl rings improved the antiparasitic activity. Curcuminoids with trienone linkers showed increased antiparasitic activity against all parasites tested. Eighty-three phosphonium analogues were tested against T. brucei brucei. SAR analysis indicated that the bulky substituents surrounding the bisphosphonium cations led to strong antiparasitic activity while the nature of the linker had less effect on the activity. Some monophosphonium analogues registered the lowest EC50 values of all the phosphonium compounds. The toxicity of the curcumin and phosphonium analogues to HEK cells was analysed in vitro. All curcumin and phosphonium compounds demonstrated lower toxicity to HEK cells than to the parasites. Of the 83 phosphonium compounds, 60 displayed >200-fold in vitro selectivity index (SI). We also investigated the mode of antiparasitic activity of curcumin compounds. Preliminary toxicity tests had revealed that AS-HK014 caused rapid depletion of glutathione content in rat hepatocytes. Therefore, we tested AS-HK014 activity in the presence of different concentrations of L-glutathione, and AS-HK014 activity was found to decrease with increased L-glutathione concentrations, strongly suggesting that glutathione reacted with the active compound. Indeed, a chemical adduct was observed between the two compounds and identified through mass spectrometry. A trypanosome cell line (TA014) adapted to AS-HK014 was produced. TA014 and wild-type T. brucei brucei were treated with AS-HK014 and compared with each other and with untreated controls. The glutathione and trypanothione levels were lower in the treated WT cells than in the untreated cells. However, there was no change in the glutamate, ornithine, or spermidine levels, providing no evidence for the inhibition of trypanothione synthesis, suggesting that the effect is probably not metabolic but chemical. AS-HK014 did not significantly affect thiol levels in TA014; this might reflect a higher level of trypanothione synthesis through increased glutathione synthetase (GS) and/or γ-glutamylcysteine synthetase (γ-GCS) expression. Therefore, we analysed the protein levels using western blotting, and sequenced the encoding genes in both WT and TA014 to identify any mutations in the open reading frames (ORFs). However, we found no changes in the GS and γ-GCS protein levels in resistant trypanosomes and no mutations were found in the GS and γ-GCS ORFs. It is clear that the resistance is to the reactive enone motif of AS-HK014 rather than to curcumin and curcuminoids in general, since TA014 only displayed resistance to AS-HK014 analogues bearing the enone motif while sensitivity to curcumin remained unchanged, confirming that this motif is responsible for the higher activity of AS-HK014 compared to curcumin. The effects of bisphosphonium analogues on T. brucei brucei bloodstream forms were investigated to identify the target. All tested analogues rapidly reduced the T. brucei brucei mitochondrial membrane potential Ψm and decreased the intracellular ATP level after one hour of incubation, suggesting that the compounds may be targeting the mitochondria. The intracellular Ca2+ levels increased gradually after eight hours, suggesting that the damaged mitochondria are unable to retain the stored Ca2+ as their membrane potential dissipates. We also studied the trypanosome cell cycle after incubating the parasites with bisphosphonium compounds. The cell cycle defects became apparent after eight hours of incubation: DNA synthesis could not be initiated, leading to a dramatic reduction of cells in the S phase. This result was also confirmed by fluorescence microscopic assessment of DNA configuration. After eight hours of incubation with the bisphosphonium compound CD38, the number of 2K1N cells significantly decreased as compared with the control. There may be a causal relationship between mitochondrial damage and cell cycle defects. Transmission electron microscopy images of the cells obtained after 12 h of exposure to CD38 also revealed the presence of mitochondrial damage. We tested whether bisphosphonium compounds can induce programmed cell death in trypanosomes. A TUNEL assay was used to detecting DNA fragmentation; the results showed increased DNA fragmentation after 24-h treatment with two different bisphosphonium compounds, CD38 and EFpI7. This result indicates is consistent with apoptosis occurring in treated cells but there was no evidence suggesting that bisphosophonium-induced cell death in trypanosomes is dependent on new protein synthesis. In conclusion, curcumin and phosphonium analogues exhibit promising antiparasitic activity, and some analogues could be optimised for in vivo evaluation. Further investigations on the site of action of phosphonium compounds in the mitochondrion are in progress.

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49

Brewster, Bernice. "Aquatic Parasite Information : a database on parasites of freshwater and brackish fish in the United Kingdom." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/39278/.

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A checklist of parasites of freshwater fish in the UK is an important source of information concerning hosts and their distribution for all aspects of scientific research. An interactive, electronic, web-based databse, Aquatic Parasite Information has been designed, incorporating all freshwater and brackish species of fish, parasites, taxonomy, synonyms, authors and associated hosts, together with records for their distribution. One of the key features of Aquatic Parasite Information is this checklist can be updated. Interrogation of Aquatic Parastie Information has revealed that some parasites of freshwater and brackish species of fish, such as the unicellular groups or those metzoans that are difficult to identify using morphological characters, are under reported. Aquatic Parasite Information identified the monogenean family Dactylogyridae and the cestodes infecting UK freshwater fish as under-represented groups, owing to the difficulties identifying them morphologically. Both the Dactylogyridae and cestodes have implications for pathology, outbreaks of disease and morbidity in freshwater fish in the UK, therefore accurate identification is critical. Studies were undertaken using both standard morphological techniques of histology and molecular techniques to identify dactylogyrid species and tapeworms commonly found parasitizing fish in the UK. Morphological studies demonstrated that histological processes could lead to distortion of the specimins and permanent mounting may affect the orientation which may obscure vital characteristics. Moleculr techniques were successfully employed using ITS1 for the Dactylogyridae and cox1 and r28s for the cestodes, to demonstrate genetic variability for the interspecific identification of species. Histology, scanning electron microscopy and molecular techniques have also identified an Atractolytocestus sp. tapeworm, parasitizing carp in the UK, as a potentially new species. Analysis of parasite records extracted from Aquatic Parasite Information has implicated freshwater fishery management policies as impacting on the dissemination and distribution of parasites, resulting in the spread of some species and decline of others.

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50

Lester, Hannah. "Anthelmintic resistance in equine parasites : an epidemiological approach to build a framework for sustainable parasite control." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2029559/.

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Faecal egg count (FEC) directed targeted anthelmintic treatment programmes and regular efficacy testing using the faecal egg count reduction test (FECRT) have been advocated to support evidence-based helminth control in horses. One major hurdle to their widespread application is that horse owners/managers and those that prescribe anthelmintics may have insufficient knowledge on which to base evidence-based protocols. The ultimate aim of this study was to create a framework for a decision support system (DSS) to support evidence-based helminth control in horses. To create the framework, the diagnostic performance of FEC and FECRT methodologies were evaluated. In addition, the efficacy of the three licensed anthelmintic classes was tested in several equine populations. The prevalence and distribution of helminths was determined in these populations, and an analysis undertaken to investigate factors associated with different levels of strongyle egg shedding in individuals. The consistency of egg shedding patterns in individuals over time was evaluated and the resource implications of following a FEC directed targeted treatment investigated. The FEC analysis findings support the rationale of FEC directed targeted anthelmintic treatments in horses to reduce treatment frequency in order to mitigate the impact of anthelmintic resistance. Moreover, the results show that such a strategy may be cost effective. The efficacy studies revealed that the macrocyclic lactone anthelmintics were highly effective in reducing strongyle egg output at two weeks after treatment, but further studies are required to analyse the strongyle egg reappearance period after treatment with these anthelmintics. In summary, this study validates the use of FEC directed treatment protocols in the field and the next step will be to use the derived information to design user-friendly online support tools.

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Dissertations / Theses on the topic 'Parasites'

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