Segui questo link per vedere altri tipi di pubblicazioni sul tema: Leptospira.
Articoli di riviste sul tema "Leptospira"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Leptospira".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Masuzawa, Toshiyuki, Yuji Hashiguchi, Ryuta Nakamura, Ryoma Suzuki, Tadayori Shimizu, Yoshihisa Iwamoto, Tamotsu Morita e Yasutake Yanagihara. "Experimental lethal infection of Leptospira interrogans in mice treated with cyclophosphamide". Canadian Journal of Microbiology 37, n. 4 (1 aprile 1991): 312–15. http://dx.doi.org/10.1139/m91-048.
Testo completoAbstract (sommario):
After preadministration of cyclophosphamide (300 mg/kg), BALB/c mice were lethally infected with Leptospira interrogans serovar lai and a virulent strain of Leptospira interrogans serovar copenhageni, and leptospiral cells were detected in both kidneys of infected mice by indirect immunofluorescent assay. Nonpathogenic leptospirae, Leptospira biflexa serovar patoc, Leptonema illini, and an avirulent strain of L. interrogans serovar copenhageni, were not parasitic to the mice treated with cyclophosphamide. The cyclophosphamide-treated mice were protected from the homologous leptospiral infection by passive immunization with anti-leptospiral monoclonal antibody or with rabbit antiserum and by active immunization with lyophilized organisms or with protective antigen. The results of active immunization in mice treated with cyclophosphamide agreed well with those in nontreated hamsters, which were sensitive to the organisms. Furthermore, these experiments were reproducible with any lot of cyclophosphamide used. These results indicated that cyclophosphamide-treated mice can be used in the experimental infection of Leptospira in place of hamsters or guinea pigs. Key words: Leptospira interrogans, protective antigen, mice, cyclophosphamide, immunosuppression.
2
Zhao, Wei, Chun-Yan Chen, Xiang-Yan Zhang, Wei-Qiang Lai, Bao-Yu Hu, Guo-Ping Zhao, Jin-Hong Qin e Xiao-Kui Guo. "Molecular characterization of the pL40 protein inLeptospira interrogans". Canadian Journal of Microbiology 55, n. 6 (giugno 2009): 739–49. http://dx.doi.org/10.1139/w09-014.
Testo completoAbstract (sommario):
Leptospirosis is a widespread zoonotic disease caused by pathogenic leptospires. The identification of outer membrane proteins (OMPs) conserved among pathogenic leptospires, which are exposed on the leptospiral surface and expressed during mammalian infection, has become a major focus of leptospirosis research. pL40, a 40 kDa protein coded by the LA3744 gene in Leptospira interrogans , was found to be unique to Leptospira . Triton X-114 fractionation and flow cytometry analyses indicate that pL40 is a component of the leptospiral outer membrane. The conservation of pL40 among Leptospira strains prevalent in China was confirmed by both Western blotting and PCR screening. Furthermore, the pL40 antigen could be recognized by sera from guinea pigs and mice infected with low-passage L. interrogans. These findings indicate that pL40 may serve as a useful serodiagnostic antigen and vaccine candidate for L. interrogans.
3
LI, S. J., D. M. WANG, C. C. ZHANG, X. W. LI, H. M. YANG, K. C. TIAN, X. Y. WEI et al. "Molecular typing of Leptospira spp. strains isolated from field mice confirms a link to human leptospirosis". Epidemiology and Infection 141, n. 11 (13 febbraio 2013): 2278–85. http://dx.doi.org/10.1017/s0950268813000216.
Testo completoAbstract (sommario):
SUMMARYIn recent years, human leptospirosis has been reported in Jinping and Liping counties, Guizhou province, but the leptospires have never been isolated. To track the source of infection and understand the aetiological characteristics, we performed surveillance for field mice carriage of leptospirosis in 2011. Four strains of leptospire were isolated from Apodemus agrarius. PCR confirmed the four isolates as pathogenic. Multiple-locus variable-number tandem repeat analysis (MLVA) showed that the four strains were closely related to serovar Lai strain 56601 belonging to serogroup Icterohaemorrhagiae, which is consistent with the antibody detection results from local patients. Furthermore, the diversity of leptospiral isolates from different hosts and regions was demonstrated with MLVA. Our results suggest that A. agrarius may be the main carrier of Leptospira in Jinping and Liping counties, and the serogroup Icterohaemorrhagiae serovar may be the epidemic serogroup of Leptospira. This will contribute to the control and prevention of leptospirosis in these localities.
4
Doungchawee, Galayanee, Worachart Sirawaraporn, Albert Icksang-Ko, Suraphol Kongtim, Pimjai Naigowit e Visith Thongboonkerd. "Use of immunoblotting as an alternative method for serogrouping Leptospira". Journal of Medical Microbiology 56, n. 5 (1 maggio 2007): 587–92. http://dx.doi.org/10.1099/jmm.0.47143-0.
Testo completoAbstract (sommario):
Leptospirosis is a worldwide zoonotic disease caused by a spirochaete bacterium, Leptospira. Serological detection of this micro-organism basically relies on a conventional microscopic agglutination test (MAT), which has some limitations and disadvantages. In the present study, immunoblotting has been applied as an alternative method for differentiating serogroups and serovars of leptospires. Leptospiral whole-cell lysates from a total of 26 serovars were subjected to immunoblotting using rabbit antisera against individual serovars. The findings clearly demonstrated that the pattern of immunoreactive bands could be used to differentiate between leptospires of different serogroups, consistent with MAT results. There was a multi-band pattern that was unique for the pathogenic Leptospira antigens and was not observed in the non-pathogenic Leptospira biflexa and non-leptospiral bacteria (i.e. Escherichia coli, Burkholderia pseudomallei and Helicobacter pylori). For pathogenic Leptospira species, a prominent smear-like band at approximately 19–30 kDa was present when the antigens were probed with the homologous antisera. The molecular size of the prominent band, although it showed a cross-reaction between members within the same serogroup, differed among different serovars. The results obtained from polyclonal antibodies (antisera) were confirmed using mAb. With its simplicity and safety of experimental procedures, it is proposed that immunoblotting may potentially be useful as an alternative method for differentiating between serogroups of leptospires.
5
Piredda, Ivana, Loris Bertoldi, Giuseppe Benvenuto, Bruna Palmas, Aureliana Pedditzi, Pierangela Pintore e Valentina Chisu. "First Isolation and Molecular Typing of Pathogenic and Intermediate Leptospira Species from Urine of Symptomatic Dogs". Veterinary Sciences 8, n. 12 (2 dicembre 2021): 304. http://dx.doi.org/10.3390/vetsci8120304.
Testo completoAbstract (sommario):
Aim of this study was to evaluate, the presence and diversity of Leptospira spp. in blood and urine samples collected from 175 owned-dogs from Sardinia, Italy. After determination of leptospiral infection by microscopic agglutination test (MAT), urine from MAT-positive dogs were examined by real-time polymerase chain reaction (lipL32 rt-PCR) and then isolated by culture. In order to characterize obtained serovars, positive cultures were then subjected to 16S rRNA and secY sequencing, phylogenetic analysis and Multilocus Sequence Typing (MLST). Results showed that seven dogs (4%; 95% CI: 0–55) had Leptospira DNAs in their urine and five strains were isolated from urine cultures. The three different sequence types (ST17, ST198 and ST24) belonging to Leptospira interrogans genomospecies identified by MLST analyses in this study, confirmed that the leptospiral infection was widespread in Sardinian dogs. We also reported the first characterization of a new Leptospira spp. isolated from urine of one dog living in the study area. Whole genome sequencing and phylogenetic analysis, confirmed that this genospecies was closely related to Leptospira hovindhougenii, an intermediate Leptospira spp. with unknown pathogenicity previously isolated from a rat in Denmark. Further studies are required to clarify whether healthy dogs that shed leptospires in their urine could represent a zoonotic risk for humans in this region.
6
Ismail, Che Ain Munirah, Zakuan Zainy Deris, Ruzilawati Abu Bakar e Nabilah Ismail. "In Vitro Anti-Leptospiral Activity of Phyllanthus amarus Extracts and Their Combinations with Antibiotics". International Journal of Environmental Research and Public Health 18, n. 6 (10 marzo 2021): 2834. http://dx.doi.org/10.3390/ijerph18062834.
Testo completoAbstract (sommario):
Despite modern medicine, there is an increasing trend for cases of the bacterial infection leptospirosis, and this has led to the exploration of alternative medicines from various sources including plants. The aim of this study was to investigate the in vitro anti-leptospiral activity of Phyllanthus amarus extracts alone and combined with penicillin G, ceftriaxone, and doxycycline. Antimicrobial susceptibility testing was performed using the microdilution broth technique upon methanol extract (ME), aqueous extract (AE), and antibiotics against the Leptospira interrogans serovars Australis, Bataviae, Canicola, and Javanica, to determine minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). The results were analyzed using an ELISA microplate reader combined with microscopic analysis. Synergy testing using a checkerboard assay was performed to determine the fractional inhibitory concentration index values of extracts combined with antibiotics against leptospires. Scanning electron microscopy (SEM) was used to investigate morphological changes of leptospires caused by potential anti-leptospiral agents alone and combined with antibiotics. The MICs and MBCs for P. amarus extracts ranged from 100 to 400 µg/mL for AEs and from 400 to 800 µg/mL for MEs. Penicillin G was the most effective anti-leptospiral drug, with MICs and MBCs ranging from <0.01 to 0.78 and <0.01 to 3.13 µg/mL, respectively, followed by ceftriaxone, with both MICs and MBCs ranging from 0.05 to 0.78 µg/mL, and doxycycline, with MICs and MBCs ranging from 0.39 to 3.13 µg/mL and 12.5 to 25 µg/mL, respectively. Combinations of P. amarus extracts and antibiotics did not show synergistic effects on all tested Leptospira serovars, with some combinations demonstrating antagonistic effects. SEM analysis, however, showed distorted Leptospira surfaces. P. amarus AE performed better anti-leptospiral activity than P. amarus ME. The morphological effects of P. amarus extract alone and its combination with antibiotic on Leptospira cells revealed promising anti-leptospiral properties.
7
Cullen, Paul A., David A. Haake, Dieter M. Bulach, Richard L. Zuerner e Ben Adler. "LipL21 Is a Novel Surface-Exposed Lipoprotein of Pathogenic Leptospira Species". Infection and Immunity 71, n. 5 (maggio 2003): 2414–21. http://dx.doi.org/10.1128/iai.71.5.2414-2421.2003.
Testo completoAbstract (sommario):
ABSTRACT Leptospira is the etiologic agent of leptospirosis, a bacterial zoonosis distributed worldwide. Leptospiral lipopolysaccharide is a protective immunogen, but the extensive serological diversity of leptospires has inspired a search for conserved outer membrane proteins (OMPs) that may stimulate heterologous immunity. Previously, a global analysis of leptospiral OMPs (P. A. Cullen, S. J. Cordwell, D. M. Bulach, D. A. Haake, and B. Adler, Infect. Immun. 70:2311-2318, 2002) identified pL21, a novel 21-kDa protein that is the second most abundant constituent of the Leptospira interrogans serovar Lai outer membrane proteome. In this study, we identified the gene encoding pL21 and found it to encode a putative lipoprotein; accordingly, the protein was renamed LipL21. Southern hybridization analysis revealed the presence of lipL21 in all of the pathogenic species but in none of the saprophytic species examined. Alignment of the LipL21 sequence from six strains of Leptospira revealed 96 to 100% identity. When specific polyclonal antisera to recombinant LipL21 were used, LipL21 was isolated together with other known leptospiral OMPs by both Triton X-114 extraction and sucrose density gradient membrane fractionation. All nine strains of pathogenic leptospires investigated by Western blotting, whether culture attenuated or virulent, were found to express LipL21. In contrast, the expression of LipL21 or an antigenically related protein could not be detected in nonpathogenic L. biflexa. Infected hamster sera and two of eight human leptospirosis sera tested were found to react with recombinant LipL21. Native LipL21 was found to incorporate tritiated palmitic acid, consistent with the prediction of a lipoprotein signal peptidase cleavage site. Biotinylation of the leptospiral surface resulted in selective labeling of LipL21 and the previously known OMPs LipL32 and LipL41. These findings show that LipL21 is a surface-exposed, abundant outer membrane lipoprotein that is expressed during infection and conserved among pathogenic Leptospira species.
8
DE OLIVEIRA, D., C. P. FIGUEIRA, L. ZHAN, A. C. PERTILE, G. G. PEDRA, I. M. GUSMÃO, E. A. WUNDER et al. "Leptospira in breast tissue and milk of urban Norway rats (Rattus norvegicus)". Epidemiology and Infection 144, n. 11 (28 marzo 2016): 2420–29. http://dx.doi.org/10.1017/s0950268816000637.
Testo completoAbstract (sommario):
SUMMARYLeptospirosis is a zoonosis caused by bacteria of the genus Leptospira. The disease is globally distributed and a major public health concern. The Norway rat (Rattus norvegicus) is the main reservoir of the pathogen in urban slums of developing and developed countries. The potential routes of intra-specific leptospire transmission in rats are largely unknown. Herein, we identified pathogenic Leptospira spp. in breast tissue and milk of naturally infected rats. We examined kidney, breast tissue and milk from 24 lactating rats for the presence of leptospires using immunofluorescence, immunohistochemistry, polymerase chain reaction (PCR) and scanning electronic microscopy. All 24 rats had evidence for Leptospira in the kidneys, indicating chronic carriage. The majority of kidney-positive rats had detectable leptospires in milk (18, 75%) and breast tissue (16, 67%), as evidenced by immunofluorescence assay and immunohistochemistry. Four (17%) milk samples and two (8%) breast tissue samples were positive by quantitative real-time PCR. Scanning electron microscopy confirmed the presence of leptospires in breast tissue. No major pathological changes in breast tissue were found. This study, for the first time, identified leptospires in the milk and breast tissue of wild Norway rats, suggesting the possibility of milk-borne transmission of leptospirosis to neonates.
9
Piredda, Ivana, Maria Nicoletta Ponti, Bruna Palmas, Malgorzata Noworol, Aureliana Pedditzi, Lucio Rebechesu e Valentina Chisu. "Molecular Typing of Pathogenic Leptospira Species Isolated from Wild Mammal Reservoirs in Sardinia". Animals 11, n. 4 (13 aprile 2021): 1109. http://dx.doi.org/10.3390/ani11041109.
Testo completoAbstract (sommario):
Leptospirosis is a global zoonosis caused by pathogenic species of Leptospira that infect a large spectrum of domestic and wild animals. This study is the first molecular identification, characterization, and phylogeny of Leptospira strains with veterinary and zoonotic impact in Sardinian wild hosts. All samples collected were cultured and analyzed by multiplex real time polymerase chain reaction (qPCR). Sequencing, phylogenetic analyses (based on rrs and secY sequences), and Multilocus Sequence Typing (MLST) based on the analysis of seven concatenated loci were also performed. Results revealed the detection of Leptospira DNA and cultured isolates in 21% and 4% of the samples examined, respectively. Sequence analysis of Leptospira positive samples highlighted the presence of the interrogans and borgpetersenii genospecies that grouped in strongly supported monophyletic clades. MLST analyses identified six different Sequence Types (ST) that clustered in two monophyletic groups specific for Leptospirainterrogans, and L. borgpetersenii. This study provided about the prevalence of leptospires in wild mammals in Sardinia, and increased our knowledge of this pathogen on the island. Monitoring Leptospira strains circulating in Sardinia will help clinicians and veterinarians develop strategic plans for the prevention and control of leptospiral infections.
10
Kamaruzaman, Intan, Muhamad Mokhtar, Hong Ting, Yong Yuan, Azim Shah, Tan Loong, Nurshahirah Shaharulnizim et al. "Molecular detection of pathogenic Leptospira spp. in urban rodents from wet markets in northeast Malaysia". Journal of Advanced Veterinary and Animal Research 9, n. 2 (2022): 275. http://dx.doi.org/10.5455/javar.2022.i593.
Testo completoAbstract (sommario):
Objective: This short study describes the occurrence of pathogenic Leptospira spp. in two major wet markets in Kota Bharu, Kelantan, Malaysia. Materials and Methods: 30 rodents (20 rats and 10 shrews) were caught in 2 wet markets, and a postmortem was performed to extract both kidneys. Molecular diagnosis via polymerase chain reaction (PCR) was conducted to detect leptospiral DNA using universal and pathogenic Leptospira primers, respectively. Results: The results showed that 20/28 (72%) rat samples were detected positive for Leptospira spp, and all shrews were negative. Further sequencing analysis identified L. interrogans and L. borgpetersenii as the most frequently Leptospirosis species from kidney samples. Conclusions: The presented study here sheds light on the presence of pathogenic leptospires har¬boring the rat population in both wet markets in Kelantan, which presents a great public health risk to wet market workers and visitors.
11
Santos, Ana Amélia Nunes, Priscyla dos Santos Ribeiro, Geórgia Virgínia da França, Fábio Neves Souza, Eduardo Antônio Gonçalves Ramos, Cláudio Pereira Figueira, Mitermayer G. Reis, Federico Costa e Paula Ristow. "Leptospira interrogans biofilm formation in Rattus norvegicus (Norway rats) natural reservoirs". PLOS Neglected Tropical Diseases 15, n. 9 (8 settembre 2021): e0009736. http://dx.doi.org/10.1371/journal.pntd.0009736.
Testo completoAbstract (sommario):
Rattus norvegicus (Norway rat) is the main reservoir host of pathogenic Leptospira, the causative agent of leptospirosis, in urban environments. Pathogenic Leptospira forms biofilms in the environment, possibly contributing for bacterial survival and maintenance. Nonetheless, biofilms have not yet been studied in natural animal reservoirs presenting leptospiral renal carriage. Here, we described biofilm formation by pathogenic Leptospira inside the renal tubules of R. norvegicus naturally infected and captured in an urban slum endemic for leptospirosis. From the 65 rats carrying Leptospira in their kidneys, 24 (37%) presented biofilms inside the renal tubules. The intensity of leptospiral colonization in the renal tubules (OR: 1.00; 95% CI 1.05–1.1) and the type of occlusion pattern of the colonized renal tubules (OR: 3.46; 95% CI 1.20–9.98) were independently associated with the presence of Leptospira biofilm. Our data showed that Leptospira interrogans produce biofilms during renal chronic colonization in rat reservoirs, suggesting a possible role for leptospiral biofilms in the pathogenesis of leptospirosis and bacterial carriage in host reservoirs.
12
Matsunaga, James, Kristian Werneid, Richard L. Zuerner, Ami Frank e David A. Haake. "LipL46 is a novel surface-exposed lipoprotein expressed during leptospiral dissemination in the mammalian host". Microbiology 152, n. 12 (1 dicembre 2006): 3777–86. http://dx.doi.org/10.1099/mic.0.29162-0.
Testo completoAbstract (sommario):
Leptospirosis is a widespread zoonosis caused by invasive spirochaetes belonging to the genus Leptospira. Pathogenic leptospires disseminate via the bloodstream to colonize the renal tubules of reservoir hosts. Little is known about leptospiral outer-membrane proteins expressed during the dissemination stage of infection. In this study, a novel surface-exposed lipoprotein is described; it has been designated LipL46 to distinguish it from a previously described 31 kDa peripheral membrane protein, P31LipL45, which is exported as a 45 kDa probable lipoprotein. The lipL46 gene encodes a 412 aa polypeptide with a 21 aa signal peptide. Lipid modification of cysteine at the lipoprotein signal peptidase cleavage site FSISC is supported by the finding that Leptospira interrogans intrinsically labels LipL46 during incubation in medium containing [14C]palmitate. LipL46 appears to be exported to the leptospiral outer membrane as a 46 kDa lipoprotein, based on Triton X-114 solubilization and phase partitioning studies, which included the outer and inner membrane controls LipL32 and LipL31, respectively. Surface immunoprecipitation and whole-cell ELISA experiments indicate that LipL46 is exposed on the leptospiral surface. Immunohistochemistry studies demonstrated expression of LipL46 by leptospires found in the bloodstream of acutely infected hamsters. Leptospires expressing LipL46 were also found in the intercellular spaces of the liver, within splenic phagocytes, and invading the glomerular hilum of the kidney. Infection-associated expression is supported by the finding that LipL46 is a major antigen recognized by sera from infected hamsters. These findings indicate that LipL46 may be important in leptospiral dissemination, and that it may serve as a useful serodiagnostic antigen.
13
Chaiwattanarungruengpaisan, Somjit, Wasinee Thepapichaikul, Weena Paungpin, Kanokwan Ketchim, Sarin Suwanpakdee e Metawee Thongdee. "Potentially Pathogenic Leptospira in the Environment of an Elephant Camp in Thailand". Tropical Medicine and Infectious Disease 5, n. 4 (6 dicembre 2020): 183. http://dx.doi.org/10.3390/tropicalmed5040183.
Testo completoAbstract (sommario):
Leptospira is the causative agent of leptospirosis, a globally emerging zoonotic disease. The infection is commonly acquired through contact with the contaminated environment. To extend the knowledge on environmental source of leptospirosis, we investigated the presence of Leptospira in an elephant camp setting where the interaction between humans, animals, and the shared environment occur particularly when engaging in recreational activities. In this study, a total of 24 environmental samples were collected from an elephant camp area in western Thailand. All samples were processed for Leptospira isolation using the EMJH medium. The identification of Leptospira species was carried out by partial 16S rRNA and secY gene sequencing. Of those 24 samples, 18 samples (75%) were culture-positive for Leptospira. The recovered leptospires were mostly derived from water and soil sampled from a river and a mud pond, the main areas for recreational activities. The majority of the isolates were classified into “Pathogens” clade (89%, 16/18) and more than half of the isolates (61%, 11/18) contained species of the “Saprophytes” clade. Notably, two soil isolates from the river beach sampling area were found to contain leptospiral DNA with high similarity to the pathogenic L. interrogans and L. santarosai. The evidence of diverse Leptospira species, particularly those belonging to the “Pathogens” clade, suggest that the shared environments of an elephant camp can serve as potential infection source and may pose a risk to the elephant camp tourists and workers.
14
Kiuno, Kazuki, Takuya Kato, Hiroko Otsubo, Ryoko Kibe, Yasushi Kataoka e Shin-ichi Hayama. "Epidemiological Study of Pathogenic Leptospira in Raccoons (Procyon lotor) in a Suburb of Tokyo, Japan". Animals 13, n. 1 (21 dicembre 2022): 21. http://dx.doi.org/10.3390/ani13010021.
Testo completoAbstract (sommario):
Leptospirosis is a zoonosis that affects humans and animals worldwide. Raccoons (Procyon lotor), adopted in urban environments, may act as potential reservoirs of Leptospira. We investigated the prevalence of pathogenic Leptospira in the kidney and urine samples of raccoons living in Tokyo, as well as anti-leptospiral antibodies in their serum, and aimed to examine the factors that expose raccoons to Leptospira. Polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect leptospiral DNA and anti-leptospiral antibodies, respectively. Thirty-six of 156 raccoons (23.1%) were positive by PCR, and 16 of 165 raccoons (9.7%) were positive by ELISA. The prevalence and seroprevalence rates differed depending on the raccoon dispersal period. We used univariable logistic regression to estimate the environmental factors associated with pathogenic Leptospira and anti-leptospiral antibodies in raccoons. Significant differences were observed in the PCR results for the seasons (spring–summer) (p = 0.01), average monthly temperature (p < 0.01), and average monthly rainfall (p < 0.01). No significant difference was seen in the ELISA results, but raccoons in larger urban areas tended to have higher seroprevalence rates (p = 0.06). We identified a pattern of leptospiral spread in raccoon dispersal and environmental factors that expose raccoons to Leptospira.
15
Palaniappan, Raghavan U. M., Yung-Fu Chang, S. S. D. Jusuf, S. Artiushin, John F. Timoney, Sean P. McDonough, Steve C. Barr et al. "Cloning and Molecular Characterization of an Immunogenic LigA Protein of Leptospira interrogans". Infection and Immunity 70, n. 11 (novembre 2002): 5924–30. http://dx.doi.org/10.1128/iai.70.11.5924-5930.2002.
Testo completoAbstract (sommario):
ABSTRACT A clone expressing a novel immunoreactive leptospiral immunoglobulin-like protein A of 130 kDa (LigA) from Leptospira interrogans serovar pomona type kennewicki was isolated by screening a genomic DNA library with serum from a mare that had recently aborted due to leptospiral infection. LigA is encoded by an open reading frame of 3,675 bp, and the deduced amino acid sequence consists of a series of 90-amino-acid tandem repeats. A search of the NCBI database found that homology of the LigA repeat region was limited to an immunoglobulin-like domain of the bacterial intimin binding protein of Escherichia coli, the cell adhesion domain of Clostridium acetobutylicum, and the invasin of Yersinia pestis. Secondary structure prediction analysis indicates that LigA consists mostly of beta sheets with a few alpha-helical regions. No LigA was detectable by immunoblot analysis of lysates of the leptospires grown in vitro at 30°C or when cultures were shifted to 37°C. Strikingly, immunohistochemistry on kidney from leptospira-infected hamsters demonstrated LigA expression. These findings suggest that LigA is specifically induced only in vivo. Sera from horses, which aborted as a result of natural Leptospira infection, strongly recognize LigA. LigA is the first leptospiral protein described to have 12 tandem repeats and is also the first to be expressed only during infection. Thus, LigA may have value in serodiagnosis or as a protective immunogen in novel vaccines.
16
Matsunaga, James, Miranda Lo, Dieter M. Bulach, Richard L. Zuerner, Ben Adler e David A. Haake. "Response of Leptospira interrogans to Physiologic Osmolarity: Relevance in Signaling the Environment-to-Host Transition". Infection and Immunity 75, n. 6 (19 marzo 2007): 2864–74. http://dx.doi.org/10.1128/iai.01619-06.
Testo completoAbstract (sommario):
ABSTRACT Transmission of pathogenic Leptospira between mammalian hosts usually involves dissemination via soil or water contaminated by the urine of carrier animals. The ability of Leptospira to adapt to the diverse conditions found inside and outside the host is reflected in its relatively large genome size and high percentage of signal transduction genes. An exception is Leptospira borgpetersenii serovar Hardjo, which is transmitted by direct contact and appears to have lost genes necessary for survival outside the mammalian host. Invasion of host tissues by Leptospira interrogans involves a transition from a low osmolar environment outside the host to a higher physiologic osmolar environment within the host. Expression of the lipoprotein LigA and LigB adhesins is strongly induced by an upshift in osmolarity to the level found in mammalian host tissues. These data suggest that Leptospira utilizes changes in osmolarity to regulate virulence characteristics. To better understand how L. interrogans serovar Copenhageni adapts to osmolar conditions that correspond with invasion of a mammalian host, we quantified alterations in transcript levels using whole-genome microarrays. Overnight exposure in leptospiral culture medium supplemented with sodium chloride to physiologic osmolarity significantly altered the transcript levels of 6% of L. interrogans genes. Repressed genes were significantly more likely to be absent or pseudogenes in L. borgpetersenii, suggesting that osmolarity is relevant in studying the adaptation of L. interrogans to host conditions. Genes induced by physiologic osmolarity encoded a higher than expected number of proteins involved in signal transduction. Further, genes predicted to encode lipoproteins and those coregulated by temperature were overrepresented among both salt-induced and salt-repressed genes. In contrast, leptospiral homologues of hyperosmotic or general stress genes were not induced at physiologic osmolarity. These findings suggest that physiologic osmolarity is an important signal for regulation of gene expression by pathogenic leptospires during transition from ambient conditions to the host tissue environment.
17
Verma, Ashutosh, Sergey Artiushin, James Matsunaga, David A. Haake e John F. Timoney. "LruA and LruB, Novel Lipoproteins of Pathogenic Leptospira interrogans Associated with Equine Recurrent Uveitis". Infection and Immunity 73, n. 11 (novembre 2005): 7259–66. http://dx.doi.org/10.1128/iai.73.11.7259-7266.2005.
Testo completoAbstract (sommario):
ABSTRACT Recurrent uveitis as a sequela to Leptospira infection is the most common infectious cause of blindness and impaired vision of horses worldwide. Leptospiral proteins expressed during prolonged survival in the eyes of horses with lesions of chronic uveitis were identified by screening a phage library of Leptospira interrogans DNA fragments with eye fluids from uveitic horses. Inserts of reactive phages encoded several known leptospiral proteins and two novel putative lipoproteins, LruA and LruB. LruA was intrinsically labeled during incubation of L. interrogans in medium containing [14C]palmitic acid, confirming that it is a lipoprotein. lruA and lruB were detected by Southern blotting in infectious Leptospira interrogans but not in nonpathogenic Leptospira biflexa. Fractionation data from cultured Leptospira indicate that LruA and LruB are localized in the inner membrane. Uveitic eye fluids contained significantly higher levels of immunoglobulin A (IgA) and IgG specific for each protein than did companion sera, indicating strong local antibody responses. Moreover, LruA- and LruB-specific antisera reacted with equine ocular components, suggesting an immunopathogenic role in leptospiral uveitis.
18
Techawiwattanaboon, Barnier-Quer, Palaga, Jacquet, Collin, Sangjun, Komanee, Piboonpocanun e Patarakul. "Reduced Renal Colonization and Enhanced Protection by Leptospiral Factor H Binding Proteins as a Multisubunit Vaccine Against Leptospirosis in Hamsters". Vaccines 7, n. 3 (22 agosto 2019): 95. http://dx.doi.org/10.3390/vaccines7030095.
Testo completoAbstract (sommario):
Subunit vaccines conferring complete protection against leptospirosis are not currently available. The interactions of factor H binding proteins (FHBPs) on pathogenic leptospires and host factor H are crucial for immune evasion by inhibition of complement-mediated killing. The inhibition of these interactions may be a potential strategy to clear leptospires in the host. This study aimed to evaluate a multisubunit vaccine composed of four known leptospiral FHBPs: LigA domain 7–13 (LigAc), LenA, LcpA, and Lsa23, for its protective efficacy in hamsters. The mono and multisubunit vaccines formulated with LMQ adjuvant, a combination of neutral liposome, monophosphoryl lipid A, and Quillaja saponaria fraction 21, induced high and comparable specific antibody (IgG) production against individual antigens. Hamsters immunized with the multisubunit vaccine showed 60% survival following the challenge by 20 LD50 of Leptospira interrogans serovar Pomona. No significant difference in survival rate and pathological findings of target organs was observed after vaccinations with multisubunit or mono-LigAc vaccines. However, the multisubunit vaccine significantly reduced leptospiral burden in surviving hamsters in comparison with the monosubunit vaccines. Therefore, the multisubunit vaccine conferred partial protection and reduced renal colonization against virulence Leptospira infection in hamsters. Our multisubunit formulation could represent a promising vaccine against leptospirosis.
19
Monahan, Avril M., John J. Callanan e Jarlath E. Nally. "Proteomic Analysis of Leptospira interrogans Shed in Urine of Chronically Infected Hosts". Infection and Immunity 76, n. 11 (2 settembre 2008): 4952–58. http://dx.doi.org/10.1128/iai.00511-08.
Testo completoAbstract (sommario):
ABSTRACT Leptospirosis is a global zoonotic disease. The causative agent, pathogenic Leptospira species, survives in the renal tubules of chronically infected hosts, from where leptospires are shed via urine into the environment. Infection of new hosts can present as an array of acute and chronic disease processes reflecting variations in host-pathogen interactions. The present study was designed to reproduce the carrier phase of infection in Rattus norvegicus, thus facilitating shedding of leptospires in urine. Leptospires shed in urine were collected for proteomic analysis because these organisms reflect a naturally virulent form of Leptospira associated with infection of new hosts. Experimentally infected rats remained clinically asymptomatic but shed leptospires in urine for several months at concentrations of up to 107 leptospires/ml of urine. Proteomic analysis of rat urine-isolated leptospires compared to in vitro-cultivated leptospires confirmed differential protein and antigen expression, as demonstrated by two-dimensional gel electrophoresis and immunoblotting. Furthermore, while serum from chronically infected rats reacted with many antigens of in vitro-cultivated Leptospira, few antigens of rat urine-isolated Leptospira were reactive. Results confirm that differential protein expression by Leptospira during chronic infection facilitates its persistence in the presence of a specific host antibody response.
20
Barbosa, Angela S., Patricia A. E. Abreu, Sílvio A. Vasconcellos, Zenaide M. Morais, Amane P. Gonçales, Aldacilene S. Silva, Mohamed R. Daha e Lourdes Isaac. "Immune Evasion of Leptospira Species by Acquisition of Human Complement Regulator C4BP". Infection and Immunity 77, n. 3 (29 dicembre 2008): 1137–43. http://dx.doi.org/10.1128/iai.01310-08.
Testo completoAbstract (sommario):
ABSTRACT Leptospirosis is a spirochetal zoonotic disease of global distribution with a high incidence in tropical regions. In the last 15 years it has been recognized as an important emerging infectious disease due to the occurrence of large outbreaks in warm-climate countries and, occasionally, in temperate regions. Pathogenic leptospires efficiently colonize target organs after penetrating the host. Their invasiveness is attributed to the ability to multiply in blood, adhere to host cells, and penetrate into tissues. Therefore, they must be able to evade the innate host defense. The main purpose of the present study was to evaluate how several Leptospira strains evade the protective function of the complement system. The serum resistance of six Leptospira strains was analyzed. We demonstrate that the pathogenic strain isolated from infected hamsters avoids serum bactericidal activity more efficiently than the culture-attenuated or the nonpathogenic Leptospira strains. Moreover, both the alternative and the classical pathways of complement seem to be responsible for the killing of leptospires. Serum-resistant and serum-intermediate strains are able to bind C4BP, whereas the serum-sensitive strain Patoc I is not. Surface-bound C4BP promotes factor I-mediated cleavage of C4b. Accordingly, we found that pathogenic strains displayed reduced deposition of the late complement components C5 to C9 upon exposure to serum. We conclude that binding of C4BP contributes to leptospiral serum resistance against host complement.
21
Vieira, Monica L., Silvio A. Vasconcellos, Amane P. Gonçales, Zenaide M. de Morais e Ana L. T. O. Nascimento. "Plasminogen Acquisition and Activation at the Surface of Leptospira Species Lead to Fibronectin Degradation". Infection and Immunity 77, n. 9 (6 luglio 2009): 4092–101. http://dx.doi.org/10.1128/iai.00353-09.
Testo completoAbstract (sommario):
ABSTRACT Pathogenic Leptospira species are the etiological agents of leptospirosis, a widespread disease of human and veterinary concern. In this study, we report that Leptospira species are capable of binding plasminogen (PLG) in vitro. The binding to the leptospiral surface was demonstrated by indirect immunofluorescence confocal microscopy with living bacteria. The PLG binding to the bacteria seems to occur via lysine residues because the ligation is inhibited by addition of the lysine analog 6-aminocaproic acid. Exogenously provided urokinase-type PLG activator (uPA) converts surface-bound PLG into enzymatically active plasmin, as evaluated by the reaction with the chromogenic plasmin substrate d-Val-Leu-Lys 4-nitroanilide dihydrochloridein. The PLG activation system on the surface of Leptospira is PLG dose dependent and does not cause injury to the organism, as cellular growth in culture was not impaired. The generation of active plasmin within Leptospira was observed with several nonvirulent high-passage strains and with the nonpathogenic saprophytic organism Leptospira biflexa. Statistically significant higher activation of plasmin was detected with a low-passage infectious strain of Leptospira. Plasmin-coated virulent Leptospira interrogans bacteria were capable of degrading purified extracellular matrix fibronectin. The breakdown of fibronectin was not observed with untreated bacteria. Our data provide for the first time in vitro evidence for the generation of active plasmin on the surface of Leptospira, a step that may contribute to leptospiral invasiveness.
22
Chagas-Junior, Adenizar D., Alan J. A. McBride, Daniel A. Athanazio, Cláudio P. Figueira, Marco A. Medeiros, Mitermayer G. Reis, Albert I. Ko e Flávia W. C. McBride. "An imprint method for detecting leptospires in the hamster model of vaccine-mediated immunity for leptospirosis". Journal of Medical Microbiology 58, n. 12 (1 dicembre 2009): 1632–37. http://dx.doi.org/10.1099/jmm.0.014050-0.
Testo completoAbstract (sommario):
In determining the efficacy of new vaccine candidates for leptospirosis, the primary end point is death and an important secondary end point is sterilizing immunity. However, evaluation of this end point is often hampered by the time-consuming demands and complexity of methods such as culture isolation (CI). In this study, we evaluated the use of an imprint (or touch preparation) method (IM) in detecting the presence of leptospires in tissues of hamsters infected with Leptospira interrogans serovar Copenhageni. In a dissemination study, compared to CI, the IM led to equal or improved detection of leptospires in kidney, liver, lung and blood samples collected post-infection and overall concordance was good (κ=0.61). Furthermore, in an evaluation of hamsters immunized with a recombinant leptospiral protein-based vaccine candidate and subsequently challenged, the agreement between the CI and IM was very good (κ=0.84). These findings indicate that the IM is a rapid method for the direct observation of Leptospira spp. that can be readily applied to evaluating infection in experimental animals and determining sterilizing immunity when screening potential vaccine candidates.
23
Ackermann, Kerstin, Rebecca Kenngott, Monica Settles, Hartmut Gerhards, Johann Maierl e Bettina Wollanke. "In Vivo Biofilm Formation of Pathogenic Leptospira spp. in the Vitreous Humor of Horses with Recurrent Uveitis". Microorganisms 9, n. 9 (9 settembre 2021): 1915. http://dx.doi.org/10.3390/microorganisms9091915.
Testo completoAbstract (sommario):
Equine recurrent uveitis (ERU) causes painful inflammatory attacks and oftentimes blindness in the affected eyes. The disease is considered a late sequela of systemic leptospirosis. The most effective therapy is the surgical removal of the vitreous (vitrectomy), which is not only therapeutic, but provides vitreous material that can be assessed diagnostically. For example, the lipL32 gene, culturable Leptospira spp., and anti-Leptospira antibodies have all been detected in vitreous samples obtained from eyes with chronic ERU. Despite this clear evidence of leptospiral involvement, the systemic administration of antibiotics in infected horses is ineffective at resolving ERU. This syndrome of chronic recurrent inflammation, which is unresponsive to antibiotic therapy, combined with apparent bacteria evading the immune response, is consistent with a biofilm-associated infection. The purpose of this study, therefore, was to detect the in vivo biofilm formation of Leptospira spp. in vitreous samples collected during vitrectomy and examined using a Warthin-Starry silver stain and immunohistochemistry. All known steps of biofilm formation were visualized in these samples, including individual Leptospira spp., leptospiral microcolonies and dense roundish accumulations of Leptospira spp. In many instances spirochetes were surrounded by an extracellular substance. Taken together, data from the present study show that ERU is a biofilm-associated intraocular leptospiral infection, which best explains the typical clinical course.
24
Franco, Alieksandr Karnauchovas, José Victor Pronievicz Barreto, Bruna Fonseca Matias, Daiane Andreola, Francisco Thiago Vieira Oliveira, José Gustavo Monteiro Minguetto, Marcela Lucas de Lima et al. "Leptospirose em Ovinos: Revisão Clínico Microbiológica". Ensaios e Ciência C Biológicas Agrárias e da Saúde 24, n. 5-esp. (19 febbraio 2021): 462–68. http://dx.doi.org/10.17921/1415-6938.2020v24n5-esp.p462-468.
Testo completoAbstract (sommario):
A leptospirose é uma zoonose causada por uma bactéria do gênero Leptospira. Trata-se de uma enfermidade infecciosa de distribuição mundial, de ocorrência maior em países de clima tropical e subtropical, principalmente, nos períodos mais chuvosos, quando existem condições ambientais, que aumentam a sobrevivência da bactéria no ambiente. Esta enfermidade acomete os seres humano e, praticamente, todos os animais domésticos e selvagens, que podem se tornar portadores e contribuírem para a disseminação do micro-organismo na natureza. Nos ovinos, a enfermidade pode provocar falhas reprodutivas e abortamentos, morte de cordeiros, inanição, infecção grave, febre e insuficiência hepática e/ou renal. Este trabalho teve como objetivo revisar importantes aspectos sobre a leptospirose em ovinos, abordando sobre o histórico, etiologia, epidemiologia, patogenia, sinais clínicos, diagnóstico, tratamento, controle e prevenção. Foram lidos 58 trabalhos publicados, a busca ocorreu através de portais indexadores e livros, que citam como descritores as palavras: lepstospiras em animais, Leptospiras em ovinos, sorovares de Leptospiras, leptospirose em ovinos. A compreensão de todos os fatores envolvidos na leptospirose em ovinos é uma condição fundamental para a adoção de medidas estratégicas médicas e epidemiológicas, que possibilitem o controle e a prevenção da doença nos rebanhos, evitando assim queda na produtividade e redução dos prejuízos econômicos.
Palavras-chave: Leptospira spp. MAT Zoonoses.
Abstract
Leptospirosis is a zoonosis caused by a bacterium of the genus Leptospira. It is an infectious disease worldwidely distributed, occurring more frequently in countries with tropical and subtropical climates, especially in the rainiest periods, when there are environmental conditions that increase the bacteria survival in the environment. This disease affects humans and most of the domestic and wild animals, which can become carriers and contribute to the microorganism spread in nature. In sheep, the disease can cause reproductive failures and miscarriages, lamb death, starvation, severe infection, fever and liver and / or kidney failure. This work aimed to review important aspects about leptospirosis in sheep, addressing the history, etiology, epidemiology, pathogenesis, clinical signs, diagnosis, treatment, control and prevention. 58 published works were read, the search was performed through indexing portals and books that mention the words as descriptors: leptospirae in animals, leptospirae in sheep, serovars of leptospirae, leptospirosis in sheep. Understanding all the factors involved in leptospirosis in sheep is a fundamental condition for the adoption of strategic medical and epidemiological measures that enable the disease control and prevention in herds, thus avoiding a fall in productivity and a reduction in economic losses.
Keywords: Leptospira spp. MAT. Zoonosis.
25
Thayaparan, Siva, Ian Robertson, Fairuz Amraan, Lela Su'ut e Mohd Tajuddin Abdullah. "Serological Prevalence of Leptospiral Infection in Wildlife in Sarawak, Malaysia". Borneo Journal of Resource Science and Technology 2, n. 2 (29 giugno 2016): 71–74. http://dx.doi.org/10.33736/bjrst.281.2013.
Testo completoAbstract (sommario):
Leptospirosis is a zoonotic disease caused by pathogenic leptospiral bacteria, which are transmitted directly orindirectly from animals to humans or animal to animal. The first phase of this proposed study was carried out todetermine the extent of exposure to leptospirosis in wild mammals surrounded by human settlements aroundwildlife or tourism area (Wind Cave, Fairy Cave, Bako National Park and Matang Wildlife Center). This studyreports an incident of leptospirosis among primates (three captive and two free ranging), rats, bats, squirrels andmongoose around Kuching, Sarawak area, which has been screened for Leptospirosis. Blood samples wereobtained to determine the presence of antibodies through the microscopic agglutination test (MAT) usingeighteen serovars of Leptospira commonly found in Malaysia as antigens. It was observed that four out of thefive monkeys (80%), rats (9/4) (44%), bats (20/5) (20.8%), squirrels 4/4 (100%) and mongoose (1) (100%)reacted against one or more serovars of Leptospira. In this study antibody of five serovars of Leptospirainterrrogans Copenheni, Leptospira interrrogans Lai, Leptospira interrrogans Pomona, Leptospira interrrogansPyrogenes, Lepto 175* were detected. Serovars Copenhegeni, Lai, Pomona and Pyrogenes were consideredpathogenic for different mammals including human beings. No information about serovars lepto 175 and furtherstudies going on. This is providing information on the possible zoonotic importance of mammalian species inmaintaining this disease in Sarawak. The transmission of leptospires in rats reported several incidents andbetween primates, bats, squirrels, mongoose and human is not reported elsewhere but this could create newreservoir and transmission routes and may affect the tourism, conservation effort and public health.
26
Scanziani, E., L. Crippa, Anna M. Giusti, M. Luini, Maria L. Pacciarini, Silvia Tagliabue e E. Cavalletti. "Leptospira interrogans serovar sejroe infection in a group of laboratory dogs". Laboratory Animals 29, n. 3 (1 luglio 1995): 300–306. http://dx.doi.org/10.1258/002367795781088261.
Testo completoAbstract (sommario):
Interstitial nephritis was seen histologically in 19 (59%) out of 32 pure-breed beagle dogs (16 males and 16 females) subjected to standard safety tests. In these animals no clinical abnormalities were observed and all the tested parameters (haematology, biochemistry and urine analysis) were within the normal ranges. Leptospiral antibody titres ranging from 1:100 to 1:6400, against a serovar ( hardio) belonging to the Sejroe serogroup, were detected by the microscopic agglutination test (MAT) in the serum of the 19 dogs with interstitial nephritis. All animals without renal lesions were seronegative. Leptospiral antigen was detected immunohistochemically in the kidneys of 4 dogs; leptospires were detected in Warthin-Starry stained sections of one dog. Leptospires were isolated from the kidneys of 3 of the 4 dogs examined by bacterial culture. The isolated strains were typed as serovar sejroe by restriction endonuclease digestion and Southern blot hybridization analysis of their DNA. It was concluded that Leptospira interrogans serovar sejroe, was responsible for an asymptomatic chronic renal infection which was widespread in this group of laboratory dogs.
27
Verma, Ashutosh, Esteban Soto, Oscar Illanes, Souvik Ghosh e Carmen Fuentealba. "Detection and genotyping of Leptospira spp. from the kidneys of a seemingly healthy pig slaughtered for human consumption". Journal of Infection in Developing Countries 9, n. 05 (18 maggio 2015): 530–32. http://dx.doi.org/10.3855/jidc.5727.
Testo completoAbstract (sommario):
Introduction: Leptospirosis is a zoonotic disease caused by pathogenic Leptospira spp. Leptospirosis is maintained in an environment due to chronic kidney infection of a wide variety of domestic, peridomestic and wild reservoir mammals. In this study the role of pigs in maintenance of leptospires on the Caribbean island of St. Kitts was investigated. Methodology: The condemned kidneys of 60 pigs slaughtered at a St. Kitts abattoir were screened by a quantitative-PCR for the presence of Leptospira spp. Positive samples were genotyped using a six-gene based multilocus sequence typing scheme. Results: Leptospiral DNA was detected in the kidneys of one of the 60 pigs. Multilocus sequence typing identified the infecting species to be L. interrogans. Conclusions: Detection of this zoonotic pathogen in the kidneys of a seemingly healthy pig raises concerns regarding the subclinical carriers of the disease among the island’s swine population.
28
Branger, C., C. Sonrier, B. Chatrenet, B. Klonjkowski, N. Ruvoen-Clouet, A. Aubert, G. André-Fontaine e M. Eloit. "Identification of the Hemolysis-Associated Protein 1 as a Cross-Protective Immunogen of Leptospira interrogans by Adenovirus-Mediated Vaccination". Infection and Immunity 69, n. 11 (1 novembre 2001): 6831–38. http://dx.doi.org/10.1128/iai.69.11.6831-6838.2001.
Testo completoAbstract (sommario):
ABSTRACT New vaccine strategies are needed for the prevention of leptospirosis, a widespread human and animal disease caused by pathogenic leptospires. Our previous work determined that a protein leptospiral extract conferred cross-protection in a gerbil model of leptospirosis. The 31- to 34-kDa protein fraction of Leptospira interrogans serovar autumnalis was shown sufficient for this purpose. In the present study, N-terminal sequencing of a 32-kDa fraction and Southern blotting of genomic DNA with corresponding degenerated oligonucleotide probes identified two of its constituents: hemolysis-associated protein 1 (Hap1) and the outer membraneLeptospira protein 1 (OmpL1). Adenovirus-mediated Hap1 vaccination induces significant protection against a virulent heterologous Leptospira challenge in gerbils, whereas a similar OmpL1 construct failed to protect the animals. These data indicate that Hap1 could be a good candidate for developing a new generation of vaccines able to induce broad protection against leptospirosis disease.
29
Taseva, Evgenia, Iva Christova, Elitsa Panayotova e Iva Trifonova. "INVESTIGATION OF MURINE RODENTS FOR THE PRESENCE OF LEPTOSPIRA DNA BY NESTED PCR". PROBLEMS of Infectious and Parasitic Diseases 47, n. 1 (27 giugno 2019): 25–29. http://dx.doi.org/10.58395/pipd.v47i1.14.
Testo completoAbstract (sommario):
Leptospirosis is a zooanthroponosis with natural foci. People become infected with leptospires either directly from host animals or by means of certain elements of the external environment. Circulation of leptospires in nature is maintained by reservoirs and supporting hosts. For the first time in Bulgaria we applied nested PCR in examining organs of murine rodents for the presence of Leptospira spp. DNA. A total of 109 rodents were investigated after being collected from 4 districts in Southern Bulgaria: Plovdiv, Pazardzhik, Smolyan and Blagoevgrad. The genome of Leptospira spp. was found in 5 species of rodents. Results show that Microtus spp. is a potential carrier of leptospires, especially in urban areas. The high rate of leptospiral DNA-positive rodents captured in the region of Pazardzhik confirms the activity of the epizootic process in this natural focus, where epidemics of benign leptospirosis have been recorded in the past. The introduced method would help to clarify the epidemiological links more quickly in case of a leptospirosis outbreak in some regions. Stronger measures are needed to combat rats, murine rodents and their entry in warehouses, slaughterhouses and mass caterers, in order to maintain the cleanliness of open-air ponds, water sources and prevent contamination of food products. Future studies in this area would enrich the knowledge on the circulation of leptospires in their reservoirs in more areas of our country.
30
Asoh, Tatsuma, Mitsumasa Saito, Sharon Y. A. M. Villanueva, Takaaki Kanemaru, Nina Gloriani e Shin-ichi Yoshida. "Natural defense by saliva and mucosa against oral infection by Leptospira". Canadian Journal of Microbiology 60, n. 6 (giugno 2014): 383–89. http://dx.doi.org/10.1139/cjm-2014-0016.
Testo completoAbstract (sommario):
Leptospirosis caused by drinking water has not been as frequently reported as percutaneous infection. Resistance to oral infection by pathogenic Leptospira was examined in an experimental hamster infection model. The results suggested some natural defenses against oral infection by Leptospira. First, we found that characteristic linear agglutination of Leptospira rapidly occurs when mixed with human saliva. That human saliva attenuated the infectivity of the treated leptospires by its agglutination activity suggested saliva to be the first line of defense against oral infection by leptospires. Second, only 101 Leptospira organisms caused death after submucosal injection into oral mucosa in hamsters, but oral infection with drinking water containing 105 organisms/mL did not cause death. This result showed that the mucosa plays the role of a physical barrier. Third, hamsters intragastrically infected by leptospires, with doses lethal to hamsters in oral infection, showed no signs of illness, which suggested that gastric acid plays an important role in preventing oral infection. Based on these results, saliva, mucosa, and gastric acid make up a natural defense, which confers high resistance to hosts against oral infection by leptospires.
31
Zhang, Xiang-Yan, Yang Yu, Ping He, Yi-Xuan Zhang, Bao-Yu Hu, Yang Yang, Yi-Xin Nie, Xiu-Gao Jiang, Guo-Ping Zhao e Xiao-Kui Guo. "Expression and Comparative Analysis of Genes Encoding Outer Membrane Proteins LipL21, LipL32 and OmpL1 in Epidemic Leptospires". Acta Biochimica et Biophysica Sinica 37, n. 10 (1 ottobre 2005): 649–56. http://dx.doi.org/10.1111/j.1745-7270.2005.00094.x.
Testo completoAbstract (sommario):
AbstractLeptospiral outer membrane proteins (OMPs) are highly conserved in different species, and play an essential role in the development of new immunoprotection and serodiagnosis strategies. The genes encoding LipL21, LipL32 and OmpL1 were cloned from the complete genome sequence of Leptospira interrogans serovar lai strain Lai and expressed in vitro. Sequence comparison analysis revealed that the three genes were highly conserved among distinct epidemic leptospires, including three major epidemic species Leptospira interrogans, Leptospira borgpetersenii and Leptospira weilii, in China. Immunoblot analysis was further performed to scrutinize 15 epidemic Leptospira reference strains using the antisera of the recombinant OMPs. Both immunoblot assay and reverse transcription-polymerase chain reaction demonstrated that these three OMPs were conservatively expressed in pathogenic L. interrogans strains and other pathogenic leptospires. Additionally, the use of these recombinant OMPs as antigens in enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of leptospirosis was evaluated. The recombinant LipL32 and OmpL1 proteins showed a high degree of ELISA reactivity with sera from patients infected with L. interrogans strain Lai and other pathogenic leptospires. These results may contribute to the identification of candidates for broad-range vaccines and immunodiagnostic antigens in further research.
32
Liu, Dongyou, Mark L. Lawrence, Frank W. Austin, A. Jerald Ainsworth e Lanny W. Pace. "PCR detection of pathogenic Leptospira genomospecies targeting putative transcriptional regulator genes". Canadian Journal of Microbiology 52, n. 3 (1 marzo 2006): 272–77. http://dx.doi.org/10.1139/w05-120.
Testo completoAbstract (sommario):
The genus Leptospira comprises multiple genomospecies that demonstrate varied pathogenic potential. The availability of rapid and precise diagnostic procedures to differentiate pathogenic from nonpathogenic Leptospira spp. is therefore essential to prevent an otherwise easily treatable malaise from developing into a life-threatening disease. In this report, we conducted an investigation on the diagnostic potential of Leptospira genes encoding putative tran scriptional regulators. While PCR primers derived from transcriptional regulator gene la1137 recognized all 24 pathogenic Leptospira strains representing seven species, those from la1937, la3231, la3825, and la4130 detected 19 of the 24 Leptospira strains. However, none of these primers reacted with four nonpathogenic Leptospira species or other common bacteria. The putative transcriptional regulator genes la1137, la1937, la3231, la3825, and la4130 are present in pathogenic Leptospira strains, making them potential targets for diagnostic applications. Further characterization of these genes and their proteins may help elucidate the molecular mechanisms of leptospiral virulence and pathogenicity and pave the way for potential development of novel control strategies against leptospirosis.Key words: Leptospira, pathogenic, transcriptional regulator gene, PCR, identification.
33
Poonacha, K. B., J. M. Donahue, R. C. Giles, C. B. Hong, M. B. Petrites-Murphy, B. J. Smith, T. W. Swerczek, R. R. Tramontin e P. A. Tuttle. "Leptospirosis in Equine Fetuses, Stillborn Foals, and Placentas". Veterinary Pathology 30, n. 4 (luglio 1993): 362–69. http://dx.doi.org/10.1177/030098589303000405.
Testo completoAbstract (sommario):
Leptospirosis was diagnosed in 51 equine fetuses and 16 stillborn foals with gestational ages from 3½ to 11 months. Diagnosis was based on one or more of the following: positive fetal antibody titer, positive fluorescent antibody test, demonstration of spirochetes in kidney and/or placental sections stained by the Warthin-Starry technique, high leptospiral titers in aborting mares, or isolation of Leptospira spp. from fetal organs. Gross lesions were observed in 80.3% of the fetuses, stillborn foals, and placentas. Gross placental lesions included nodular cystic allantoic masses, edema, areas of necrosis of the chorion, and necrotic mucoid exudate coating the chorion. The liver (23 cases) was enlarged, mottled, and pale to yellow. The kidneys (seven cases) were swollen and edematous with pale white radiating streaks in cortex and medulla. Microscopic lesions were observed in 96% of fetuses, stillborn foals, and placentas. Placental lesions consisted of thrombosis, vasculitis, mixed inflammatory cell infiltration of the stroma and villi, cystic adenomatous hyperplasia of allantoic epithelium, and villous necrosis and calcification. Fetal lesions included hepatocellular dissociation, mixed leukocytic infiltration of the portal triads, giant cell hepatopathy, suppurative and nonsuppurative nephritis, pulmonary hemorrhages, pneumonia, and myocarditis. Spirochetes were demonstrated with the Warthin-Starry stain in the allantochorion and/or kidney of 69 of the 71 cases. Using the direct fluorescent antibody technique, 56/60 cases tested positively for leptospires. Leptospires were isolated from fetal tissues in 20/42 cases. Sixteen of the isolates were identified by restriction enzyme analysis as Leptospira interrogans serogroup Pomona serovar kennewicki; case Nos. 36 and 41 were serovar grippotyphosa. The other two isolates were not identified. Microagglutination titers against leptospires were demonstrated in the body fluid of 47/67 cases tested and titers ranged from 1:50 to greater than 1:1,638,400 against Leptospira interrogans serovars pomona, grippotyphosa, copenhageni, hardjo, canicola, and bratislava. Sixty-two of 71 aborting mares tested had titers ranging from 200 to greater than 3,276,800. Leptospiral antibody titers in the body fluid and gross and histopathologic lesions did not differ with age, breed, or sex or between fetuses and stillborn foals.
34
Bertasio, Cristina, Maria Beatrice Boniotti, Laura Lucchese, Letizia Ceglie, Laura Bellinati, Matteo Mazzucato, Tommaso Furlanello, Mario D’Incau e Alda Natale. "Detection of New Leptospira Genotypes Infecting Symptomatic Dogs: Is a New Vaccine Formulation Needed?" Pathogens 9, n. 6 (18 giugno 2020): 484. http://dx.doi.org/10.3390/pathogens9060484.
Testo completoAbstract (sommario):
Leptospirosis in dogs has been largely described worldwide, and epidemiological studies have been mainly based on serological data. This study aims to detect and genotype leptospires affecting symptomatic dogs in Northeast Italy between 2013 and 2019. Overall, 1631 dogs were tested using real-time PCR, and leptospires from 193 dogs were subjected to Multilocus Sequence Typing and a Multiple Loci Variable-number Tandem Repeat Analysis. Leptospires were successfully isolated from 15 symptomatic dogs. Six distinct Sequence Types (STs) were found for 135 leptospires, with 3 STs characterizing Leptospira interrogans (ST17, ST198 and ST24), 2 STs characterizing Leptospira kirschneri (ST117 and ST289) and 1 ST characterizing Leptospira borgpetersenii (ST155), revealing the circulation of the serogroups Icterohaemorrhagiae, Australis, Sejroe and Pomona. The Multiple Loci Variable-number Tandem Repeat Analysis of 17 samples did not result in any additional discrimination. Genotypes were compared with those of strains present in the historical internal database, and possible transmission chains were identified from rat, mouse, hedgehog and pig. This work highlights the importance of molecular methods in revealing and identifying circulating Leptospira strains, and it also encourages the evaluation of the ability of commercially available vaccines to reduce the disease burden among dogs.
35
BEDIR, ORHAN, ABDULLAH KILIC, ERDINC ATABEK, AHMET MERT KUSKUCU, VEDAT TURHAN e A. CELAL BASUSTAOGLU. "Simultaneous Detection and Differentiation of Pathogenic and Nonpathogenic Leptospira spp. by Multiplex Real-Time PCR (TaqMan) Assay". Polish Journal of Microbiology 59, n. 3 (2010): 167–73. http://dx.doi.org/10.33073/pjm-2010-026.
Testo completoAbstract (sommario):
Leptospirosis, caused by pathogenic Leptospira, is one of the most important zoonoses in the world. Several molecular techniques have been developed for detection and differentiation between pathogenic and saprophytic Leptospira spp. The aim of this study was to develop a rapid and simple assay for specific detection and differentiation of pathogenic Leptospira spp. by multiplex real-time PCR (TaqMan) assay using primers and probes targeting Leptospira genus specific 16S ribosomal RNA gene, the pathogen specific lig A/B genes and nonpathogen Leptospira biflexa specific 23S ribosomal RNA gene. Sixteen reference strains of Leptospira spp. including pathogenic and nonpathogenic and ten other negative control bacterial strains were used in the study. While the 16S primers amplified target from both pathogenic and non-pathogenic leptospires, the ligA/B and the 23S primers amplified target DNA from pathogenic and non-pathogenic leptospires, respectively. The multiplex real-time PCR (TaqMan) assay detection limit, that is, the sensitivity was found approximately 1 x 10(2) cells/ml for ligA/B gene and 23S ribosomal RNA gene, and 10 cells/ml 16S ribosomal RNA. The reaction efficiencies were 83-105% with decision coefficients of more than 0.99 in all multiplex assays. The multiplex real-time PCR (TaqMan) assay yielded negative results with the ten other control bacteria. In conclusion, the developed multiplex real-time PCR (TaqMan) assay is highly useful for early diagnosis and differentiation between pathogenic and non-pathogenic leptospires in a reaction tube as having high sensitivity and specificity.
36
ADLER, H., S. VONSTEIN, P. DEPLAZES, C. STIEGER e R. FREI. "Prevalence of Leptospira spp. in various species of small mammals caught in an inner-city area in Switzerland". Epidemiology and Infection 128, n. 1 (febbraio 2002): 107–9. http://dx.doi.org/10.1017/s0950268801006380.
Testo completoAbstract (sommario):
In order to establish the leptospira carrier rate of small animals in an urban environment, small rodents and shrews were captured in the city of Zurich, Switzerland. Kidney specimens of 190 animals were examined using a leptospira specific PCR assay. Leptospiral DNA was amplified in kidneys of 12·6% of the animals.
37
Safiee, Amira Wahida Mohamad, Mohammad Ridhuan Mohd Ali, Muhammad Zarul Hanifah Md Zoqratt, Tan Hock Siew, Chua Wei Chuan, Lee Lih Huey, Mohd Hashairi Fauzi, Alwi Muhd Besari, Chan Yean Yean e Nabilah Ismail. "Putative Pathogenic Genes of Leptospira interrogans and Leptospira weilii Isolated from Patients with Acute Febrile Illness". Tropical Medicine and Infectious Disease 7, n. 10 (5 ottobre 2022): 284. http://dx.doi.org/10.3390/tropicalmed7100284.
Testo completoAbstract (sommario):
Leptospirosis is an important worldwide tropical disease caused by pathogenic Leptospira spp. The determination of virulence genes is important, as it influences patients’ clinical manifestations and clinical outcomes. This case report focused on detecting the pathogenic genes of Leptospira in association with the clinical manifestations of patients at the Hospital Universiti Sains Malaysia, Malaysia, who presented with acute febrile illness. Two cases were found and, to the best of our knowledge, these were the first two cases in Malaysia in which patients presented with febrile illness were associated with successful Leptospira isolation from clinical samples. Both clinical isolates were identified by 16S rRNA sequencing as Leptospira weilii and Leptospira interrogans, respectively, and they were classified as pathogenic Leptospira by the presence of different pathogenic genes, based on a polymerase chain reaction (PCR) amplification of targeted genes. This report emphasizes that different infecting Leptospira species and the presence of different virulence factors cause a slight difference in clinical manifestations and laboratory findings of leptospirosis. Genomic sequencing and annotation revealed the detection of classical leptospiral virulence factor genes that were otherwise missed using PCR for detection of Leptospira weilii genome B208.
38
Román-Cárdenas, Franklin, Franco Cordero Salazar, Amdrés Mora e Pablo Ramón. "SEROPREVALENCIA A LEPTOSPIRA SPP., Y NEOSPORA CANINUM EN GANADERÍAS DEL CANTÓN LOJA." Perfiles 1, n. 28 (1 agosto 2022): 52–58. http://dx.doi.org/10.47187/perf.v1i28.182.
Testo completoAbstract (sommario):
Leptospirosis y neosporosis son enfermedades abortivas en el ganado bovino, la primera, una zoonosis producida por leptospiras, la segunda por un protozoario Neospora caninum enfermedad emergente en perros. Los objetivos fueron determinar la seroprevalencia de los bovinos a Neospora caninum y leptospira spp. Se utilizaron muestras de suero bovino, la determinación de anticuerpos a Neospora caninum mediante cELISA y de leptospira spp., por MAT, para la confirmación de ooquistes de Neospora caninum se realizó el examen coprológico Teleman, en el caso de seroreactores a leptospira spp., se obtuvo una segunda muestra, se analizaron 956 muestras de 158 UPAs, el 19.35 % resultaron seroprevalentes a Neospora caninun, a leptospira spp., una seroprevalencia del 74,83% , con títulos de 1/400 a la primera muestra del 28% y con títulos de 1/800 el 0.2%, la muestra pareada arrojo títulos de 1/400 en el 28% de las muestras, a las dos enfermedades una seroprevalencia de 19.17%, en los alrededores de la parroquia San Sebastián, existe mayor probabilidad de identificar leptospiras y en Jimbilla neosporas.
39
Levett, P. N., R. E. Morey, R. Galloway, A. G. Steigerwalt e W. A. Ellis. "Reclassification of Leptospira parva Hovind-Hougen et al. 1982 as Turneriella parva gen. nov., comb. nov." International Journal of Systematic and Evolutionary Microbiology 55, n. 4 (1 luglio 2005): 1497–99. http://dx.doi.org/10.1099/ijs.0.63088-0.
Testo completoAbstract (sommario):
Analysis of the G+C content, DNA–DNA relatedness to other leptospires and 16S rRNA gene sequence of Leptospira parva showed that this species was not related to other Leptospira species. On the basis of these data, it is proposed that Leptospira parva should be transferred to the genus Turneriella as Turneriella parva gen. nov., comb. nov., with strain HT (=NCTC 11395T=ATCC BAA-1111T) as the type strain.
40
Azali, Muhammad Azharuddin, Chan Yean Yean, Azian Harun, Nurul Najian Aminuddin Baki e Nabilah Ismail. "Molecular Characterization ofLeptospiraspp. in Environmental Samples from North-Eastern Malaysia Revealed a Pathogenic Strain,Leptospira alstonii". Journal of Tropical Medicine 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/2060241.
Testo completoAbstract (sommario):
The presence of pathogenicLeptospiraspp. in the environment poses threats to human health. The aim of this study was to detect and characterizeLeptospiraspp. from environmental samples. A total of 144 samples comprised of 72 soil and 72 water samples were collected from markets and recreational areas in a north-eastern state in Malaysia. Samples were cultured on Ellinghausen and McCullough modified by Johnson and Harris media. Leptospires were positive in 22.9% (n=33) of the isolates. Based on partial sequences of 16S rRNA, a pathogenic leptospire,Leptospira alstonii(n=1/33), was identified in 3% of the isolates followed by intermediate leptospire (L. wolffii,n=1/33, andL. licerasiae,n=7/33) and nonpathogenic leptospire,L. meyeri(n=22/33) in 24.2% and 66.7%, respectively. This study demonstrates the presence of a clinically significant pathogenicL. alstoniiin the environments which could pose health risks to the occupants and visitors.
41
Balboni, Andrea, Elisa Mazzotta, Maria Beatrice Boniotti, Cristina Bertasio, Laura Bellinati, Laura Lucchese, Mara Battilani et al. "Outbreak of Leptospira borgpetersenii Serogroup Sejroe Infection in Kennel: The Role of Dogs as Sentinel in Specific Environments". International Journal of Environmental Research and Public Health 19, n. 7 (25 marzo 2022): 3906. http://dx.doi.org/10.3390/ijerph19073906.
Testo completoAbstract (sommario):
Kennels may represent high-risk environments for the diffusion of Leptospira infection in dogs and consequently a threat to public health. This study describes an outbreak of Leptospira infection in a kennel in Italy in 2020, both with clinically ill and asymptomatic dogs. Fifty-nine dogs, including three ill dogs, were tested for Leptospira spp. infection by the microscopic agglutination test (MAT) and real-time qPCR. Multi-locus sequence typing (MLST) analysis was used to genotype the identified leptospires. Thirty of the fifty-nine (50.9%) dogs had MAT titer and/or molecular positivity indicative of Leptospira infection. Twenty-two of the fifty-nine (37.3%) dogs exhibited seropositivity against at least one serovar belonging to the Sejroe serogroup, and MLST analysis identified L. borgpetersenii serogroup Sejroe (Leptospira ST155) as responsible for the outbreak. Up to now, Sejroe serogroup infection was sporadically reported in dogs. The extension of the MAT antigen panel to several serovars belonging to the serogroup Sejroe could be useful in the diagnosis of canine leptospirosis. Dogs may serve as sentinel of leptospires in specific environments, and surveillance of Leptospira infection in kennels is strongly recommended even when the correct vaccine prophylaxis is administered, because the vaccines currently available are not able to protect from all of the serogroups.
42
Melo, Tuane Ferreira, e Ana Paula Peconick. "As características da Leptospira spp.: uma revisão de literatura". Scire Salutis 9, n. 3 (5 novembre 2019): 1–7. http://dx.doi.org/10.6008/cbpc2236-9600.2019.003.0001.
Testo completoAbstract (sommario):
A leptospirose é uma doença zoonótica com distribuição mundial que acomete animais domésticos e silvestres e humanos. Devido às altas taxas de mortalidade e morbidade é importante conhecer as características da Leptospira spp. para estabelecer medidas para o controle e prevenção. A Leptospira spp. são bactérias gram-negativas com formato de espiroquetas e possuem espécies saprófitas e patogênicas. As espécies patogênicas mais frequentemente associadas a casos graves humanos no Brasil são a Leptospira Icterohaemorrhagiae e a Leptospira Copenhagueni. A compreensão da interação das leptospiras com o meio ambiente e com seus hospedeiros, desencadeando a doença permite estabelecer um tratamento eficaz dos animais e humanos acometidos e também atuar rapidamente no controle e prevenção da leptospirose.
43
Manglicmot-Yabes, Ailyn, Sharon Yvette Angelina Villanueva e Nina Gloriani. "Optimized Tube Dilution Technique and Sole Carbon Utilization Assay for Anti-leptospiral In Vitro Screening of Plant Extracts". Pediatric Infectious Disease Society of the Philippines Journal 21, n. 2 (1 dicembre 2020): 3–12. http://dx.doi.org/10.56964/pidspj20202102002.
Testo completoAbstract (sommario):
Introduction: Leptospirosis is one of the neglected reemerging zoonoses that is of public health concern globally. The need to discover novel therapeutic alternatives for leptospirosis through screening for and elucidating the mechanism/s of the anti-leptospiral activity of plant extracts is therefore necessary. This study analyzes the optimized tube dilution technique and the BiologTM sole carbon utilization phenotype microarray as screening tool for anti-leptospiral activity of plant extracts. Methods: The suitability of the optimized tube dilution technique was evaluated by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and motility inhibition property of a plant extract and an antimicrobial control (pen G) against 4 dominantly circulating Leptospira serovars/serogroup in the Philippines. Likewise, the suitability of the BiologTM sole carbon utilization assay was evaluated using a plant extract and selected antimicrobials against L. interrogans serovar Manilae strain K64 and L. interrogans serovar Losbanos strain K37. Results: The MIC, MBC, and motility inhibition property of a plant extract and the antibiotic controls as well as its effect on the carbon utilization phenome of the Leptospira serovars gave consistent results, within and between several runs. With standard deviation = 0 for all serovars. The MIC and MBC of the antimicrobial control (pen G), the positive control, was 10 ug/ml. The growth control (leptospires without treatment), the negative control, showed presence of motile leptospires. The MIC and the MBC of the test plant extract was 250 ug/ml – 500 ug/ml. Results of the carbon utilization phenome or pattern of carbon utilization were consistent within the 3 replicates and between two runs. Conclusion: The optimized tube dilution technique and the BiologTM sole carbon utilization assay is a potential in vitro screening tool for determining anti-leptospiral activity of plant extracts.
44
Piredda, Ivana, Sara Sechi, Raffaella Cocco, Loris Bertoldi, Bruna Palmas e Valentina Chisu. "Isolation of Leptospira interrogans Serovar Canicola in a Vaccinated Dog without Clinical Symptoms". Pathogens 11, n. 4 (27 marzo 2022): 406. http://dx.doi.org/10.3390/pathogens11040406.
Testo completoAbstract (sommario):
More than one million cases of leptospirosis occur across the globe annually, resulting in about 59,000 deaths. Dogs are one of the most important reservoirs of Leptospira species and play an important role in transmitting the pathogen to humans. Many of these infections are controlled by routine vaccination that has reduced the possible reintroduction of leptospiral serovars into the human population. However, it is still not clear how a vaccinated dog can become infected with one or more Leptospira serovars contained in the vaccine formulation and thus against which it should be immunized. Here, we present the case of an asymptomatic dog who developed leptospiral infection despite being vaccinated. This unusual case emphasizes the substantial impact of immunization on mitigating the acute signs of the disease, even while providing limited protection against infection. Further studies will be required to better understand the role of dogs in the environmental circulation of leptospiral serovars in Sardinia. Asymptomatic leptospiral infection in vaccinated dogs should be considered to allow for better diagnosis and management of the infection. This will be essential for preventing Leptospira outbreaks in the future.
45
Director, A., B. Penna, C. Hamond, A. P. Loureiro, G. Martins, M. A. Medeiros e W. Lilenbaum. "Isolation of Leptospira interrogans Hardjoprajitno from vaginal fluid of a clinically healthy ewe suggests potential for venereal transmission". Journal of Medical Microbiology 63, n. 9 (1 settembre 2014): 1234–36. http://dx.doi.org/10.1099/jmm.0.065466-0.
Testo completoAbstract (sommario):
A total of 15 adult ewes from one flock known to be seroreactive for leptospirosis was studied. Urine and vaginal fluid were collected from each animal to test for the presence of leptospires using bacterial culture and conventional PCR methods. One pure culture of Leptospira sp. was obtained from the vaginal fluid sample of a non-pregnant ewe. The isolate was characterized by DNA sequencing of the rrs and secY genes, variable-number of tandem-repeats (VNTR) analysis and serogrouping, and the isolate was typed as Leptospira interrogans serogroup Sejroe serovar Hardjo type Hardjoprajitno. This report indicates the presence of viable Leptospira in the vaginal fluid of a ewe, suggesting the potential for venereal transmission of leptospires in sheep.
46
Silva, Éverton F., Núbia Seyffert, Sandra D. D. Jouglard, Daniel A. Athanazio, Odir A. Dellagostin e Claudiomar S. Brod. "Soroprevalência da infecção leptospiral em capivaras (Hydrochoerus hydrochaeris) abatidas em um frigorífico do Rio Grande do Sul". Pesquisa Veterinária Brasileira 29, n. 2 (febbraio 2009): 174–76. http://dx.doi.org/10.1590/s0100-736x2009000200016.
Testo completoAbstract (sommario):
Capivaras (Hydrochoerus hydrochaeris) são roedores selvagens do continente americano com crescente importância comercial como fonte alternativa de carne para o consumo humano. Nessa espécie, os estudos sobre a soroprevalência da infecção leptospiral são escassos e restritos aos espécimes de vida livre. Relatamos aqui reações positivas para anticorpos aglutinantes anti-leptospiras em 27,3% (6/22) das capivaras abatidas em um frigorífico do Rio Grande do Sul. Os níveis mais altos de anticorpos sugerem infecção pelo sorogrupo Australis devido à reação para uma cepa de referência do sorovar Bratislava e para um isolado canino local do sorovar Australis, caracterizado como Leptospira noguchii. Esses resultados ressaltam que considerável parcela de capivaras criadas em cativeiro podem funcionar como reservatório de leptospiras patogênicas e chamam atenção para o risco ocupacional dos trabalhos que envolvem a criação e o abate dessa espécie animal.
47
Macaluso, Giusi, Alessandra Torina, Valeria Blanda, Annalisa Guercio, Antonio Lastra, Ilenia Giacchino, Rosalia D’Agostino et al. "Leptospira in Slaughtered Fattening Pigs in Southern Italy: Serological Survey and Molecular Typing". Animals 12, n. 5 (25 febbraio 2022): 585. http://dx.doi.org/10.3390/ani12050585.
Testo completoAbstract (sommario):
Leptospirosis is a re-emerging zoonosis of worldwide significance; a wide spectrum of wild and domestic animal species act as natural or accidental hosts. Swine can act as maintenance or accidental hosts of pathogenic Leptospira spp. This study aimed at investigation of Leptospira spp. prevalence and diversity in slaughtered pigs in southern Italy (Sicily). In total, 55 samples of kidneys and blood were collected. Microscopic agglutination test and real-time PCR were performed to detect pathogenic and intermediately pathogenic Leptospira. Partial rpoB gene sequencing and multi-locus sequence typing (MLST) were performed to characterize Leptospira species. The analysis showed a seropositivity rate of 16.4%, with Australis representing the most frequently identified serogroup (63.64%); Pomona and Sejroe were detected with a prevalence of 27.27% and 9.09%, respectively. Pathogenic Leptospiral DNA was detected in 2 kidney samples (3.64%). Leptospira were identified through MLST as L. borgpetersenii serovar Tarassovi (serogroup Tarassovi). Obtained data confirmed the presence of Leptospira infection among pigs in southern Italy, suggesting that management of these animals may be considered an occupational risk for humans.
48
Villanueva, Sharon Y. A. M., Mitsumasa Saito, Yutaka Tsutsumi, Takaya Segawa, Rubelia A. Baterna, Antara Chakraborty, Tatsuma Asoh et al. "High virulence in hamsters of four dominant Leptospira serovars isolated from rats in the Philippines". Microbiology 160, n. 2 (1 febbraio 2014): 418–28. http://dx.doi.org/10.1099/mic.0.072439-0.
Testo completoAbstract (sommario):
Leptospirosis is caused by pathogenic species of Leptospira. The aim of this study was to determine and characterize the pathogenicity of four dominant Leptospira isolates prevailing among rats in the Philippines. The isolates were Leptospira interrogans serovar Manilae strain K64, L. interrogans serovar Losbanos strain K37, L. interrogans serovar Ratnapura strain K5 and Leptospira borgpetersenii serovar Javanica strain K6. Pathogenicities were studied using hamsters, which reproduce severe human leptospirosis. The minimum lethal doses were 100 ( = 1) leptospires for K64, K37 and K5, and 101 leptospires for K6. Weight loss amongst the Leptospira-infected hamsters was observed from 1 day before death (K64-, K37- and K5-infected hamsters) to as much as 1 week before death for K6-infected hamsters. Similar and varied gross and microscopic lesions were observed amongst infected hamsters, even for strains belonging to the same species (i.e. L. interrogans). The most significant and common histopathological findings were congestion of the glomerulus, disarrangement of hepatic cords and erythrophagocytosis. Other findings were foamy splenic macrophages for K6, severe petechial pulmonary haemorrhage for K64, and hematuria and severe pulmonary congestion for K37. Immunostaining and culture revealed the presence of leptospires in different organs of the infected hamsters. Based on these results, Leptospira isolates from rats in the Philippines were shown to be highly virulent, causing pulmonary haemorrhage, severe hepato-renal damage and death in hamsters even at lower doses. The present findings on experimental leptospirosis support clinical data showing that patients with severe manifestations of leptospirosis, such as pulmonary haemorrhage, are increasing in the Philippines. These findings may serve as a basis to strengthen the early diagnosis and treatment of human leptospirosis.
49
Nepeřený, Jiří, Josef Chumela e Vladimír Vrzal. "Determination of an infectious dose of Leptospira for the performance of challenge test in assessing the efficacy of Leptospira vaccines". Acta Veterinaria Brno 80, n. 3 (2011): 263–68. http://dx.doi.org/10.2754/avb201180030263.
Testo completoAbstract (sommario):
The efficacy of vaccines against leptospiral disease can be determined objectively by challenge test in experimental animals. Selection of suitable leptospiral challenge strains and determination of an optimal challenge dose to prove exactly that the given vaccine Leptospira serotype induces protective immunity in vaccinated dogs is a critical point in performing challenge experiments. The aim of our study was to verify and determine an appropriate challenge dose for efficacy tests in dogs for the following Leptospira serovars: L. grippotyphosa, L. icterohaemorrhagiae and L. canicola. The appropriate challenge dose was determined on the basis of pathognomonic symptoms of infection, Leptospira capture at cultivation and pathological changes in dogs infected experimentally with various doses (5 × 104 - 5 × 108) of Leptospira serovars. A dose of 5 × 106 of each respective serovar administered intraperitoneally was determined to be a suitable challenge dose. The dogs infected with the selected dose showed the typical symptoms of the disease and met the requirements of an objective and standard evaluation of the vaccine efficacy according to the pharmacopoeial monograph. A study of such extent was done for the first time in the Czech Republic.
50
Faber, Nick A., Melissa Crawford, Rance B. LeFebvre, Nedim C. Buyukmihci, John E. Madigan e Neil H. Willits. "Detection of Leptospira spp. in the Aqueous Humor of Horses with Naturally Acquired Recurrent Uveitis". Journal of Clinical Microbiology 38, n. 7 (2000): 2731–33. http://dx.doi.org/10.1128/jcm.38.7.2731-2733.2000.
Testo completoAbstract (sommario):
Leptospiral organisms have long been presumed to be associated with the presence of equine recurrent uveitis. This project was undertaken to determine the presence of Leptospira spp. in the aqueous humor of horses with uveitis to determine if there was an association with inflammation. Thirty horses were determined to have recurrent uveitis based on clinical evaluation or history. Sixteen horses were judged clinically and historically to be free of uveitis and were used as controls. Aqueous humor samples were cultured and evaluated by PCR for the presence of Leptospira DNA. Serum was collected and evaluated for the presence of antibodies against five serovars in a leptospirosis panel. Twenty-one of 30 horses with recurrent uveitis and one of 16 uveitis-free horses were positive by PCR for the presence ofLeptospira DNA. Six of these 21 horses with uveitis were culture positive for leptospires from the aqueous humor. Serologic results did not correlate well with the presence ofLeptospira DNA or organisms in the aqueous humor.Leptospira spp. are present in a high percentage of horses with naturally occurring recurrent uveitis.