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1
MUÑOZ, G., A. S. GRUTTER e T. H. CRIBB. "Endoparasite communities of five fish species (Labridae: Cheilininae) from Lizard Island: how important is the ecology and phylogeny of the hosts?" Parasitology 132, n. 3 (7 dicembre 2005): 363–74. http://dx.doi.org/10.1017/s0031182005009133.
Testo completoAbstract (sommario):
The parasite community of animals is generally influenced by host physiology, ecology, and phylogeny. Therefore, sympatric and phylogenetically related hosts with similar ecologies should have similar parasite communities. To test this hypothesis we surveyed the endoparasites of 5 closely related cheilinine fishes (Labridae) from the Great Barrier Reef. They were Cheilinus chlorourus, C. trilobatus, C. fasciatus, Epibulus insidiator and Oxycheilinus diagramma. We examined the relationship between parasitological variables (richness, abundance and diversity) and host characteristics (body weight, diet and phylogeny). The 5 fishes had 31 parasite species with 9–18 parasite species per fish species. Cestode larvae (mostly Tetraphyllidea) were the most abundant and prevalent parasites followed by nematodes and digeneans. Parasites, body size and diet of hosts differed between fish species. In general, body weight, diet and host phylogeny each explained some of the variation in richness and composition of parasites among the fishes. The 2 most closely related species, Cheilinus chlorourus and C. trilobatus, had broadly similar parasites but the other fish species differed significantly in all variables. However, there was no all-encompassing pattern. This may be because different lineages of parasites may react differently to ecological variables. We also argue that adult parasites may respond principally to host diet. In contrast, larval parasite composition may respond both to host diet and predator-prey interactions because this is the path by which many parasites complete their life-cycles. Finally, variation in parasite phylogeny and parasite life-cycles among hosts likely increase the complexity of the system making it difficult to find all-encompassing patterns between host characteristics and parasites, particularly when all the species in rich parasite communities are considered.
2
Marques, Livia Castro, e Dimitri Ramos Alves. "Ecologia da comunidade de metazoários parasitos do dourado, Coryphaena hippurus Linnaeus, 1758, (Osteichthyes: Coryphaenidae) do litoral do Estado do Rio de Janeiro, Brasil." Cadernos UniFOA 6, n. 16 (27 marzo 2017): 111. http://dx.doi.org/10.47385/cadunifoa.v6i16.1070.
Testo completoAbstract (sommario):
From April 2009 and July 2010, 68 specimens of common dolphinfish Coryphaena hippurus Linnaeus, 1758 (Osteichthyes: Coryphaenidae) collected from coast of the state of Rio de Janeiro (21-23° S, 41-45° W), were necropsied to study their infracommunities of metazoan parasites. Seventeen species of metazoan parasites were collected. All fish were parasitized by one or more metazoan. The digeneans were the majority of the specimens collected, with 90.7%. Dinurus tornatus (Rudolphi, 1819) was the dominant species with highest abundance, prevalence, frequency of dominance and mean relative dominance. The parasites species of C. hippurus showed a typical aggregate pattern of distribution. None metazoan parasites species showed correlation between total length and prevalence and parasite abundance. The metazoan parasite infracommunities C. hippurus showed dominance of endoparasites (digeneans) and no correlation between abundance and parasite species richness and the total length of the host.
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Marques, Livia Castro, e Dimitri Ramos Alves. "Ecologia da comunidade de metazoários parasitos do dourado, Coryphaena hippurus Linnaeus, 1758, (Osteichthyes: Coryphaenidae) do litoral do Estado do Rio de Janeiro, Brasil." Cadernos UniFOA 6, n. 16 (27 marzo 2017): 111–22. http://dx.doi.org/10.47385/cadunifoa.v6.n16.1070.
Testo completoAbstract (sommario):
From April 2009 and July 2010, 68 specimens of common dolphinfish Coryphaena hippurus Linnaeus, 1758 (Osteichthyes: Coryphaenidae) collected from coast of the state of Rio de Janeiro (21-23° S, 41-45° W), were necropsied to study their infracommunities of metazoan parasites. Seventeen species of metazoan parasites were collected. All fish were parasitized by one or more metazoan. The digeneans were the majority of the specimens collected, with 90.7%. Dinurus tornatus (Rudolphi, 1819) was the dominant species with highest abundance, prevalence, frequency of dominance and mean relative dominance. The parasites species of C. hippurus showed a typical aggregate pattern of distribution. None metazoan parasites species showed correlation between total length and prevalence and parasite abundance. The metazoan parasite infracommunities C. hippurus showed dominance of endoparasites (digeneans) and no correlation between abundance and parasite species richness and the total length of the host.
4
Ezenwa, Vanessa O., Elizabeth A. Archie, Meggan E. Craft, Dana M. Hawley, Lynn B. Martin, Janice Moore e Lauren White. "Host behaviour–parasite feedback: an essential link between animal behaviour and disease ecology". Proceedings of the Royal Society B: Biological Sciences 283, n. 1828 (13 aprile 2016): 20153078. http://dx.doi.org/10.1098/rspb.2015.3078.
Testo completoAbstract (sommario):
Animal behaviour and the ecology and evolution of parasites are inextricably linked. For this reason, animal behaviourists and disease ecologists have been interested in the intersection of their respective fields for decades. Despite this interest, most research at the behaviour–disease interface focuses either on how host behaviour affects parasites or how parasites affect behaviour, with little overlap between the two. Yet, the majority of interactions between hosts and parasites are probably reciprocal, such that host behaviour feeds back on parasites and vice versa. Explicitly considering these feedbacks is essential for understanding the complex connections between animal behaviour and parasite ecology and evolution. To illustrate this point, we discuss how host behaviour–parasite feedbacks might operate and explore the consequences of feedback for studies of animal behaviour and parasites. For example, ignoring the feedback of host social structure on parasite dynamics can limit the accuracy of predictions about parasite spread. Likewise, considering feedback in studies of parasites and animal personalities may provide unique insight about the maintenance of variation in personality types. Finally, applying the feedback concept to links between host behaviour and beneficial, rather than pathogenic, microbes may shed new light on transitions between mutualism and parasitism. More generally, accounting for host behaviour–parasite feedbacks can help identify critical gaps in our understanding of how key host behaviours and parasite traits evolve and are maintained.
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Auld, Stuart K. J. R., Catherine L. Searle e Meghan A. Duffy. "Parasite transmission in a natural multihost–multiparasite community". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1719 (13 marzo 2017): 20160097. http://dx.doi.org/10.1098/rstb.2016.0097.
Testo completoAbstract (sommario):
Understanding the transmission and dynamics of infectious diseases in natural communities requires understanding the extent to which the ecology, evolution and epidemiology of those diseases are shaped by alternative hosts. We performed laboratory experiments to test how parasite spillover affected traits associated with transmission in two co-occurring parasites: the bacterium Pasteuria ramosa and the fungus Metschnikowia bicuspidata . Both parasites were capable of transmission from the reservoir host ( Daphnia dentifera ) to the spillover host ( Ceriodaphnia dubia ), but this occurred at a much higher rate for the fungus than the bacterium. We quantified transmission potential by combining information on parasite transmission and growth rate, and used this to compare parasite fitness in the two host species. For both parasites, transmission potential was lower in the spillover host. For the bacterium, virulence was higher in the spillover host. Transmission back to the original host was high for both parasites, with spillover influencing transmission rate of the fungus but not the bacterium. Thus, while inferior, the spillover host is not a dead-end for either parasite. Overall, our results demonstrate that the presence of multiple hosts in a community can have important consequences for disease transmission, and host and parasite fitness. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.
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Horn, Collin J., e Lien T. Luong. "Proximity to parasites reduces host fitness independent of infection in a Drosophila–Macrocheles system". Parasitology 145, n. 12 (13 marzo 2018): 1564–69. http://dx.doi.org/10.1017/s0031182018000379.
Testo completoAbstract (sommario):
AbstractParasites are known to have direct negative effects on host fitness; however, the indirect effects of parasitism on host fitness sans infection are less well understood. Hosts undergo behavioural and physiological changes when in proximity to parasites. Yet, there is little experimental evidence showing that these changes lead to long-term decreases in host fitness. We aimed to determine if parasite exposure affects host fitness independent of contact, because current approaches to parasite ecology may underestimate the effect of parasites on host populations. We assayed the longevity and reproductive output of Drosophila nigrospiracula exposed or not exposed to ectoparasitic Macrocheles subbadius. In order to preclude contact and infection, mites and flies were permanently separated with a mesh screen. Exposed flies had shorter lives and lower fecundity relative to unexposed flies. Recent work in parasite ecology has argued that parasite–host systems show similar processes as predator–prey systems. Our findings mirror the non-consumptive effects observed in predator–prey systems, in which prey species suffer reduced fitness even if they never come into direct contact with predators. Our results support the perspective that there are analogous effects in parasite–host systems, and suggest new directions for research in both parasite ecology and the ecology of fear.
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Sarabian, Cecile, Val Curtis e Rachel McMullan. "Evolution of pathogen and parasite avoidance behaviours". Philosophical Transactions of the Royal Society B: Biological Sciences 373, n. 1751 (4 giugno 2018): 20170256. http://dx.doi.org/10.1098/rstb.2017.0256.
Testo completoAbstract (sommario):
All free-living animals are subject to intense selection pressure from parasites and pathogens resulting in behavioural adaptations that can help potential hosts to avoid falling prey to parasites. This special issue on the evolution of parasite avoidance behaviour was compiled following a Royal Society meeting in 2017. Here we have assembled contributions from a wide range of disciplines including genetics, ecology, parasitology, behavioural science, ecology, psychology and epidemiology on the disease avoidance behaviour of a wide range of species. Taking an interdisciplinary and cross-species perspective allows us to sketch out the strategies, mechanisms and consequences of parasite avoidance and to identify gaps and further questions. Parasite avoidance strategies must include avoiding parasites themselves and cues to their presence in conspecifics, heterospecifics, foods and habitat. Further, parasite avoidance behaviour can be directed at constructing parasite-retardant niches. Mechanisms of parasite avoidance behaviour are generally less well characterized, though nematodes, rodents and human studies are beginning to elucidate the genetic, hormonal and neural architecture that allows animals to recognize and respond to cues of parasite threat. While the consequences of infection are well characterized in humans, we still have much to learn about the epidemiology of parasites of other species, as well as the trade-offs that hosts make in parasite defence versus other beneficial investments like mating and foraging. Finally, in this overview we conclude that it is legitimate to use the word ‘ disgust' to describe parasite avoidance systems, in the same way that ‘fear' is used to describe animal predator avoidance systems. Understanding disgust across species offers an excellent system for investigating the strategies, mechanisms and consequences of behaviour and could be a vital contribution towards the understanding and conservation of our planet's ecosystems. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours'.
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Grenfell, B. T., e F. M. D. Gulland. "Introduction: Ecological impact of parasitism on wildlife host populations". Parasitology 111, S1 (gennaio 1995): S3—S14. http://dx.doi.org/10.1017/s0031182000075788.
Testo completoAbstract (sommario):
The study of parasite population dynamics has been one of the major developments in ecology over the last 15 years (Kennedy, 1975). The seminal articles of Crofton (1971) and Anderson & May (1978, 1979; May & Anderson, 1978, 1979) began this process by illustrating the potential role of parasites in regulating or destabilizing the dynamics of wildlife host populations. Since then, a variety of empirical and theoretical studies (reviewed by Grenfell & Dobson, 1995) have explored the role of parasites in natural populations. In parallel with these population dynamical developments, a growing interest in the evolutionary ecology of parasites has also led to a large literature, examining the evolutionary impact of parasites and the importance of host-parasite coevolution (Hamilton, 1982; May & Anderson, 1990; Lively & Apanius, 1995; Read et al. 1995; Herre, this volume).
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Mahony, Kate E., Sharon A. Lynch, Xavier de Montaudouin e Sarah C. Culloty. "Extrinsic and intrinsic drivers of parasite prevalence and parasite species richness in a marine bivalve". PLOS ONE 17, n. 9 (26 settembre 2022): e0274474. http://dx.doi.org/10.1371/journal.pone.0274474.
Testo completoAbstract (sommario):
Parasite species richness is influenced by a range of drivers including host related factors (e.g. host size) and environmental factors (e.g. seawater temperature). However, identification of modulators of parasite species richness remains one of the great unanswered questions in ecology. The common cockle Cerastoderma edule is renowned for its diversity and abundance of parasites, yet drivers of parasite species richness in cockles have not been examined to investigate the association of both macro and microparasite communities. Using cockles as a model species, some of the key drivers of parasite prevalence and parasite species richness were investigated. Objectives of this 19-month survey were to determine the influence of the environment, host-parasite dynamics and parasite associations on parasite species richness and prevalence at two different geographic latitudes, chosen based on environmental differences. The highest parasite species richness was recorded in the northern sites, and this was potentially influenced by a range of interactions between the host, the pathogens and the environment. Parasite prevalence increased with host size and age, and parasite species richness increased with reduced salinity. A number of interactions between parasites, and between parasites and pathologies may be influencing parasite infection dynamics. New and concerning information is also presented regarding interactions between parasites and their environment. A number of parasites and potential pathogens (bacteria, Trichodina ciliates, metacercariae, trematode sporocysts) may be advantaged under climate change conditions (warming seas, increased precipitation), increasing disease incidence, which may prove detrimental not just for cockles, but for other bivalve species in the future.
10
Walker, Josephine G., Michaela Plein, Eric R. Morgan e Peter A. Vesk. "Uncertain links in host–parasite networks: lessons for parasite transmission in a multi-host system". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1719 (13 marzo 2017): 20160095. http://dx.doi.org/10.1098/rstb.2016.0095.
Testo completoAbstract (sommario):
For many parasites, the full set of hosts that are susceptible to infection is not known, and this could lead to a bias in estimates of transmission. We used counts of individual adult parasites from historical parasitology studies in southern Africa to map a bipartite network of the nematode parasites of herbivore hosts that occur in Botswana. Bipartite networks are used in community ecology to represent interactions across trophic levels. We used a Bayesian hierarchical model to predict the full set of host–parasite interactions from existing data on parasitic gastrointestinal nematodes of wild and domestic ungulates given assumptions about the distribution of parasite counts within hosts, while accounting for the relative uncertainty of less sampled species. We used network metrics to assess the difference between the observed and predicted networks, and to explore the connections between hosts via their shared parasites using a host–host unipartite network projected from the bipartite network. The model predicts a large number of missing links and identifies red hartebeest, giraffe and steenbok as the hosts that have the most uncertainty in parasite diversity. Further, the unipartite network reveals clusters of herbivores that have a high degree of parasite sharing, and these clusters correspond closely with phylogenetic distance rather than with the wild/domestic boundary. These results provide a basis for predicting the risk of cross-species transmission of nematode parasites in areas where livestock and wildlife share grazing land. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.
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Cizauskas, Carrie A., Colin J. Carlson, Kevin R. Burgio, Chris F. Clements, Eric R. Dougherty, Nyeema C. Harris e Anna J. Phillips. "Parasite vulnerability to climate change: an evidence-based functional trait approach". Royal Society Open Science 4, n. 1 (gennaio 2017): 160535. http://dx.doi.org/10.1098/rsos.160535.
Testo completoAbstract (sommario):
Despite the number of virulent pathogens that are projected to benefit from global change and to spread in the next century, we suggest that a combination of coextinction risk and climate sensitivity could make parasites at least as extinction prone as any other trophic group. However, the existing interdisciplinary toolbox for identifying species threatened by climate change is inadequate or inappropriate when considering parasites as conservation targets. A functional trait approach can be used to connect parasites' ecological role to their risk of disappearance, but this is complicated by the taxonomic and functional diversity of many parasite clades. Here, we propose biological traits that may render parasite species particularly vulnerable to extinction (including high host specificity, complex life cycles and narrow climatic tolerance), and identify critical gaps in our knowledge of parasite biology and ecology. By doing so, we provide criteria to identify vulnerable parasite species and triage parasite conservation efforts.
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DALLAS, TAD, ANDREW W. PARK e JOHN M. DRAKE. "Predictability of helminth parasite host range using information on geography, host traits and parasite community structure". Parasitology 144, n. 2 (20 ottobre 2016): 200–205. http://dx.doi.org/10.1017/s0031182016001608.
Testo completoAbstract (sommario):
SUMMARYHost–parasite associations are complex interactions dependent on aspects of hosts (e.g. traits, phylogeny or coevolutionary history), parasites (e.g. traits and parasite interactions) and geography (e.g. latitude). Predicting the permissive host set or the subset of the host community that a parasite can infect is a central goal of parasite ecology. Here we develop models that accurately predict the permissive host set of 562 helminth parasites in five different parasite taxonomic groups. We developed predictive models using host traits, host taxonomy, geographic covariates, and parasite community composition, finding that models trained on parasite community variables were more accurate than any other covariate group, even though parasite community covariates only captured a quarter of the variance in parasite community composition. This suggests that it is possible to predict the permissive host set for a given parasite, and that parasite community structure is an important predictor, potentially because parasite communities are interacting non-random assemblages.
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Legas, Mohammed Seid. "THE ECOLOGICAL HOSTS SHIFT OF PARASITES AND THE OUTBREAK OF EMERGING INFECTIOUS DISEASES: A REVIEW". International Journal of Research -GRANTHAALAYAH 5, n. 8 (31 agosto 2017): 104–8. http://dx.doi.org/10.29121/granthaalayah.v5.i8.2017.2189.
Testo completoAbstract (sommario):
Parasites are organisms which metabolically depend upon their hosts. To understand the ecological host shift of a parasite, it is important to look the host-parasite associations with respect to ecological change and factors that generate, maintain, and constrain the associations with implications for a wide range of ecological issues, including the dynamics of emerging infectious diseases. Although, the ecological significance of parasites is almost overlooked for several years by ecologists, considerable efforts are being made to understand their functional importance in ecosystems. Parasites play vital role in the trophic cascades of the food web. Environmental change caused by anthropogenic activities result host shift of specialist parasites and this shift of specialized parasites can rapidly to new hosts via ecological fitting play an important role in the ecology and evolution of host-parasite associations. This condition is the primary cause for the Emerging Infectious Diseases when parasite species begin infecting and causing disease in host species with which they have no previous history of association. Therefore, understanding the host parasites interaction and distribution of known and potential pathogens is a vital precondition for optimizing their positive, while minimizing their negative effects on conservation, restoration and sustained development programs.
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Farrell, Maxwell J., Andrew W. Park, Clayton E. Cressler, Tad Dallas, Shan Huang, Nicole Mideo, Ignacio Morales-Castilla, T. Jonathan Davies e Patrick Stephens. "The ghost of hosts past: impacts of host extinction on parasite specificity". Philosophical Transactions of the Royal Society B: Biological Sciences 376, n. 1837 (20 settembre 2021): 20200351. http://dx.doi.org/10.1098/rstb.2020.0351.
Testo completoAbstract (sommario):
A growing body of research is focused on the extinction of parasite species in response to host endangerment and declines. Beyond the loss of parasite species richness, host extinction can impact apparent parasite host specificity, as measured by host richness or the phylogenetic distances among hosts. Such impacts on the distribution of parasites across the host phylogeny can have knock-on effects that may reshape the adaptation of both hosts and parasites, ultimately shifting the evolutionary landscape underlying the potential for emergence and the evolution of virulence across hosts. Here, we examine how the reshaping of host phylogenies through extinction may impact the host specificity of parasites, and offer examples from historical extinctions, present-day endangerment, and future projections of biodiversity loss. We suggest that an improved understanding of the impact of host extinction on contemporary host–parasite interactions may shed light on core aspects of disease ecology, including comparative studies of host specificity, virulence evolution in multi-host parasite systems, and future trajectories for host and parasite biodiversity. This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.
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Herrera, James, e Charles L. Nunn. "Behavioural ecology and infectious disease: implications for conservation of biodiversity". Philosophical Transactions of the Royal Society B: Biological Sciences 374, n. 1781 (29 luglio 2019): 20180054. http://dx.doi.org/10.1098/rstb.2018.0054.
Testo completoAbstract (sommario):
Behaviour underpins interactions among conspecifics and between species, with consequences for the transmission of disease-causing parasites. Because many parasites lead to declines in population size and increased risk of extinction for threatened species, understanding the link between host behaviour and disease transmission is particularly important for conservation management. Here, we consider the intersection of behaviour, ecology and parasite transmission, broadly encompassing micro- and macroparasites. We focus on behaviours that have direct impacts on transmission, as well as the behaviours that result from infection. Given the important role of parasites in host survival and reproduction, the effects of behaviour on parasitism can scale up to population-level processes, thus affecting species conservation. Understanding how conservation and infectious disease control strategies actually affect transmission potential can therefore often only be understood through a behavioural lens. We highlight how behavioural perspectives of disease ecology apply to conservation by reviewing the different ways that behavioural ecology influences parasite transmission and conservation goals. This article is part of the theme issue ‘Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation’.
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Thompson, R. C. A., e A. J. Lymbery. "Genetic variability in parasites and host—parasite interactions". Parasitology 112, S1 (marzo 1996): S7—S22. http://dx.doi.org/10.1017/s0031182000076629.
Testo completoAbstract (sommario):
SUMMARYWe have examined genetic variability in parasites in the context of ecological interactions with the host. Recent research onEchinococcus, GiardiaandCryptosporidiumhas been used to illustrate: (i) the problems that parasite variability and species recognition pose for understanding the complex and often controversial relationship between parasite and host occurrence; (ii) the need for accurate parasite characterization and the application of appropriate molecular techniques to studies on parasite transmission if fundamental questions about zoonotic relationships and risk factors are to be answered; (iii) our lack of understanding about within-host interactions between genetically heterogeneous parasites at the inter-and intraspecific levels, and the significance of such interactions with respect to evolutionary considerations and the clinical outcome of parasite infections. If advances in molecular biology and mathematical ecology are to be realized, we need to give serious consideration to the development of appropriate species concepts and in vivo systems for testing the predictions and assumptions of theoretical models.
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Holand, H., H. Jensen, T. Kvalnes, J. Tufto, H. Pärn, B.-E. Sæther e T. H. Ringsby. "Parasite prevalence increases with temperature in an avian metapopulation in northern Norway". Parasitology 146, n. 8 (12 aprile 2019): 1030–35. http://dx.doi.org/10.1017/s0031182019000337.
Testo completoAbstract (sommario):
AbstractClimate and weather conditions may have substantial effects on the ecology of both parasites and hosts in natural populations. The strength and shape of the effects of weather on parasites and hosts are likely to change as global warming affects local climate. These changes may in turn alter fundamental elements of parasite–host dynamics. We explored the influence of temperature and precipitation on parasite prevalence in a metapopulation of avian hosts in northern Norway. We also investigated if annual change in parasite prevalence was related to winter climate, as described by the North Atlantic Oscillation (NAO). We found that parasite prevalence increased with temperature within-years and decreased slightly with increasing precipitation. We also found that a mild winter (positive winter NAO index) was associated with higher mean parasite prevalence the following year. Our results indicate that both local and large scale weather conditions may affect the proportion of hosts that become infected by parasites in natural populations. Understanding the effect of climate and weather on parasite–host relationships in natural populations is vital in order to predict the full consequence of global warming.
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Walker, Josephine G., Amy Hurford, Jo Cable, Amy R. Ellison, Stephen J. Price e Clayton E. Cressler. "Host allometry influences the evolution of parasite host-generalism: theory and meta-analysis". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1719 (13 marzo 2017): 20160089. http://dx.doi.org/10.1098/rstb.2016.0089.
Testo completoAbstract (sommario):
Parasites vary widely in the diversity of hosts they infect: some parasite species are specialists—infecting just a single host species, while others are generalists, capable of infecting many. Understanding the factors that drive parasite host-generalism is of basic biological interest, but also directly relevant to predicting disease emergence in new host species, identifying parasites that are likely to have unidentified additional hosts, and assessing transmission risk. Here, we use mathematical models to investigate how variation in host body size and environmental temperature affect the evolution of parasite host-generalism. We predict that parasites are more likely to evolve a generalist strategy when hosts are large-bodied, when variation in host body size is large, and in cooler environments. We then explore these predictions using a newly updated database of over 20 000 fish–macroparasite associations. Within the database we see some evidence supporting these predictions, but also highlight mismatches between theory and data. By combining these two approaches, we establish a theoretical basis for interpreting empirical data on parasites' host specificity and identify key areas for future work that will help untangle the drivers of parasite host-generalism. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.
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Cohen, Joel E., Robert Poulin e Clément Lagrue. "Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution". Proceedings of the National Academy of Sciences 114, n. 1 (19 dicembre 2016): E47—E56. http://dx.doi.org/10.1073/pnas.1618803114.
Testo completoAbstract (sommario):
The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance–mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance–mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites.
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Werner, Courtney S., e Charles L. Nunn. "Effect of urban habitat use on parasitism in mammals: a meta-analysis". Proceedings of the Royal Society B: Biological Sciences 287, n. 1927 (13 maggio 2020): 20200397. http://dx.doi.org/10.1098/rspb.2020.0397.
Testo completoAbstract (sommario):
Rates of urbanization are increasing globally, with consequences for the dynamics of parasites and their wildlife hosts. A small subset of mammal species have the dietary and behavioural flexibility to survive in urban settings. The changes that characterize urban ecology—including landscape transformation, modified diets and shifts in community composition—can either increase or decrease susceptibility and exposure to parasites. We used a meta-analytic approach to systematically assess differences in endoparasitism between mammals in urban and non-urban habitats. Parasite prevalence estimates in matched urban and non-urban mammal populations from 33 species were compiled from 46 published studies, and an overall effect of urban habitation on parasitism was derived after controlling for study and parasite genus. Parasite life cycle type and host order were investigated as moderators of the effect sizes. We found that parasites with complex life cycles were less prevalent in urban carnivore and primate populations than in non-urban populations. However, we found no difference in urban and non-urban prevalence for parasites in rodent and marsupial hosts, or differences in prevalence for parasites with simple life cycles in any host taxa. Our findings therefore suggest the disruption of some parasite transmission cycles in the urban ecological community.
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Araujo, Adauto, Karl Reinhard, Luiz Fernando Ferreira, Elisa Pucu e Pedro Paulo Chieffi. "Paleoparasitology: the origin of human parasites". Arquivos de Neuro-Psiquiatria 71, n. 9B (settembre 2013): 722–26. http://dx.doi.org/10.1590/0004-282x20130159.
Testo completoAbstract (sommario):
Parasitism is composed by three subsystems: the parasite, the host, and the environment. There are no organisms that cannot be parasitized. The relationship between a parasite and its host species most of the time do not result in damage or disease to the host. However, in a parasitic disease the presence of a given parasite is always necessary, at least in a given moment of the infection. Some parasite species that infect humans were inherited from pre-hominids, and were shared with other phylogenetically close host species, but other parasite species were acquired from the environment as humans evolved. Human migration spread inherited parasites throughout the globe. To recover and trace the origin and evolution of infectious diseases, paleoparasitology was created. Paleoparasitology is the study of parasites in ancient material, which provided new information on the evolution, paleoepidemiology, ecology and phylogenetics of infectious diseases.
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Mohammed, Ryan S., Stanley D. King, Paul Bentzen, David Marcogliese, Cock van Oosterhout e Jackie Lighten. "Parasite diversity and ecology in a model species, the guppy ( Poecilia reticulata ) in Trinidad". Royal Society Open Science 7, n. 1 (gennaio 2020): 191112. http://dx.doi.org/10.1098/rsos.191112.
Testo completoAbstract (sommario):
The guppy ( Poecilia reticulata ) is a model species in ecology and evolution. Many studies have examined effects of predators on guppy behaviour, reproduction, survival strategies, feeding and other life-history traits, but few have studied variation in their parasite diversity. We surveyed parasites of 18 Trinidadian populations of guppy, to provide insight on the geographical mosaic of parasite variability, which may act as a source of natural selection acting on guppies. We found 21 parasite species, including five new records for Trinidad. Spatial variation in parasite diversity was significantly higher than that of piscine predators, and significant variation in parasite richness among individuals and populations was correlated with: (i) host size, (ii) snail species richness, and (iii) the distance between populations. Differences in parasite species richness are likely to play an important, yet underestimated role in the biology of this model species of vertebrate ecology and evolution.
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Springer, Andrea, e Peter M. Kappeler. "Intestinal parasite communities of six sympatric lemur species at Kirindy Forest, Madagascar". Primate Biology 3, n. 2 (7 settembre 2016): 51–63. http://dx.doi.org/10.5194/pb-3-51-2016.
Testo completoAbstract (sommario):
Abstract. Intestinal parasites impact host health, survival and reproductive success and therefore exert selective pressures on hosts' ecology and behavior. Thus, characterizing and comparing the parasitic fauna of different wildlife hosts sharing the same habitat can provide insights into the mechanisms underlying variation in parasitism, as well as the role of parasites as possible conservation threats. Several host traits have been proposed to generate differences in parasite diversity among different host species, including phylogeny, host body mass, host longevity, diet, and differences in ranging and social behavior. Here, we provide an overview of intestinal helminths and protozoa detected by fecal microscopy in six sympatric lemur species in Kirindy Forest, western Madagascar. The described patterns indicate that host phylogeny and diet may play an important role in shaping intestinal parasite assemblages in this system, as the closely related, omnivorous cheirogaleids showed the strongest overlap in parasite communities. No indication was found for an effect of body mass or longevity on parasite species richness. Regarding the effect of sociality, the two group-living lemur species, Propithecus verreauxi and Eulemur rufifrons, harbored directly transmitted parasites at higher prevalence than solitary foragers, but not at higher diversity. Effects of season and sex on parasite prevalence confirm the results of previous studies, with higher prevalence in the energetically demanding dry season and a male bias in parasitism. We highlight the opportunities of exploring the parasitic fauna of wildlife from a community ecology and evolutionary perspective, and identify prospects for future research on lemur parasitism.
24
Fong, Caitlin R., Armand M. Kuris e Ryan F. Hechinger. "Parasite and host biomass and reproductive output in barnacle populations in the rocky intertidal zone". Parasitology 146, n. 3 (10 ottobre 2018): 407–12. http://dx.doi.org/10.1017/s0031182018001634.
Testo completoAbstract (sommario):
AbstractThe rocky intertidal zone has a long history of ecological study with barnacles frequently serving as a model system to explore foundational theories. Parasites are often ignored in community ecology studies, and this particularly holds for true for the rocky intertidal zone. We explore the role of the isopod parasite, Hemioniscus balani, on its host, the acorn barnacle, Chthamalus fissus. We use the currencies of biomass and reproduction measured at the individual level, then applied to the population level, to evaluate the importance of this parasite to barnacle populations. We found H. balani can comprise substantial biomass in ‘apparent’ barnacle populations, sometimes even equaling barnacle biomass. Additionally, parasite reproduction sometimes matched barnacle reproduction. Thus, parasites divert substantial energy flow from the barnacle population and to near-shore communities in the form of parasite larvae. Parasites appeared to decrease barnacle reproduction per area. Potentially, this parasite may control barnacle populations, depending on the extent to which heavily infected barnacle populations contribute to barnacle populations at larger scales. These findings regarding the importance of a particular parasite for host population dynamics in this well studied ecosystem call for the integration of disease dynamics into community ecological studies of the rocky intertidal zone.
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Hofmeester, Tim R., Esther J. Bügel, Bob Hendrikx, Miriam Maas, Frits F. J. Franssen, Hein Sprong e Kevin D. Matson. "Parasite Load and Site-Specific Parasite Pressure as Determinants of Immune Indices in Two Sympatric Rodent Species". Animals 9, n. 12 (22 novembre 2019): 1015. http://dx.doi.org/10.3390/ani9121015.
Testo completoAbstract (sommario):
Wildlife is exposed to parasites from the environment. This parasite pressure, which differs among areas, likely shapes the immunological strategies of animals. Individuals differ in the number of parasites they encounter and host, and this parasite load also influences the immune system. The relative impact of parasite pressure vs. parasite load on different host species, particularly those implicated as important reservoirs of zoonotic pathogens, is poorly understood. We captured bank voles (Myodes glareolus) and wood mice (Apodemus sylvaticus) at four sites in the Netherlands. We sampled sub-adult males to quantify their immune function, infestation load for ecto- and gastrointestinal parasites, and infection status for vector-borne microparasites. We then used regression trees to test if variation in immune indices could be explained by among-site differences (parasite pressure), among-individual differences in infestation intensity and infection status (parasite load), or other intrinsic factors. Regression trees revealed splits among sites for haptoglobin, hemagglutination, and body-mass corrected spleen size. We also found splits based on infection/infestation for haptoglobin, hemolysis, and neutrophil to lymphocyte ratio. Furthermore, we found a split between species for hemolysis and splits based on body mass for haptoglobin, hemagglutination, hematocrit, and body-mass corrected spleen size. Our results suggest that both parasite pressure and parasite load influence the immune system of wild rodents. Additional studies linking disease ecology and ecological immunology are needed to understand better the complexities of host–parasite interactions and how these interactions shape zoonotic disease risk.
26
Stampe, Karina, Ole Næsbye Larsen e Stephanie S. Godfrey. "Ecto- and endoparasites of the King's skink (Egernia kingii) on Penguin Island". Parasitology 147, n. 10 (19 maggio 2020): 1094–99. http://dx.doi.org/10.1017/s0031182020000839.
Testo completoAbstract (sommario):
AbstractWildlife species are often host to a diversity of parasites, but our knowledge of their diversity and ecology is extremely limited, especially for reptiles. Little is known about the host-parasite ecology of the Australian lizard, the King's skink (Egernia kingii). In spring of 2015, we carried out a field-based study of a population of King's skinks on Penguin Island (Western Australia). We documented five species of parasites, including two ectoparasitic mites (an undescribed laelapid mite and Mesolaelaps australiensis), an undescribed coccidia species, and two nematode species (Pharyngodon tiliquae and Capillaria sp.). The laelapid mite was the most abundant parasite, infesting 46.9% of the 113 captured lizards. This mite species increased in prevalence and abundance over the course of the study. Infection patterns of both mites varied with lizard life-stage; sub-adults were more commonly infested with laelapid mites than adults or juveniles, and sub-adults and adults were infested by more laelapid mites than juveniles. By contrast, adults had a higher prevalence of M. australiensis than juveniles or sub-adults. Among the gastrointestinal parasites, P. tiliquae was relatively common among the sampled lizards (35.3%). These results give new important information about reptiles as parasite hosts and what factors influence infection patterns.
27
Lanfranchi, A. L., M. A. Rossin e J. T. Timi. "Parasite infracommunities of a specialized marine fish species in a compound community dominated by generalist parasites". Journal of Helminthology 83, n. 4 (22 maggio 2009): 373–78. http://dx.doi.org/10.1017/s0022149x09390069.
Testo completoAbstract (sommario):
AbstractThe structure and composition of parasite communities of Mullus argentinae were analysed under two alternative hypotheses in a sample of 75 specimens caught off Mar del Plata, Argentina (38°27′S, 57°90′W). The first, based on the dominance of trophically transmitted larval parasites of low host-specificity among fish species in the region, predicts that infracommunities will be random subsets of regionally available species. The second, based on previous studies on other mullids, predicts that infracommunities will be dominated by adult digeneans. The parasite fauna of goatfishes was mainly composed of endoparasites, with metacercariae of Prosorhynchus australis accounting for most individual parasites and greatly affecting infracommunity descriptors. Its importance was reinforced by the low number of trophically transmitted larval parasites. Both hypotheses were refuted; parasite communities were not dominated either by trophically transmitted larval parasites of low host-specificity or by adult digeneans. Prosorhynchus australis was the only species displaying any degree of phylogenetic specificity. Therefore, the influence of phylogenetic factors seems to exceed that of ecological ones in determining the observed structure of infracommunities. However, it is precisely host ecology that allows P. australis to become the determinant of infracommunity structure by constraining the acquisition of other parasites. Studies aiming to determine the relative importance of evolutionary and ecological processes as structuring forces of parasite communities should take into account not only the identity and specificity of their component parasites, but also their availability in the compound community.
28
MAIA, JOÃO P., D. JAMES HARRIS, SALVADOR CARRANZA e ELENA GOMÉZ-DÍAZ. "Assessing the diversity, host-specificity and infection patterns of apicomplexan parasites in reptiles from Oman, Arabia". Parasitology 143, n. 13 (9 settembre 2016): 1730–47. http://dx.doi.org/10.1017/s0031182016001372.
Testo completoAbstract (sommario):
SUMMARYUnderstanding the processes that shape parasite diversification, their distribution and abundance provides valuable information on the dynamics and evolution of disease. In this study, we assessed the diversity, distribution, host-specificity and infection patterns of apicomplexan parasites in amphibians and reptiles from Oman, Arabia. Using a quantitative PCR approach we detected three apicomplexan parasites (haemogregarines, lankesterellids and sarcocystids). A total of 13 haemogregarine haplotypes were identified, which fell into four main clades in a phylogenetic framework. Phylogenetic analysis of six new lankesterellid haplotypes revealed that these parasites were distinct from, but phylogenetically related to, knownLankesterellaspecies and might represent new taxa. The percentage of infected hosts (prevalence) and the number of haemogregarines in the blood (parasitaemia) varied significantly between gecko species. We also found significant differences in parasitaemia between haemogregarine parasite lineages (defined by phylogenetic clustering of haplotypes), suggesting differences in host–parasite compatibility between these lineages. ForPristurus rupestris, we found significant differences in haemogregarine prevalence between geographical areas. Our results suggest that host ecology and host relatedness may influence haemogregarine distributions and, more generally, highlight the importance of screening wild hosts from remote regions to provide new insights into parasite diversity.
29
Özer, Ahmet, e Sevilay Güneydağ. "Seasonality and host–parasite interrelationship of Mytilus galloprovincialis parasites in Turkish Black Sea coasts". Journal of the Marine Biological Association of the United Kingdom 95, n. 8 (11 giugno 2015): 1591–99. http://dx.doi.org/10.1017/s0025315415000740.
Testo completoAbstract (sommario):
This is the first comprehensive research study on the parasites of Mytilus galloprovincialis collected from the Sinop coasts of the Black Sea and their relationships with several environmental and biotic factors. A total of 1740 mussels were collected monthly at three sampling localities representing different ecosystems in the period between August 2012 and July 2013 and examined for parasites. Identified parasites were Nematopsis legeri, Peniculistoma mytili, Urastoma cyprinae, Parvatrema duboisi and Polydora ciliata. Infection prevalence (%), mean intensity and mean abundance values of each parasite species were calculated according to season, sampling localities and length classes of mussel. Nematopsis legeri was the most prevalent species (32.5%), followed by Pe. mytili (6.70%), U. cyprinae (6.30%), Pa. duboisi (4.50%) and Po. ciliata (2.20%). Nematopsis legeri and Parvatrema duboisi had their highest infection prevalence and intensity values in sampling locality III where secondary hosts present to complete their life cycle and larger sized mussels had higher parasite loads. Statistically significant differences were determined in the prevalence of infection and intensity values among seasons, length classes of mussel and sampling localities of each parasite species. The present study provided valuable information on mussel parasites and their relationships with host length, seasons and ecology.
30
Stephenson, Jessica F., Kyle A. Young, Jordan Fox, Jukka Jokela, Joanne Cable e Sarah E. Perkins. "Host heterogeneity affects both parasite transmission to and fitness on subsequent hosts". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1719 (13 marzo 2017): 20160093. http://dx.doi.org/10.1098/rstb.2016.0093.
Testo completoAbstract (sommario):
Infectious disease dynamics depend on the speed, number and fitness of parasites transmitting from infected hosts (‘donors’) to parasite-naive ‘recipients’. Donor heterogeneity likely affects these three parameters, and may arise from variation between donors in traits including: (i) infection load, (ii) resistance, (iii) stage of infection, and (iv) previous experience of transmission. We used the Trinidadian guppy, Poecilia reticulata , and a directly transmitted monogenean ectoparasite, Gyrodactylus turnbulli , to experimentally explore how these sources of donor heterogeneity affect the three transmission parameters. We exposed parasite-naive recipients to donors (infected with a single parasite strain) differing in their infection traits, and found that donor infection traits had diverse and sometimes interactive effects on transmission. First, although transmission speed increased with donor infection load, the relationship was nonlinear. Second, while the number of parasites transmitted generally increased with donor infection load, more resistant donors transmitted more parasites, as did those with previous transmission experience. Finally, parasites transmitting from experienced donors exhibited lower population growth rates on recipients than those from inexperienced donors. Stage of infection had little effect on transmission parameters. These results suggest that a more holistic consideration of within-host processes will improve our understanding of between-host transmission and hence disease dynamics. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.
31
YOUNG, REBECCA E., e ANDREW D. C. MACCOLL. "Spatial and temporal variation in macroparasite communities of three-spined stickleback". Parasitology 144, n. 4 (20 ottobre 2016): 436–49. http://dx.doi.org/10.1017/s0031182016001815.
Testo completoAbstract (sommario):
SummaryPatterns in parasite community structure are often observed in natural systems and an important question in parasite ecology is whether such patterns are repeatable across time and space. Field studies commonly look at spatial or temporal repeatability of patterns, but they are rarely investigated in conjunction. We use a large dataset on the macroparasites of the three-spined stickleback,Gasterosteus aculeatusL., collected from 14 locations on North Uist, Scotland over an 8-year period to investigate: (1) repeatability of patterns in parasite communities among populations and whether variation is consistent across years, (2) whether variation between years can be explained by climatic variation and progression of the season and (3) whether variation in habitat characteristics explain population differences. Differences in relative abundance and prevalence across populations were observed in a number of parasites investigated indicating a lack of consistency across years in numerous parasite community measures; however, differences between populations in the prevalence and abundance of some parasites were consistent throughout the study. Average temperature did not affect parasite community, and progression of the season was only significant for two of 13 community measures. Two of the six habitat characteristics investigated (pH and calcium concentration) significantly affected parasite presence.
32
Shapiro, Lillian L. M., Courtney C. Murdock, Gregory R. Jacobs, Rachel J. Thomas e Matthew B. Thomas. "Larval food quantity affects the capacity of adult mosquitoes to transmit human malaria". Proceedings of the Royal Society B: Biological Sciences 283, n. 1834 (13 luglio 2016): 20160298. http://dx.doi.org/10.1098/rspb.2016.0298.
Testo completoAbstract (sommario):
Adult traits of holometabolous insects are shaped by conditions experienced during larval development, which might impact interactions between adult insect hosts and parasites. However, the ecology of larval insects that vector disease remains poorly understood. Here, we used Anopheles stephensi mosquitoes and the human malaria parasite Plasmodium falciparum, to investigate whether larval conditions affect the capacity of adult mosquitoes to transmit malaria. We reared larvae in two groups; one group received a standard laboratory rearing diet, whereas the other received a reduced diet. Emerging adult females were then provided an infectious blood meal. We assessed mosquito longevity, parasite development rate and prevalence of infectious mosquitoes over time. Reduced larval food led to increased adult mortality and caused a delay in parasite development and a slowing in the rate at which parasites invaded the mosquito salivary glands, extending the time it took for mosquitoes to become infectious. Together, these effects increased transmission potential of mosquitoes in the high food regime by 260–330%. Such effects have not, to our knowledge, been shown previously for human malaria and highlight the importance of improving knowledge of larval ecology to better understand vector-borne disease transmission dynamics.
33
Forbes, Mark R., André Morrill e Jennifer Schellinck. "Host species exploitation and discrimination by animal parasites". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1719 (13 marzo 2017): 20160090. http://dx.doi.org/10.1098/rstb.2016.0090.
Testo completoAbstract (sommario):
Parasite species often show differential fitness on different host species. We developed an equation-based model to explore conditions favouring host species exploitation and discrimination. In our model, diploid infective stages randomly encountered hosts of two species; the parasite's relative fitness in exploiting each host species, and its ability to discriminate between them, was determined by the parasite's genotype at two independent diallelic loci. Relative host species frequency determined allele frequencies at the exploitation locus, whereas differential fitness and combined host density determined frequency of discrimination alleles. The model predicts instances where populations contain mixes of discriminatory and non-discriminatory infective stages. Also, non-discriminatory parasites should evolve when differential fitness is low to moderate and when combined host densities are low, but not so low as to cause parasite extinction. A corollary is that parasite discrimination (and host-specificity) increases with higher combined host densities. Instances in nature where parasites fail to discriminate when differential fitness is extreme could be explained by one host species evolving resistance, following from earlier selection for parasite non-discrimination. Similar results overall were obtained for haploid extensions of the model. Our model emulates multi-host associations and has implications for understanding broadening of host species ranges by parasites. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.
34
Hernandez-Caballero, Irene, Luz Garcia-Longoria, Ivan Gomez-Mestre e Alfonso Marzal. "The Adaptive Host Manipulation Hypothesis: Parasites Modify the Behaviour, Morphology, and Physiology of Amphibians". Diversity 14, n. 9 (8 settembre 2022): 739. http://dx.doi.org/10.3390/d14090739.
Testo completoAbstract (sommario):
Parasites have evolved different strategies to increase their transmission from one host to another. The Adaptive Host Manipulation hypothesis states that parasites induce modifications of host phenotypes that could maximise parasite fitness. There are numerous examples of parasite manipulation across a wide range of host and parasite taxa. However, the number of studies exploring the manipulative effects of parasites on amphibians is still scarce. Herein, we extensively review the current knowledge on phenotypic alterations in amphibians following parasite infection. Outcomes from different studies show that parasites may manipulate amphibian behaviours to favour their transmission among conspecifics or to enhance the predation of infected amphibians by a suitable definite host. In addition, parasites also modify the limb morphology and impair locomotor activity of infected toads, frogs, and salamanders, hence facilitating their ingestion by a final host and completing the parasite life cycle. Additionally, parasites may alter host physiology to enhance pathogen proliferation, survival, and transmission. We examined the intrinsic (hosts traits) and extrinsic (natural and anthropogenic events) factors that may determine the outcome of infection, where human-induced changes of environmental conditions are the most harmful stressors that enhance amphibian exposure and susceptibility to parasites.
35
TURNER, A. K., P. M. BELDOMENICO, K. BOWN, S. J. BURTHE, J. A. JACKSON, X. LAMBIN e M. BEGON. "Host–parasite biology in the real world: the field voles of Kielder". Parasitology 141, n. 8 (10 marzo 2014): 997–1017. http://dx.doi.org/10.1017/s0031182014000171.
Testo completoAbstract (sommario):
SUMMARYResearch on the interactions between the field voles (Microtus agrestis) of Kielder Forest and their natural parasites dates back to the 1930s. These early studies were primarily concerned with understanding how parasites shape the characteristic cyclic population dynamics of their hosts. However, since the early 2000s, research on the Kielder field voles has expanded considerably and the system has now been utilized for the study of host–parasite biology across many levels, including genetics, evolutionary ecology, immunology and epidemiology. The Kielder field voles therefore represent one of the most intensely and broadly studied natural host–parasite systems, bridging theoretical and empirical approaches to better understand the biology of infectious disease in the real world. This article synthesizes the body of work published on this system and summarizes some important insights and general messages provided by the integrated and multidisciplinary study of host–parasite interactions in the natural environment.
36
Veiga, Jesús, Eulalia Moreno, Jesús Benzal e Francisco Valera. "Off-host longevity of the winged dispersal stage ofCarnus hemapterus(Insecta: Diptera) modulated by gender, body size and food provisioning". Parasitology 146, n. 2 (8 agosto 2018): 241–45. http://dx.doi.org/10.1017/s0031182018001300.
Testo completoAbstract (sommario):
AbstractHighlighting the dispersal ecology of parasites is important for understanding epidemiological, demographic and coevolutionary aspects of host–parasite interactions. Yet, critical aspects of the dispersal stage of parasites, such as longevity and the factors influencing it, are poorly known. Here we study the lifespan of the dispersal stage of an ectoparasitic dipteran,Carnus hemapterus, and the impact of gender, body size and food provisioning on longevity. We found that freshly emerged imagoes survive at most less than 4 days. Longevity increased with body size and, since this parasite exhibits sexual size dimorphism, the bigger females lived longer than males. However, controlling for body size suggests that males lived relatively longer than females. Furthermore, a humid environment and food provisioning (flowers) significantly increased individual life spans. We discuss the relative importance of spatial and temporal dispersal in relation to the infectious potential of this parasite.
37
POULIN, R. "Relative infection levels and taxonomic distances among the host species used by a parasite: insights into parasite specialization". Parasitology 130, n. 1 (13 dicembre 2004): 109–15. http://dx.doi.org/10.1017/s0031182004006304.
Testo completoAbstract (sommario):
Parasites often exploit more than one host species at any stage in their life-cycle, but the extent to which these host species are used varies greatly. Parasites typically achieve their highest prevalence, intensity and/or abundance in one host species (the principal host), whereas infection levels in auxiliary hosts range from relatively high to very low. The present study examines what influences the distribution of parasite individuals among their different host species, using metazoan parasites that use freshwater fish as their definitive or only host. Specifically, I test the hypothesis that differences in relative infection levels by a parasite among its auxiliary hosts are proportional to the taxonomic distance between the respective auxiliary hosts and the parasite's principal host. Taxonomic distance among hosts is a surrogate measure of their similarity in terms of ecology, physiology and immunology. Using data on 29 parasite species and 6 fish communities, for a total of 47 parasite-locality combinations, it was found that taxonomic distance between the auxiliary hosts and the principal host had no real influence on infection levels in auxiliary hosts, measured as either prevalence, intensity or abundance. The analysis revealed differences in the degree of specialization among major groups of parasites: in terms of abundance or intensity, auxiliary hosts were less important for cestodes than for nematodes and copepods. The lack of an effect of taxonomic distance may indicate that ecological similarity among host species, arising from convergence and not from relatedness, is more important than host phylogeny or taxonomy. Although the results are based on a limited number of parasite taxa, they suggest that parasites may be opportunistic in their colonization of new hosts, and not severely constrained by evolutionary baggage.
38
Paterson, Rachel A., Gustavo P. Viozzi, Carlos A. Rauque, Verónica R. Flores e Robert Poulin. "A Global Assessment of Parasite Diversity in Galaxiid Fishes". Diversity 13, n. 1 (14 gennaio 2021): 27. http://dx.doi.org/10.3390/d13010027.
Testo completoAbstract (sommario):
Free-living species often receive greater conservation attention than the parasites they support, with parasite conservation often being hindered by a lack of parasite biodiversity knowledge. This study aimed to determine the current state of knowledge regarding parasites of the Southern Hemisphere freshwater fish family Galaxiidae, in order to identify knowledge gaps to focus future research attention. Specifically, we assessed how galaxiid–parasite knowledge differs among geographic regions in relation to research effort (i.e., number of studies or fish individuals examined, extent of tissue examination, taxonomic resolution), in addition to ecological traits known to influence parasite richness. To date, ~50% of galaxiid species have been examined for parasites, though the majority of studies have focused on single parasite taxa rather than assessing the full diversity of macro- and microparasites. The highest number of parasites were observed from Argentinean galaxiids, and studies in all geographic regions were biased towards the highly abundant and most widely distributed galaxiid species, Galaxias maculatus. Parasite diversity generally increased with the number of studies and individual fish examined, however studies which examined parasites from all body tissues could overcome the effects of low study effort. In order to promote further understanding of galaxiid–parasite biodiversity, we provide a series of recommendations, including the use of molecular techniques to verify parasite identity, and highlight the future roles both fish biologists and parasitologists can play.
39
Hicks, Olivia, Sarah J. Burthe, Francis Daunt, Mark Newell, Adam Butler, Motohiro Ito, Katsufumi Sato e Jonathan A. Green. "The energetic cost of parasitism in a wild population". Proceedings of the Royal Society B: Biological Sciences 285, n. 1879 (30 maggio 2018): 20180489. http://dx.doi.org/10.1098/rspb.2018.0489.
Testo completoAbstract (sommario):
Parasites have profound fitness effects on their hosts, yet these are often sub-lethal, making them difficult to understand and quantify. A principal sub-lethal mechanism that reduces fitness is parasite-induced increase in energetic costs of specific behaviours, potentially resulting in changes to time and energy budgets. However, quantifying the influence of parasites on these costs has not been undertaken in free-living animals. We used accelerometers to estimate energy expenditure on flying, diving and resting, in relation to a natural gradient of endo-parasite loads in a wild population of European shags Phalacrocorax aristotelis . We found that flight costs were 10% higher in adult females with higher parasite loads and these individuals spent 44% less time flying than females with lower parasite loads. There was no evidence for an effect of parasite load on daily energy expenditure, suggesting the existence of an energy ceiling, with the increase in cost of flight compensated for by a reduction in flight duration. These behaviour specific costs of parasitism will have knock-on effects on reproductive success, if constraints on foraging behaviour detrimentally affect provisioning of young. The findings emphasize the importance of natural parasite loads in shaping the ecology and life-history of their hosts, which can have significant population level consequences.
40
Sobecka, Ewa, Ewa Łuczak, Beata Więcaszek e Artur Antoszek. "Parasite community structure of cod from Bear Island (Barents Sea) and Pomeranian Bay (Baltic Sea)". Polish Polar Research 32, n. 3 (1 gennaio 2011): 253–62. http://dx.doi.org/10.2478/v10183-011-0016-6.
Testo completoAbstract (sommario):
Parasite community structure of cod from Bear Island (Barents Sea) and Pomeranian Bay (Baltic Sea) A total of 142 cods: 60 from the South-East Ground of Bear Island and 82 from the Pomeranian Bay (Baltic Sea) were examined for their ecto- and endoparasites. Twenty different parasite species, comprising one Myxosporea, three Cestoda, four Digenea, seven Nematoda, three Acanthocephala and two Crustacea were found. The parasite component communities comprised 1446 individuals (17 species, six higher taxa) from the Bear Island and 6588 individuals (nine species, three higher taxa) from Pomeranian Bay. The observed parasite host specificity was low, and the intensity in a single fish ranged from one to 279 specimens. The eudominant parasite species were Echinorhynchus gadi, Hemiurus levinseni and Contracaecum osculatum. The dominant parasite communities from the Bear Island were nematodes, but acanthocephalans dominated in cod from the Baltic Sea. It appears that one group of parasites, better adapted for the specific conditions of the macrohabitat, has replaced another. The most prevalent parasites were E. gadi, Anisakis simplex, C. osculatum and Hysterothylacium aduncum, and the mean values of crowding were the highest for E. gadi and Pomphorhynchus laevis. The nematode Camallanus lacustris was noted in this host species for the first time. Only six species of parasites were common to cod from both fishing grounds.
41
Damas-Moreira, Isabel, João P. Maia, Beatriz Tomé, Daniele Salvi, Ana Perera e D. James Harris. "Blood parasites in sympatric lizards: what is their impact on hosts’ immune system?" Amphibia-Reptilia 43, n. 1 (5 gennaio 2022): 37–49. http://dx.doi.org/10.1163/15685381-bja10078.
Testo completoAbstract (sommario):
Abstract Assessment of parasites and their pathogenicity is essential for studying the ecology of populations and understanding their dynamics. In this study, we investigate the prevalence and intensity of infection of haemogregarines (phylum Apicomplexa) in two sympatric lizard species, Podarcis vaucheri and Scelarcis perspicillata, across three localities in Morocco, and their effect on host immune response. We used the Phytohaemagglutinin (PHA) skin testing technique to relate the level of immune response with parasite infection. Prevalence and intensity levels were estimated with microscopy, and 18S rRNA gene sequences were used to confirm parasite identity. All parasites belong to the haemogregarine lineage found in other North African reptiles. There were differences in prevalence between localities and sexes. Overall, infected lizards were larger than uninfected ones, although we did not detect differences in parasitaemia across species, sex or locality. The swelling response was not related to the presence or number of haemogregarines, or to host body size, body condition, sex or species. We found no evidence of impact for these parasites on the circulating blood cells or the hosts’ immune system, but more data is needed to assess the potential impact of mixed infections, and the possibility of cryptic parasite species.
42
Quigley, Benjamin J. Z., Sam P. Brown, Helen C. Leggett, Pauline D. Scanlan e Angus Buckling. "Within-host interference competition can prevent invasion of rare parasites". Parasitology 145, n. 6 (15 maggio 2017): 770–74. http://dx.doi.org/10.1017/s003118201700052x.
Testo completoAbstract (sommario):
AbstractCompetition between parasite species or genotypes can play an important role in the establishment of parasites in new host populations. Here, we investigate a mechanism by which a rare parasite is unable to establish itself in a host population if a common resident parasite is already present (a ‘priority effect’). We develop a simple epidemiological model and show that a rare parasite genotype is unable to invade if coinfecting parasite genotypes inhibit each other's transmission more than expected from simple resource partitioning. This is because a rare parasite is more likely to be in multiply-infected hosts than the common genotype, and hence more likely to pay the cost of reduced transmission. Experiments competing interfering clones of bacteriophage infecting a bacterium support the model prediction that the clones are unable to invade each other from rare. We briefly discuss the implications of these results for host-parasite ecology and (co)evolution.
43
Suhonen, Jukka, Jaakko J. Ilvonen, Tommi Nyman e Jouni Sorvari. "Brood parasitism in eusocial insects (Hymenoptera): role of host geographical range size and phylogeny". Philosophical Transactions of the Royal Society B: Biological Sciences 374, n. 1769 (11 febbraio 2019): 20180203. http://dx.doi.org/10.1098/rstb.2018.0203.
Testo completoAbstract (sommario):
Interspecific brood parasitism is common in many animal systems. Brood parasites enter the nests of other species and divert host resources for producing their own offspring, which can lead to strong antagonistic parasite–host coevolution. Here, we look at commonalities among social insect species that are victims of brood parasites, and use phylogenetic data and information on geographical range size to predict which species are most probably to fall victims to brood parasites in the future. In our analyses, we focus on three eusocial hymenopteran groups and their brood parasites: (i) bumblebees, (ii) Myrmica ants, and (iii) vespine and polistine wasps. In these groups, some, but not all, species are parasitized by obligate workerless inquilines that only produce reproductive-caste descendants. We find phylogenetic signals for geographical range size and the presence of parasites in bumblebees, but not in ants and wasps. Phylogenetic logistic regressions indicate that the probability of being attacked by one or more brood parasite species increases with the size of the geographical range in bumblebees, but the effect is statistically only marginally significant in ants. However, non-phylogenetic logistic regressions suggest that bumblebee species with the largest geographical range sizes may have a lower likelihood of harbouring social parasites than do hosts with medium-sized ranges. Our results provide new insights into the ecology and evolution of host–social parasite systems, and indicate that host phylogeny and geographical range size can be used to predict threats posed by social parasites, as well to design efficient conservation measures for both hosts and their parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.
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Weatherhead, Patrick J., e Gordon F. Bennett. "Ecology of Red-winged Blackbird parasitism by haematozoa". Canadian Journal of Zoology 69, n. 9 (1 settembre 1991): 2352–59. http://dx.doi.org/10.1139/z91-331.
Testo completoAbstract (sommario):
We sampled haematozoa in Red-winged Blackbirds (Agelaius phoeniceus) over three consecutive breeding seasons in eastern Ontario to identify factors that affect the reliability of quantifying parasites as this pertains to testing Hamilton and Zuk's hypothesis of sexual selection. Parasite prevalence and intensity varied seasonally, indicating that for samples to be reliable they should not be taken either early or late in the breeding season, and analysis should be limited to prevalence (presence versus absence). Among males (but not females), parasite prevalence increased with age, indicating that all individuals are not exposed to parasites early in life, and therefore tests of the "parasite" hypothesis of sexual selection are best restricted to older individuals. Resampling of known individuals within and between years showed that some individuals changed from positive to negative. Prevalence estimates also varied by year, indicating that reliable estimates of prevalence for a species, necessary for interspecific tests of the parasite hypothesis, will require extensive sampling. Overall, parasite prevalence did not vary with habitat. Parasites were detectable in only 1 of 119 nestlings sampled, indicating either lack of exposure or inadequate time for infections to reach detectable intensities. In either case, it is not possible to test the assumption that parasite resistance is heritable using blood samples from nestlings. Although males and females were parasitized by the same array of parasites, the distribution of specific parasites differed significantly (males were more heavily parasitized by leucocytozoids). If males and females generally differ in either exposure or resistance to specific parasites, the coevolutionary dynamics between host and parasite and the implications for sexual selection will require reassessment.
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Sukhdeo, M. V. K., e S. C. Sukhdeo. "Optimal habitat selection by helminths within the host environment". Parasitology 109, S1 (1994): S41—S55. http://dx.doi.org/10.1017/s0031182000085073.
Testo completoAbstract (sommario):
SUMMARYHelminth parasites of vertebrates usually select very specific regions or habitats in their hosts, and this is often preceded by a tortuous migration through various host organs. However, the proximate mechanisms of migration and habitat selection have remained enigmatic despite considerable effort by parasitologists. In this paper, a new approach to studying helminth behaviour in the host is proposed. The core idea is that behaviour strategies must be considered from the perspective of the parasites and their perceptions of their environment. A guiding principle is that the environmental features to which an animal responds, and the actions which are required for responding to the environment, form a fundamental unit of behaviour. Thus, we can deduce an animal's behavioural strategy from the details of its response to environmental signals and from its sensory capabilities. The evidence presented suggests that helminth behaviours in the host often occur as fixed (or modal) action patterns which are usually seen in response to constant, or predictable environmental features. Thus, a working hypothesis is that the mechanisms of physiological and biochemical homeostasis within the host provide an extremely predictable environment for the parasite. Under these conditions, a parasite needs to perceive only small subsets of the total information available from the environment to respond appropriately. Studies on sensory and nervous systems of these organisms are critical to understanding parasite perception, but there are formidable technical obstacles that prevent easy access to parasite nervous systems. Therefore, a multidisciplinary approach, using ideas from parasitology, ecology, evolutionary biology and neuroethology, is considered requisite for reconstructing the parasites' behaviour strategies. It is suggested that future directions should pursue integration of studies on sensory physiology with the behavioural ecology of these organisms.
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Leggett, Helen C., Geoff Wild, Stuart A. West e Angus Buckling. "Fast-killing parasites can be favoured in spatially structured populations". Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1719 (13 marzo 2017): 20160096. http://dx.doi.org/10.1098/rstb.2016.0096.
Testo completoAbstract (sommario):
It is becoming increasingly clear that the evolution of infectious disease is influenced by host population structure. Theory predicts that parasites should be more ‘prudent’—less transmissible—in spatially structured host populations. However, here we (i) highlight how low transmission, the phenotype being selected for in this in context, may also be achieved by rapacious host exploitation, if fast host exploitation confers a local, within-host competitive advantage and (ii) test this novel concept in a bacteria–virus system. We found that limited host availability and, to a lesser extent, low relatedness favour faster-killing parasites with reduced transmission. By contrast, high host availability and high relatedness favour slower-killing, more transmissible parasites. Our results suggest high, rather than low, virulence may be selected in spatially structured host–parasite communities where local competition and hence selection for a within-host fitness advantage is high. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’.
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Wolinska, Justyna, Sabine Giessler e Henrike Koerner. "Molecular Identification and Hidden Diversity of Novel Daphnia Parasites from European Lakes". Applied and Environmental Microbiology 75, n. 22 (18 settembre 2009): 7051–59. http://dx.doi.org/10.1128/aem.01306-09.
Testo completoAbstract (sommario):
ABSTRACT Parasites play important roles in local population dynamics and genetic structure. However, due to insufficient diagnostic tools, detailed host-parasite interactions may remain concealed by hidden parasite diversity in natural systems. Microscopic examination of 19 European lake Daphnia populations revealed the presence of three groups of parasites: fungi, microsporidia, and oomycetes. For most of these parasites no genetic markers have been described so far. Based on sequence similarities of the nuclear small-subunit and internal transcribed spacer (ITS) rRNA gene regions, one fungus, four microsporidian, and nine oomycete taxa were discovered in 147 infected Daphnia (and/or three other zooplankton crustaceans). Additionally, cloning of rRNA gene regions revealed parasite sequence variation within host individuals. This was most pronounced in the ITS region of one microsporidian taxon, where the within-host sequence variation ranged from 1.7% to 5.3% polymorphic sites for parasite isolates from 14 different geographical locations. Interestingly, the parasite isolates from close locations grouped together based on sequence similarities, suggesting that there was parasite dispersal. Taken together, the data obtained in this study revealed hidden diversity of parasite communities in Daphnia lake populations. Moreover, a higher level of resolution for identifying parasite strains makes it possible to test new hypotheses with respect to parasite dispersal, transmission routes, and coinfection.
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Duffy, Meghan A., Timothy Y. James e Alan Longworth. "Ecology, Virulence, and Phylogeny of Blastulidium paedophthorum, a Widespread Brood Parasite of Daphnia spp." Applied and Environmental Microbiology 81, n. 16 (5 giugno 2015): 5486–96. http://dx.doi.org/10.1128/aem.01369-15.
Testo completoAbstract (sommario):
ABSTRACTParasitism is now recognized as a major factor impacting the ecology and evolution of plankton, includingDaphnia. Parasites that attack the developing embryos of daphniids, known as brood parasites, were first described in the early 1900s but have received relatively little study. Here, we link previous morphological descriptions of the oomycete brood parasiteBlastulidium paedophthorumwith information on its phylogenetic placement, ecology, and virulence. Based on the morphology and phylogenetic relationship with other members of theLeptomitales, we show that a brood parasite observed in daphniids in the Midwestern United States isB. paedophthorum. We used morphology, DNA sequences, and laboratory infection experiments to show thatB. paedophthorumis a multihost parasite that can be transmitted between species and genera. A field survey of six hosts in 15 lakes revealed thatB. paedophthorumis common in all six host taxa (present on 38.3% of our host species-lake-sampling date combinations; the maximum infection prevalences were 8.7% of the population and 20% of the asexual adult female population). AlthoughB. paedophthorumwas observed in all 15 lakes, presence and infection prevalence varied among lakes. Infection withB. paedophthorumdid not reduce host life span but significantly impacted host fecundity. Theory predicts that parasites that affect host fecundity without affecting host life span should have the strongest impact on host population dynamics. Based on its virulence and commonness in natural populations and on the central role of daphniids in freshwater food webs, we predict thatB. paedophthorumwill influence daphniid ecology and evolution, as well as the larger food web.
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Robar, Nicholas, Dennis L. Murray e Gary Burness. "Effects of parasites on host energy expenditure: the resting metabolic rate stalemate". Canadian Journal of Zoology 89, n. 11 (novembre 2011): 1146–55. http://dx.doi.org/10.1139/z11-084.
Testo completoAbstract (sommario):
Detrimental effects of parasitism on host fitness are frequently attributed to parasite-associated perturbations to host energy budgets. It has therefore been widely hypothesized that energetic costs of infection may be manifest as changes in host resting metabolic rate (RMR). Attempts to quantify these effects have yielded contradictory results across host–parasite systems. We used a meta-analysis of the literature to test the effects of parasites on mass-specific (n = 22) and whole-body (n = 15) host RMR. Parasites resulted in a qualitative increase in host RMR in the majority of studies; however, the overall effect of parasites on host RMR was small and statistically nonsignificant. Additionally, substantial among-study variation in host RMR could not be explained by any of the tested covariates. We conclude that the lack of an overall effect of parasites on host metabolism reflects inconsistent directionality and varying magnitudes of parasite-associated effects across studies, rather than an absence of system-specific effects. We contend that a general understanding of parasite effects on host energetics may be best achieved through identifying mechanisms underlying among-system variance in parasite effects on host RMR and relating parasite-associated perturbations of host energy budgets to robust estimates of host fitness.
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Vermeulen, Elke T., Michelle L. Power, David A. Nipperess, Ian Beveridge e Mark D. B. Eldridge. "Biodiversity of parasite assemblages in the genus Petrogale and its relation to the phylogeny and biogeography of their hosts". Australian Journal of Zoology 64, n. 1 (2016): 61. http://dx.doi.org/10.1071/zo16023.
Testo completoAbstract (sommario):
Parasites form an integral part of overall biodiversity although they are often overlooked in conservation management, where emphasis is primarily directed towards the host. Parasites are often highly specialised to particular hosts, and thus may be just as threatened as the host they inhabit. For many of Australia’s wildlife species, little is known about their associated parasite communities. To begin to address this knowledge gap, we documented the parasite fauna described in the genetically diverse marsupial genus Petrogale, which contains seven species of conservation concern. The literature evaluation showed parasites of Petrogale to be highly diverse, with 17 species of protozoa, 8 species of cestodes, 102 species of nematodes and 30 species of ectoparasites identified in 16 of 17 Petrogale host species. A comparison of the parasite communities amongst Petrogale host species indicated a highly significant correlation between the parasite community similarity, and the phylogeny (P = 0.008) and biogeography (P = 0.0001) of their Petrogale hosts, suggesting high host specificity within their associated parasite assemblages. Five Petrogale species have established species recovery programs and their parasite communities should also be considered threatened, and management of parasite diversity required as part of these conservation programs.