Hedgehogs and Mustelid Species: Major Carriers of Pathogenic Leptospira, a Survey in 28 Animal Species in France (20122015)

Tracking potential Leptospira sources following human cases of leptospirosis: A One Health approach applied to an ecosystem in Brittany, France

Pathogenic Leptospira can cause leptospirosis: a widespread, potentially fatal bacterial zoonosis whose risk is mediated by the soil and water features, animal host distributions, meaning the local ecosystem. When human cases of leptospirosis occur, it is challenging to track down their source because ecosystem-level epidemiological knowledge on Leptospira is needed. Between 2016 and 2019 in a focal riparian ecosystem, the human population experienced an outbreak and successive cases of leptospirosis attributable to L. kirschneri and L. interrogans. The epidemiological investigation was carried out using the One Health approach, as described in international health guidelines. As a first step in this process, we investigated leptospiral carriage in the main animal hosts found in the region. We sampled 143 nutrias, 17 muskrats, and 10 Norway rats using convenient trapping. DNA was extracted from their kidneys, lungs, and urine and subjected to real-time PCR (RT-PCR) targeting the Leptospira 16S rDNA and lfb1 genes. In the farms along the river's stretch of interest, we sampled serum from 439 cattle and used a microscopic agglutination test to detect the presence of antibodies against Leptospira. Urine samples were concomitantly obtained from 145 cattle and were used in two analyses: RT-PCR targeting the Leptospira 16S rDNA gene and Leptospira culturing. We found th, wt rodents were the most likely source of the L. interrogans behind the human cases. The cattle tested negative for Leptospira DNA but positive for antibodies against the serogroups implicated in the human cases. We failed to identify the potential source of the L. kirschneri responsible for several human cases of leptospirosis. Our results call for further clarification of the Leptospira maintenance community, which may comprise known maintenance hosts, such as rodents, as well as taxa not commonly considered to be maintenance hosts but that can still spread Leptospira. The resulting research network will collaboratively conduct future eco-epidemiological surveys to illuminate the leptospirosis risks faced by humans and animals within ecosystems.

Prevalence, genetic diversity and eco-epidemiology of pathogenic Leptospira species in small mammal communities in urban parks Lyon city, France

Rodents are recognized as the main reservoirs of Leptospira spp. Rats, in particular, serve as hosts for the widely predominant Leptospira interrogans serovar Icterohaemorrhagiae, found worldwide. Several studies have shown the importance of other reservoirs, such as mice or hedgehogs, which harbor other leptospires' serovars. Nevertheless, our knowledge of circulating Leptospira spp. in reservoirs other than rats remains limited. In this context, we proposed an eco-health approach to assess the health hazard associated with leptospires in urban green spaces, where contacts between human/small mammals and domestic animals are likely. We studied the prevalence, the diversity of circulating strains, and epidemiology of pathogenic Leptospira species in small terrestrial mammal communities (rodents and shrews), between 2020-2022, in two parks in Lyon metropolis, France. Our study showed a significant carriage of Leptospira spp. in small terrestrial mammals in these parks and unveiled a global prevalence rate of 11.4%. Significant variations of prevalence were observed among the small mammal species (from 0 to 26.1%), with Rattus norvegicus exhibiting the highest infection levels (26.1%). We also observed strong spatio-temporal variations in Leptospira spp. circulation in its reservoirs. Prevalence seems to be higher in the peri-urban park and in autumn in 2021 and 2022. This is potentially due to differences in landscape, abiotic conditions and small mammal communities' composition. Our study suggests an important public health relevance of rats and in a lesser extent of other rodents (Apodemus spp., Clethrionomys glareolus and Mus musculus) as reservoirs of L. interrogans, with rodent species carrying specific serogroups/serovars. We also emphasize the potential hazard associated between the shrew Crocidura russula and L. kirschneri. Altogether, these results improve our knowledge about the prevalence of leptospirosis in an urban environment, which is an essential prerequisite for the implementation of prevention of associated risks.

Molecular typing of Leptospira spp. in farmed and wild mammals reveals new host-serovar associations in New Zealand

AIMS

To apply molecular typing to DNA isolated from historical samples to determine Leptospira spp. infecting farmed and wild mammals in New Zealand.

MATERIALS AND METHODS

DNA samples used in this study were extracted from urine, serum or kidney samples (or Leptospira spp. cultures isolated from them) collected between 2007 and 2017 from a range of domestic and wildlife mammalian species as part of different research projects at Massey University. Samples were included in the study if they met one of three criteria: samples that tested positive with a lipL32 PCR for pathogenic Leptospira; samples that tested negative by lipL32 PCR but were recorded as positive to PCR for pathogenic Leptospira in the previous studies; or samples that were PCR-negative in all studies but were from animals with positive agglutination titres against serogroup Tarassovi. DNA samples were typed using PCR that targeted either the glmU or gyrB genetic loci. The resulting amplicons were sequenced and typed relative to reference sequences.

RESULTS

We identified several associations between mammalian hosts and Leptospira strains/serovars that had not been previously reported in New Zealand. Leptospira borgpetersenii strain Pacifica was found in farmed red deer (Cervus elaphus) samples, L. borgpetersenii serovars Balcanica and Ballum were found in wild red deer samples, Leptospira interrogans serovar Copenhageni was found in stoats (Mustela erminea) and brushtail possums (Trichosurus vulpecula), and L. borgpetersenii was found in a ferret (Mustela putorius furo). Furthermore, we reconfirmed previously described associations including dairy cattle with L. interrogans serovars Copenhageni and Pomona and L. borgpetersenii serovars Ballum, Hardjo type bovis and strain Pacifica, sheep with L. interrogans serovar Pomona and L. borgpetersenii serovar Hardjo type bovis, brushtail possum with L. borgpetersenii serovar Balcanica, farmed deer with L. borgpetersenii serovar Hardjo type bovis and hedgehogs (Erinaceus europaeus) with L. borgpetersenii serovar Ballum.

CONCLUSIONS

This study provides an updated summary of host-Leptospira associations in New Zealand and highlights the importance of molecular typing. Furthermore, strain Pacifica, which was first identified as Tarassovi using serological methods in dairy cattle in 2016, has circulated in animal communities since at least 2007 but remained undetected as serology is unable to distinguish the different genotypes.

CLINICAL RELEVANCE

To date, leptospirosis in New Zealand has been diagnosed with serological typing, which is deficient in typing all strains in circulation. Molecular methods are necessary to accurately type strains of Leptospira spp. infecting mammals in New Zealand.

Identification of zoonotic pathogenic bacteria from blood and ticks obtained from hares and long-eared hedgehogs (Hemiechinus megalofis) in eastern Iran

The role of wildlife in the complex balance of tick-borne diseases within ecosystems is crucial, as they serve as hosts for tick carriers and reservoirs for the pathogens carried by these ticks. This study aimed to investigate the presence of zoonotic pathogenic bacteria in wildlife, specifically in hares and long-eared hedgehogs (Hemiechinus megalofis), in the eastern region of Iran. The focus was on the detection of Borrelia spp., Coxiella burnetii, Anaplasma spp., Francisella spp., and Leptospira spp., using the Nested-PCR method. We analyzed a total of 124 blood samples, and 196 ticks collected from hares and long-eared hedgehogs were analyzed. The Nested-PCR method was employed to identify the presence of zoonotic pathogenic bacteria DNA. Our study revealed the presence of these zoonotic pathogenic bacteria in both wildlife species, indicating their potential role as hosts and reservoirs for the ticks carrying these pathogens. The specific presence and prevalence of Borrelia spp., Coxiella burnetii, Anaplasma spp., Francisella spp., and Leptospira spp. were determined through the Nested-PCR method. This study contributes to the limited knowledge about the involvement of wild animals in the transmission of tick-borne diseases. By using the Nested-PCR method, we successfully identified the presence of zoonotic pathogenic bacteria in hares and long-eared hedgehogs. This study emphasizes the need for further research to better understand the ecological process of tick-borne diseases, particularly the role of wildlife in their spread. Such knowledge is crucial for wildlife conservation efforts and the management of tick-borne diseases, ultimately benefiting both animal and human health.

Assessment of virus and Leptospira carriage in bats in France

With over 1,400 species worldwide, bats represent the second largest order of mammals after rodents, and are known to host major zoonotic pathogens. Here, we estimate the presence of pathogens in autochthonous bat populations. First, we set out to check our samples for PCR amplification efficiency by assessing the occurrence of inhibited PCR reactions from different types of bat samples with amplifying the housekeeping gene β-actin. Second, we investigated the presence of five targeted pathogens in a French bat population using PCR. We targeted viral RNA of Canine distemper virus, Alphacoronavirus, Lyssavirus, Rotavirus and bacterial Leptospira DNA. To do so, we screened for these viruses in bat faecal samples as well as in oropharyngeal swab samples. The presence of Leptospira was assessed in urine, kidney, lung and faecal samples. Results showed a frequency of inhibited reactions ranging from 5 to 60% of samples, varying according to the sample itself and also suspected to vary according to sampling method and the storage buffer solution used, demonstrating the importance of the sampling and storage on the probability of obtaining negative PCR results. For pathogen assessment, rotavirus and alphacoronavirus RNA were detected in Myotis myotis, Myotis daubentonii, Myotis emarginatus and Rhinolophus ferrumequinum bats. Rotaviruses were also detected in Barbastella barbastellus. The presence of alphacoronavirus also varied seasonally, with higher frequencies in late summer and October, suggesting that juveniles potentially play an important role in the dynamics of these viruses. Leptospira DNA was detected in M. myotis and M. daubentonii colonies. The 16S rRNA sequences obtained from Leptospira positive samples showed 100% genetic identity with L. borgpetersenii. Neither canine distemper virus nor lyssavirus RNA were detected in any of the tested samples. This study is the first to show the presence of Leptospira in autochthonous French bats in addition to coronavirus and rotavirus RNA previously reported in European autochthonous bats.

Genetic diversity of Leptospira strains circulating in humans and dogs in France in 2019-2021

Leptospirosis is a bacterial zoonotic disease. Humans and dogs are susceptible hosts, with similar clinical manifestations ranging from a febrile phase to multiple organ dysfunction. The incidence of leptospirosis in mainland France is relatively high, at about 1 case per 100,000 inhabitants, but our knowledge of the strains circulating in humans and dogs remains limited. We studied the polymorphism of the lfb1 gene sequences in an exhaustive database, to facilitate the identification of Leptospira strains. We identified 46 species-groups (SG) encompassing the eight pathogenic species of Leptospira. We sequenced the lfb1 gene amplification products from 170 biological samples collected from 2019 to 2021: 110 from humans and 60 from dogs. Epidemiological data, including vaccination status in dogs, were also collected. Three Leptospira species displaying considerable diversity were identified: L. interrogans, with eight lfb1 species-groups (including five new lfb1 species-groups) in humans and dogs; L. kirschneri, with two lfb1 species-groups in humans and dogs; and L. borgpetersenii, with one lfb1 species-group in humans only. The lfb1 species-group L. interrogans SG1, corresponding to serovar Icterohaemorrhagiae or Copenhageni, was frequently retrieved from both humans and dogs (n=67/110; 60.9% and n=59/60; 98.3% respectively). A high proportion of the affected dogs developed the disease despite vaccination (n=30/60; 50%). Genotyping with the polymorphic lfb1 gene is both robust and simple. This approach provided the first global picture of the Leptospira strains responsible for acute infections in mainland France, based on biological samples but without the need for culture. Identification of the Leptospira strains circulating and their changes over time will facilitate more precise epidemiological monitoring of susceptible and reservoir species. It should also facilitate the monitoring of environmental contamination, making it possible to implement preventive measures and to reduce the burden of this disease.

Spatiotemporal Distribution of Salmonella enterica in European Hedgehogs in Northern Italy

Growing attention is being given to the European hedgehog (Erinaceus europaeus) because of its synanthropic behaviour and its potential role in harbouring parasites, viruses, fungi and bacteria and disseminating them to several animals and humans. Salmonella are the most frequently detected zoonotic bacteria that hedgehogs could transmit through contaminating water and food sources with faeces. This study aimed to determine the prevalence and distribution of Salmonella spp. in wild hedgehogs in the Emilia-Romagna region (northern Italy). From 2019 to 2022, 212 European hedgehogs that died naturally were tested for Salmonella spp. through culture isolation. Positive samples were subjected to serological typing. A total of 82 samples tested positive for Salmonella spp., with the overall Bayesian posterior estimated prevalence ranging from 35% (95% CI: 23-47%) to a maximum of 45% (95% CI: 31-59%) during the years considered and with an overall prevalence calculated at 39% (95% CI: 33-45%). Salmonella enterica Enteritidis and Veneziana were the most prevalent detected serovars in 65% and 17% of the positive samples, respectively. Since 2021, S. Typhimurium, S. Typhimurium Monofasica, S. Zaiman, S. Hessarek, S. Muenster, S. Isangi serovars, S. enterica subsp. Diarizonae and S. enterica subsp. Houtenae have been detected. These findings show a high prevalence of Salmonella spp. in tested hedgehogs, suggesting an important role of this animal species in the epidemiology of potentially zoonotic serovars circulating in the Emilia-Romagna region.

White-Toothed Shrews (Genus Crocidura): Potential Reservoirs for Zoonotic Leptospira spp. and Arthropod-Borne Pathogens?

Three species of white-toothed shrews of the order Eulipotyphla are present in central Europe: the bicolored (Crocidura leucodon), greater (Crocidura russula) and lesser (Crocidura suaveolens) white-toothed shrews. Their precise distribution in Germany is ill-defined and little is known about them as reservoirs for zoonotic pathogens (Leptospira spp., Coxiella burnetii, Brucella spp., Anaplasma phagocytophilum, Babesia spp., Neoehrlichia mikurensis and Bartonella spp.). We investigated 372 Crocidura spp. from Germany (n = 341), Austria (n = 18), Luxembourg (n = 2) and Slovakia (n = 11). West European hedgehogs (Erinaceus europaeus) were added to compare the presence of pathogens in co-occurring insectivores. Crocidura russula were distributed mainly in western and C. suaveolens mainly in north-eastern Germany. Crocidura leucodon occurred in overlapping ranges with the other shrews. Leptospira spp. DNA was detected in 28/227 C. russula and 2/78 C. leucodon samples. Further characterization revealed that Leptospira kirschneri had a sequence type (ST) 100. Neoehrlichia mikurensis DNA was detected in spleen tissue from 2/213 C. russula samples. Hedgehogs carried DNA from L. kirschneri (ST 100), L. interrogans (ST 24), A. phagocytophilum and two Bartonella species. This study improves the knowledge of the current distribution of Crocidura shrews and identifies C. russula as carrier of Leptospira kirschneri. However, shrews seem to play little-to-no role in the circulation of the arthropod-borne pathogens investigated.

Molecular and Serological Identification of Pathogenic Leptospira in Local and Imported Cattle from Lebanon

Leptospirosis is a worldwide bacterial zoonosis for which the risk increases in warm and wet climates. Despite the suitability of the local climate for the bacteria’s persistence, Lebanon lacks a formal system of prophylaxis for the prevention of Leptospira infection in both humans and animals, and the disease’s epidemiology is unknown so far. As a preliminary step, we focused on Leptospira infection in cattle, which is of public health and economic concern. We conducted a descriptive study in cattle from the governorate of Mount Lebanon (ML) and in imported cattle. A total of 187 blood and 135 serum samples were provided. Among the 187 blood samples, 135 were from randomly selected animals from 14 herds, while the remaining 52 were from imported livestock. Serum specimens (n = 135) were obtained exclusively from cattle in the ML governorate. DNA was extracted from all blood samples and subjected to real-time PCR targeting 16S rRNA. All Leptospira-positive DNA samples were then amplified using conventional PCR (cPCR), and Leptospira species were identified via Sanger sequencing. A microscopic agglutination test (MAT) was performed on the 135 serum samples from local cattle. The real-time PCR revealed Leptospira infection in 7 of 135 local animals and 1 of 52 imported animals. DNA from six of the seven local animals and the one imported animal were amplified by cPCR and successfully sequenced, identifying the pathogen as the species L. kirschneri. Seven animals located in five out of the 14 tested herds had MAT titers ≥1 : 100. Serogroup Grippotyphosa was predominant. This is the first study to provide epidemiological data on bovine Leptospira infection in Lebanon. Pathogenic Leptospira species and serogroups were identified in both local and imported cattle. These findings highlight the cattle associated risk of Leptospira infection in Lebanon, in the contexts of farming and trade. Summary. Leptospirosis is a severe zoonotic disease that can have critical consequences for people and animals. Within the country of Lebanon, this disease has been reported, but its epidemiology is unknown so far. The present study thus provides the first description of the existence of Leptospira in cattle in Lebanon (local and imported). It also highlights the existence of different pathogenic serogroups of Leptospira in local cattle. Our results should raise public health awareness of the threat posed by this underdiagnosed disease and serve as a starting point for control efforts in Lebanon.

Synanthropic and Wild Animals as Sentinels of Zoonotic Agents: A Study of Leptospira Genotypes Circulating in Northeastern Italy

Leptospirosis is an infectious disease widely reported in veterinary practice and a worldwide zoonosis. In Northeastern Italy, different serogroups and genotypes of Leptospira have been described in ill dogs, the most commonly detected being Icterohaemorragiae (ICT) ST 17, Australis (AUS) ST 24 and ST 198, Pomona (POM) ST 117 and ST 289, and Sejroe (SEJ) ST 155. However, there is little information available on the environmental exposure to Leptospira of wild and synanthropic animals. The aim of this study was to identify the circulating genotypes in potential reservoirs to fill this gap of knowledge. Between 2015 and 2022, 681 animal carcasses collected by the Public Veterinary Service were analyzed for Leptospira with a real-time PCR-based screening test, while positive samples were genotyped by multi-locus sequence typing analysis. To carry out our study, we tested 330 hedgehogs, 105 red foxes, 108 Norway rats, 79 mice, 22 coypus, 10 bank voles, 13 grey wolves, 5 common shrews and 9 greater mouse-eared bats. Five sequence types (STs) common in dogs were also found in wild animals: ST 24, ST 198, ST 17 and ST 155 in hedgehogs, ST 17 and ST 24 in foxes, ST 17 in rats, ST 17 and ST 155 in mice, and ST 117 in a wolf. In addition, to the best of the authors' knowledge, this is the first Italian report of SEJ ST 197 in a bank vole. Furthermore, this study described a previous survey conducted in 2009 on coypus (30 animals from the province of Trento and 41 from the province of Padua), referring to a serological positivity (L. Bratislava) without any molecular detection of Leptospira. This study on Leptospira in synanthropic and wild animals highlighted the importance of increasing our epidemiological knowledge of leptospirosis and its zoonotic risks.

Identification of Pathogenic Leptospira kirschneri Serogroup Grippotyphosa in Water Voles (Arvicola terrestris) from Ruminant Pastures in Puy-de-Dôme, Central France

Rodents are the primary reservoirs for pathogenic Leptospira species, which cause leptospirosis. Among the key potential carriers are water voles, whose population outbreaks can consequently pose a major threat to human and animal health. We studied the prevalence, prominence, and epidemiology of pathogenic Leptospira species in water voles in central France. First, 46 voles were captured, and DNA was extracted from kidney, lung, liver, blood, and urine and tested for the presence of Leptospira using three molecular methods: PCR, O-antigen typing, and variable number tandem repeat (VNTR) typing. We also attempted to culture leptospires from kidney and urine samples. In addition, we investigated leptospiral antibodies in serum samples from 60 sheep using microscopic agglutination testing. These animals co-occurred with the voles, so we sought to assess their degree of exposure and involvement in pathogen dynamics. The overall prevalence of infection was 76.1% (CI_95% [61.2%, 87.4%]). The only strain found was L. kirschneri serogroup Grippotyphosa and a similar VNTR profile was acquired. Leptospires were successfully cultured from kidney and urine samples for four voles. Three sheep had low antibody titers against the Leptospira serogroup Grippotyphosa. Taken together, our results suggest the exclusive carriage of L. kirschneri serogroup Grippotyphosa among water voles in central France. Nevertheless, their ability to act as reservoir hosts that transmit the pathogen to co-occurring livestock remains unclear and merits further research.

Zoonotic pathogens linked with hedgehog diphtheric disease

Hedgehog diphtheric disease (HDD), an ulcerative skin disease with a high fatality rate, is an emerging threat to European hedgehogs (Erinaceus europaeus). We explored the potential role of a panel of zoonotic pathogens in the presumed multifactorial nature of HDD in 188 hedgehogs from 3 wildlife rescue centres in Belgium. As expected, and with a prevalence of 67% in 57 hedgehogs with skin lesions, characteristic of HDD, the occurrence of Corynebacterium ulcerans was strongly associated with the disease. Remarkably, with a prevalence of 42% in affected animals, infections with Borrelia burgdorferi sensu lato were 3.92 times more likely to be detected in HDD (95% confidence interval: 1.650-9.880; p = .0024). Overall, 40 hedgehogs tested positive for the B. burgdorferi sensu lato complex, including Borrelia afzelii (n = 30), Borrelia bavariensis (n = 7) and Borrelia spielmanii (n = 7). Other widely occurring pathogens included Salmonella (prevalence of 19%, with three pulsed-field gel electrophoresis profiles) and Leptospira sp. (prevalence of 11%, including Leptospira interrogans and Leptospira borgpetersenii), but these were not associated with the occurrence of HDD. These findings show that hedgehogs in Belgium represent a significant reservoir of multiple zoonotic bacteria, of which toxigenic C. ulcerans and B. burgdorferi sensu lato are associated with widespread hedgehog skin pathology and mortality.

Circulating serogroups of Leptospira in swine from a 7-year study in France (2011–2017)

Background

Leptospirosis is a widespread zoonotic disease caused by pathogenic Leptospira and is responsible for significant economic porcine livestock losses. Knowledge of Leptospira serogroups and their distributions is important for evaluation of the relevance of leptospirosis management measures, including use of the prophylactic vaccine that was recently made available in France. A retrospective study was conducted to determine the relationships between different circulating Leptospira serogroups. Pigs from across France presenting clinical signs suggestive of leptospirosis were tested with the microagglutination test (MAT) between 2011 and 2017. We used weighted averages to determine serogroup distributions according to MAT results and considering cross-reactions.

Results

A total of 19,395 pig sera, mostly from Brittany, were tested, and 22.7% were found to be positive for at least one Leptospira serogroup. Analysis of the 4,346 seropositive results for which the putative infective serogroup could be defined, revealed that two out of ten serogroups were much more frequent than the others: Australis (48.5%) and Icterohaemorrhagiae (38.2%). Other serogroups, including Autumnalis, Panama, Ballum, Tarassovi, Sejroe, Grippotyphosa, Bataviae, and Pomona, were less common.

Conclusions

Although diagnostic laboratory data cannot be extrapolated to infer the distribution of Leptospira serogroups at the nationwide scale in France, the analysis of such data can provide an overview of the relationship between circulating Leptospira serogroups in space and time. During the last decade, protection against the serogroups Australis and Icterohaemorrhagiae would have prevented most of the clinical porcine leptospirosis cases in the large number of farms that we studied. In the future, epidemiological information related to circulating Leptospira serogroups should be extracted from data with a standardized approach for use in nationwide or international surveillance and prophylactic strategy support.

First Isolation and Molecular Typing of Pathogenic and Intermediate Leptospira Species from Urine of Symptomatic Dogs

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.

Of Mice, Cattle, and Men: A Review of the Eco-Epidemiology of Leptospira borgpetersenii Serovar Ballum

In New Zealand (NZ), leptospirosis is a mostly occupational zoonosis, with >66% of the recently notified cases being farm or abattoir workers. Livestock species independently maintain Leptospira borgpetersenii serovar Hardjo and L. interrogans serovar Pomona, and both are included in livestock vaccines. The increasing importance in human cases of Ballum, a serovar associated with wildlife, suggests that wildlife may be an overlooked source of infection. Livestock could also act as bridge hosts for humans. Drawing from disease ecology frameworks, we chose five barriers to include in this review based on the hypothesis that cattle act as bridge hosts for Ballum. Using a narrative methodology, we collated published studies pertaining to (a) the distribution and abundance of potential wild maintenance hosts of Ballum, (b) the infection dynamics (prevalence and pathogenesis) in those same hosts, (c) Ballum shedding and survival in the environment, (d) the exposure and competency of cattle as a potential bridge host, and (e) exposure for humans as a target host of Ballum. Mice (Mus musculus), rats (Rattus rattus, R. norvegicus) and hedgehogs (Erinaceus europaeus) were suspected as maintenance hosts of Ballum in NZ in studies conducted in the 1970s–1980s. These introduced species are distributed throughout NZ, and are present on pastures. The role of other wildlife in Ballum (and more broadly Leptospira) transmission remains poorly defined, and has not been thoroughly investigated in NZ. The experimental and natural Ballum infection of cattle suggest a low pathogenicity and the possibility of shedding. The seroprevalence in cattle appears higher in recent serosurveys (3 to 14%) compared with studies from the 1970s (0 to 3%). This review identifies gaps in the knowledge of Ballum, and highlights cattle as a potential spillover host. Further studies are required to ascertain the role that wild and domestic species may play in the eco-epidemiology of Ballum in order to understand its survival in the environment, and to inform control strategies.

Exposure of Free-Ranging Wild Animals to Zoonotic Leptospira interrogans Sensu Stricto in Slovenia

Simple Summary

Wildlife can serve as a reservoir for highly contagious and deadly diseases, many of which are infectious to domestic animals and/or humans. Wildlife pathogen and disease surveillance is, thus, an essential tool that can provide valuable information on population health status and protect human health. Blood samples from 244 wild animals and 5 from carcasses were tested for specific antibodies against Leptospira serovars in Slovenia between 2019 and 2020 using the microscopic agglutination test. The results confirm that various wildlife species were exposed to Leptospira interrogans and may be used as a sentinel for leptospirosis, which is considered a significant health threat to other wildlife species and to humans.

Abstract

A total of 249 serum samples from 13 wild animal species namely fallow deer (Dama dama, n = 1), roe deer (Capreolus capreolus, n = 80), red deer (Cervus elaphus, n = 22), chamois (Rupicapra rupicapra, n = 21), mouflon (Ovis musimon, n = 4), brown hare (Lepus europaeus, n = 2), nutria (Myocastor coypus, n = 1), red fox (Vulpes vulpes, n = 97), stone marten (Martes foina, n = 12), European badger (Meles meles, n = 2), golden jackal (Canis aureus, n = 2) Eurasian lynx (Lynx lynx, n = 2) and grey wolf (Canis lupus, n = 3) were analysed for the presence of antibodies against Leptospira interrogans sensu stricto. Serum samples were examined via the microscopic agglutination test for the presence of specific antibodies against Leptospira serovars Icterohaemorrhagiae, Bratislava, Pomona, Grippotyphosa, Hardjo, Sejroe, Australis, Autumnalis, Canicola, Saxkoebing and Tarassovi. Antibodies to at least one of the pathogenic serovars were detected in 77 (30.9%; CI = 25–37%) sera. The proportion of positive samples varied intraspecifically and was the biggest in large carnivores (lynx, wolf and jackal; 86%), followed by mezzo predators: stone marten (67%) and red fox (34%), and large herbivores: red deer (32%), roe deer (25%), alpine chamois (10%) and mouflon (0%). Out of the 77 positive samples, 42 samples (53.8%) had positive titres against a single serovar, while 35 (45.4%) samples had positive titres against two or more serovars. The most frequently detected antibodies were those against the serovar Icterohaemorrhagiae. The present study confirmed the presence of multiple pathogenic serovars in wildlife throughout Slovenia. It can be concluded that wild animals are reservoirs for at least some of the leptospiral serovars and are a potential source of leptospirosis for other wild and domestic animals, as well as for humans.

Can the European Hedgehog (Erinaceus europaeus) Be a Sentinel for One Health Concerns?

Erinaceus europaeus is a cosmopolitan mammalian species broadly distributed in Europe, from natural to suburban areas. Due to its ecological role and susceptibility to distinct zoonotic agents, E. europaeus could be a suitable sentinel candidate for many global problems that negatively affect human and animal health. Hedgehogs can work as bioindicators to environmental contamination and can be hosts for multiple tickborne zoonotic agents. Thus, people who directly or indirectly make physical contact with this species are exposed to a variety of threats. Moreover, it has also been studied as an indicator for antibiotic resistance, which was already confirmed for tetracyclines. Additionally, it was also reported as a reservoir for methicillin-resistant Staphylococcus aureus (MRSA). More recently, hedgehogs have been recently recognised as potential reservoirs of MERS-CoV-like strains. Among other animals, this species can possibly represent an intermediate reservoir for SARS-CoV-2. The aim of this review is to briefly expose the scientific attainments about hedgehog health, namely agents, diseases, and threats that significantly affect general health concerns and that contribute to achieve One Health principles.

Hedgehogs as a Potential Source of Zoonotic Pathogens-A Review and an Update of Knowledge

Simple Summary

Up to date studies indicate that wild hedgehogs may act as carriers and/or hosts for bacterial, viral, and fungal pathogens with zoonotic potential, posing a significant threat to humans. The same applies to domestic hedgehogs, which are increasingly kept as pets. Considering the potential risk of infection to humans through close contact with hedgehogs or the contaminated environment they inhabit, current data on the prevalence of various zoonotic pathogens in these animals is desirable.

Abstract

Hedgehogs are small insectivorous mammals common across Europe, Asia, and Africa. The increased encroachment of humans into hedgehog habitats has disrupted the human-animal-environment interface. With growing interest in the zoonotic diseases of wildlife species, more studies have been devoted to this subject in the last few years. These papers provide information about known and new emerging diseases. Here we review the current knowledge regarding bacterial, viral, protozoic, and mycotic pathogens with zoonotic potential and assess the importance of hedgehogs as their carriers. Both wild and pet hedgehogs were included in the review. Data from several countries and various hedgehog species were included. The study shows the importance of hedgehogs as carriers of zoonotic diseases and reservoirs of zoonotic pathogens in varied habitats.

Molecular Typing of Pathogenic Leptospira Species Isolated from Wild Mammal Reservoirs in Sardinia

Simple Summary

Leptospirosis is caused by pathogenic spirochaetes of the genus Leptospira. Humans can become infected with these bacteria through direct contact with urine from infected animals or indirectly through interaction with a urine contaminated environment. Among wildlife species, rodents are considered the primary reservoir hosts for leptospirosis in rural and urban environments. Epidemiological data, regarding leptospirosis in various wild species in Europe, suggest that these animals play a different role in leptospiral persistence. Unfortunately, studies on the presence and typing of Leptospira species in wild mammals are lacking in Sardinia. The aim of the present study was to investigate the prevalence of Leptospira species in wild mammals. Kidneys collected from carcasses were analyzed by culture and molecular testing. Greater positivity was found in hedgehogs, followed by weasels and rodents. The results obtained suggest that Sardinian fauna may play a possible sentinel role in the transmission cycle of leptospirosis to humans. Gathering this information in different wildlife species is crucial for better understanding of the epidemiology of leptospirosis and for the development of appropriate prevention measures.

Abstract

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.

Serological and molecular survey of Leptospira spp. infections in wild boars and red foxes from Southeastern France

Background and Aim:

Leptospirosis is a zoonotic disease. Information on the recent prevalence of Leptospira in hunted wild animals is limited, particularly in southeastern France. A cross-sectional survey was conducted to assess the prevalence and diversity of Leptospira spp. among wild boars (Sus scrofa) and red foxes (Vulpes vulpes) from two military camps in Southeastern France.

Materials and Methods:

Serological analyses were performed using microscopic agglutination tests and polymerase chain reaction (PCR) assays were used to demonstrate Leptospira spp. infection from boar kidney DNA extracts.

Results:

According to the species, the positive sera were obtained from 18% of 358 boars and 6 % of 64 foxes tested. The prevalence rate is significantly higher (p≤0.02) in boars than in foxes. In wild boar, Australis represents the most recorded serogroup (15.9%), followed by Sejroe (2.8%) and icterohaemorhagiae (2.8%). In red fox, icterohaemorhagiae represents the most recorded serogroup (6.25%), followed by Sejroe (1.57%) and Hebdomadis (1.57%). PCR-based detection of Leptospira DNA was positive in 6/62 (9.6%) of the wild boars tested.

Conclusion:

The results of this study confirmed the importance of wild boar in the epidemiology of leptospirosis among wildlife in Southeastern France. Due to their predatory behavior and their varied diet, mainly composed of small mammals, red foxes could be considered sentinel animals of environmental contamination with leptospires.

Successful Leptospira genotyping strategy on DNA extracted from canine biological samples

Leptospirosis is an emerging worldwide zoonosis with a changing epidemiology responsible for an acute disease in humans and dogs. A better knowledge of the responsible bacterium Leptospira and in particular its various serovars and serogroups prevalence is essential for better diagnosis and prevention of the disease. The gold standard for leptospirosis diagnosis is the Microscopic Agglutination Test (MAT) but it requires long and fastidious laboratory work and sometimes results in controversial data. For these reasons, PCR-based techniques for detection of pathogenic leptospiral DNA in biological samples are currently replacing the MAT. However, these strategies do not provide any information regarding the infecting serovar or serogroup. In this study, an optimized genotyping method is described to allow the identification of Leptospira ssp. directly at serovars level using DNA extracted from canine blood and urine. 16S rDNA, Variable Number Tandem Repeat (VNTR) and Multispacer Sequence Typing (MST) protocols were adapted to biological samples. Eighty-eight DNA samples were analyzed from 72 different European canine clinical cases of leptospirosis confirmed by real-time PCR. 92% of DNA samples with Ct values below 34 were fully typed, and typing success decreased to about 30% for the other samples. Typing failure also showed a specie-specific correlation, with 63% of complete typing for L. interrogans and only 40% for L. kirschneri. Additionally, an exact match was observed between serological and molecular data for the few investigated cases where MAT data were available. This methodology is a suitable alternative to the MAT for determining the infecting serovar when Leptospira DNA from blood or urine is detected at Ct values below 34, contributing to clinical surveillance of leptospirosis.

Crested Porcupine (Hystrix cristata L.): A New Potential Host for Pathogenic Leptospira Among Semi-Fossorial Mammals

Wildlife plays a pivot role in the epidemiology of leptospirosis and rodents have a reservoir function for several Leptospira serogroups. The crested porcupine is the largest rodent of the Italian fauna and shares the same environment with red foxes, badgers, coypus and wild boars that are known to be infected by Leptospira. Between 2018 and 2019 the seroprevalence of Leptospira in crested porcupine was investigated for the first time. Overall 7 out of 14 sera (50 %) were found positive to Leptospira. Icterohaemorrhagiae resulted as the most detected serogroup (57 %) followed by Pomona, Australis and Sejroe. The highest titer (1:1600) was detected for the serogroup Australis. These results indicate that porcupines could be infected by several serogroup of Leptospira and the role of reservoir or accidental host need to be addressed. Further investigations are necessary in order to clarify the leptospirosis - epidemiology - wildlife framework in light of its potential zoonotic source.

Detection of Leptospira interrogans in Hedgehogs from Central China

Background: Leptospira is the causative agent of leptospirosis, a zoonotic disease of global importance. To have a better understanding on the host species of Leptospira, we investigated the prevalence of Leptospira species in hedgehogs in Central China. Materials and Methods: Hedgehogs were captured in Hubei Province, China in May and October, 2018. Total DNA was extracted from the kidney tissues of hedgehogs for determining the Leptospira species by PCR amplification of the rrs2, secY, and flaB genes with genus-specific primers. Results: PCR amplification indicated that the positive rate of hedgehogs to the rrs2, secY, and flaB genes were 19.5% (8/41), 12.2% (5/41), and 9.8% (4/41), respectively. The homology of the partial sequence of rrs2, secY, and flaB genes were 99.0-100% among the Leptospira strains from hedgehogs. Phylogenetic analysis revealed that Leptospira species detected in this study clustered together with Leptospira interrogans. Conclusions: We detected L. interrogans from hedgehogs in Central China, suggesting hedgehogs are the hosts of L. interrogans.

Muskrats are greater carriers of pathogenic Leptospira than coypus in ecosystems with temperate climates

Knowledge on the possible sources of human leptospirosis, other than rats, is currently lacking. To assess the distribution pattern of exposure and infection by Leptospira serogroups in the two main semi-aquatic rodents of Western France, coypus (Myocastor coypus) and muskrats (Ondatra zibethicus), results of micro-agglutination testing and renal tissue PCR were used. In coypus, the apparent prevalence was 11% (n = 524, CI95% = [9% - 14%]), seroprevalence was 42% (n = 590, CI95% = [38% - 46%]), and the predominant serogroup was Australis (84%). In muskrats, the apparent prevalence was 33% (n = 274, CI95% = [27% - 39%]), seroprevalence was 57% (n = 305, CI95% = [52% - 63%]), and the predominant serogroup was Grippotyphosa (47%). Muskrats should therefore be considered an important source of Grippotyphosa infection in humans and domestic animals exposed in this part of France.

Leptospirosis, one neglected disease in rural Senegal

A serological study was carried out in two Senegalese villages located in the Sine-Saloum region in order to estimate the presence of anti-leptospiral antibodies in humans and animals, and to identify the predominant serogroups. Seven hundred and forty-nine serum samples were collected from humans (n = 545), dogs (n = 33), donkeys (n = 20), goats (n = 52), sheep (n = 43) and N'Dama cattle (n = 56), all originated from Dielmo and Ndiop villages. All samples were tested for different serovars of pathogenic Leptospira species by the microscopic agglutination test. Considering titres ≥ 1:100, 7.7% [CI 95:5.5 to 9.9] on the 545 human blood samples tested and 42.2% [CI95 :35.4 to 48.9] on the 204 animal blood samples tested were found to be positive to one or more serovars. The results obtained indicate that the Australis serogroup is the most prevalent serogroup in human (67.3%) and cattle (27.3%). Serogroup Icterohaemorhagiae is the most frequent serogroup in goat (55.6%) and donkey (37.5%). Canicola (23.4%), Icterohaemorhagiae (21.1%) and Australis (12.5%) serogroups are the most prevalent serogroups in dogs. This study shows that diverse Leptospira serovars occur in a wide range of wild and domestic mammal species, as well as in humans in Senegal. However, further studies are needed to better understand the complexity of Leptospira epidemiology in Africa, identify the reservoirs of different serogroups and estimate its impact on livestock. Understanding the multi-host epidemiology of leptospirosis is essential to control and prevent the disease.

An outbreak of leptospirosis among kayakers in Brittany, North-West France, 2016

In September 2016, a cluster of seven kayakers with clinical symptoms of leptospirosis with onset since July 2016 was reported to French health authorities. Human and animal investigations were undertaken to describe the outbreak, identify the likely place and source of infection and implement necessary control measures. We identified 103 patients with clinical symptoms of leptospirosis between 1 June and 31 October 2016 who lived in the Ille-et-Vilaine district in Brittany. Of these, 14 (including the original seven) reported contacts with the river Vilaine during the incubation period and were defined as outbreak cases: eight were confirmed by serology tests or PCR and six were probable without a laboratory confirmation for leptospirosis. All 14 cases were kayakers. Three distinct contamination sites were identified on a 30 km stretch of the river Vilaine. Nine cases reported having skin wounds while kayaking. None were vaccinated against leptospirosis. The outbreak was attributed to Leptospira kirschneri serogroup Grippotyphosa. Animal investigations did not allow identifying the possible reservoir. Leptospirosis outbreaks associated with freshwater sports are rare in temperate climates. The prevention of such outbreaks requires control of potential animal reservoirs in zones such as the Vilaine valley and that kayakers adopt the recommended individual prevention measures.

Evidence of Leptospira species and their significance during reintroduction of Eurasian beavers (Castor fiber) to Great Britain

The Scottish Beaver Trial (SBT) reintroduced the Eurasian beaver (Castor fiber) in 2009 using wild-caught Norwegian beavers. This included a six-month prerelease quarantine in Devon, England. The International Union for Conservation of Nature (IUCN) and government guidelines for health screening were followed, including testing for Leptospira species. Unlicensed beavers, from Germany, were also identified in Scotland (Tayside) and Devon (later forming the River Otter Beaver Trial (ROBT)) and were health-screened under licence. Due to positive Leptospira species results and lack of prerelease screening in ROBT and Tayside, beavers from Germany and Norway (range sources) were screened. One hundred and fifty-six samples from 151 beavers were analysed by Leptospira species quantitative PCR (qPCR) (n=73 kidney (postmortem)/urine samples (antemortem)) or microscopic agglutination test (MAT, Leptospira pools 1-6) (n=83 serum samples). No beavers from Norway (95 per cent confidence interval (CI) 0-5.6 per cent, n=52), Tayside or SBT postrelease (95 per cent CI 0-4.6 per cent, n=63) tested positive. Seven beavers from Germany and Devon were positive. This gives an overall 9.3 per cent (95 per cent CI 5.2-15.1 per cent) exposure level, of which 4.6 per cent (95 per cent CI 1.9-9.3 per cent) suggested infection on a positive qPCR (n=1) or MAT titre of at least 1/400 (n=6), although none had abnormal physical, biochemical or haematological changes. This study suggests that Leptospira species infection in wild Eurasian beavers occurs at a low level, has no sex bias and does not appear to cause significant morbidity or mortality.

House Mice as a Real Sanitary Threat of Human and Animal Leptospirosis: Proposal for Integrated Management

Leptospirosis is a reemerging zoonosis and ranges in severity from benign to sometimes fatal. In cattle, infection may be responsible for abortion and infertility cases causing economic losses. Humans may be contaminated through direct contact with urine of infected animals or indirectly though interaction with urine-contaminated environment. Many wildlife species living close to cattle, especially commensal rodents may play a role in the transmission of leptospires. Because little is known on the epidemiology of nonmaintenance Leptospira serovars, appropriate management is still limited. On a French farm where human and cattle leptospirosis were detected, the transmission cycle was explored to propose appropriate mitigation measures. For that, commensal rodents present on the farm were trapped and their leptospires carriage was studied by molecular methods. Trapped mice were shown to carry two pathogenic Leptospira species (L. interrogans and L. kirschneri). Since these 2 serogroups were simultaneously detected in the trapped mice and in the cows of this farm, we suspected an initial Leptospira transmission from mice to cows requiring an effective management of mice on this farm. Because resistance to anticoagulant rodenticides due to Vkorc1 mutations has been largely described in rodents and first-generation anticoagulant rodenticides seemed to be inefficient in controlling mice on this farm, susceptibility of these mice to anticoagulants has been characterized by Vkorc1 sequencing. 50% of the trapped mice carried mutations in the Vkorc1 gene leading to severe resistance to first-generation anticoagulants. The management of such mice that are a real sanitary threat can be achieved only by using the most toxic second-generation anticoagulants or nonanticoagulant solutions.

Pathogenic Leptospira species are widely disseminated among small mammals in Atlantic Forest biome

Leptospirosis is a common worldwide bacterial zoonosis and has been studied in One Health approaches. Small mammals are described as the most important maintenance reservoirs of several pathogens in nature, including leptospires. The aim of this study was to identify infection by leptospires among small mammals on the Atlantic forest biome and evaluate their potential as carriers of these spirochetes. A total of 153 small mammals belonging to orders Rodentia and Didelphimorphia (distributed on 17 genera and 22 species) were captured. Blood and kidney samples were collected from animals and a conventional PCR targeted on lipL32 gene was conducted on renal tissues. Species identification was performed in eight samples by sequencing of rrs gene. A total of 28% of the animals presented lipL32 PCR-positive, and four pathogenic Leptospira species (L. interrogans, L. borgpetersenii, L. santarosai and L. noguchii) were identified. This study highlights the role of small mammals as carriers of leptospires on the Atlantic Forest representing a potential source of pathogenic Leptospira spp infection for both humans and domestic animals.

Advances and challenges in barcoding pathogenic and environmental Leptospira

Leptospirosis is a zoonotic bacterial disease of global importance. A large spectrum of asymptomatic animal hosts can carry the infection and contribute to the burden of human disease. Environmental sources of human contamination also point to the importance of a hydrotelluric reservoir. Leptospirosis can be caused by as many as 15 different pathogenic or intermediate Leptospira species. However, classification of these bacteria remains complicated through the use of both serological and genetic classification systems that show poor correlation. With the advent of molecular techniques, DNA-based barcoding offers a conceptual framework that can be used for leptospirosis surveillance as well as source tracking. In this review, we summarize some of the current techniques, highlight significant successes and weaknesses and point to the future opportunities and challenges to successfully establish a widely applicable barcoding scheme for Leptospira.

Leptospira reservoirs among wildlife in Brazil: Beyond rodents

Leptospirosis is a disease of great importance in tropical regions. Infection occurs mainly through contact with water contaminated with the urine of infected animals, especially that of rodents. Despite the diversity and abundance of wild fauna in Brazil, little is known about the role of other wild species in the epidemiology of leptospirosis. This study aimed to investigate new reservoirs of Leptospira among wildlife in Brazil, using serological and molecular diagnoses in a large-sized sample. Biological samples were collected from 309 free-ranging mammals, belonging to 16 species. The majority of the animals included were opossums (Didelphis albiventris) and coatis (Nasua nasua). Blood and urine samples were subjected to the microscopic agglutination test (MAT) and real-time PCR, respectively. Genetic characterization of genomospecies was performed using PCR amplicons. Statistical analysis was applied to test associations between positive diagnoses and age, sex, season and type of environment. The prevalence of infection found via MAT and PCR was 11% and 5.5%, respectively. If these tests are taken to be complementary, the overall prevalence was 16%. The most common serogroups were Djasiman and Australis, while L. santarosai was the prevalent genomospecies. Significant differences in prevalence between animal species were observed. Greater risk of infection was detected among adult opossums than among young ones. The influence of each serogroup and genomospecies was tested for the same variables, and this revealed higher risk of infection by L. santarosai among male opossums than among females. The present study highlights the exposure and carrier status of several wild species in Brazil and it indicates that coatis and other carnivores are priorities for further investigations.

A systematic review of leptospirosis on wild animals in Latin America

Leptospirosis is a bacterial systemic infection which affects domestic animals and wildlife, as well as humans. Many wild animals act as reservoirs of leptospires. Nevertheless, the real role of wildlife animals as source of infection to livestock and humans, as well as the most important reservoirs and leptospiral strains remains unclear. This systematic review assesses the available data about wildlife and their biomes in Latin America, concerning to leptospiral infection. In addition, we discuss the development of the research on leptospirosis in wildlife in this region. After the application of exclusion criteria, 79 papers were analyzed, comprising 186 species, 122 genus, 53 families, and 19 orders from four classes. Mammals were the most studied class, followed by Amphibian, Reptile, and Aves. The Icterohaemorrhagiae serogroup was predominant in most biomes and many orders. A small number of antigens detected the majority of seroreactive animals of each class, and a smaller panel may be used at microscopic agglutination test. Further studies must always consider edaphoclimatic conditions besides only host class or species, in order to obtain a broader understanding of the wild epidemiological cycle of leptospirosis in the region. In conclusion, direct and indirect evidences demonstrate that leptospirosis is largely widespread among wildlife in all biomes of Latin America. Moreover, more research on the role of wildlife on the epidemiology of leptospirosis and its impact on livestock and public health are required, particularly focusing on direct detection of the agent.

Investigation on predominant Leptospira serovars and its distribution in humans and livestock in Thailand, 2010-2015

BACKGROUND

Leptospirosis is a worldwide zoonotic bacterial disease caused by infection with leptospires. Leptospirosis in humans and livestock is an endemic and epidemic disease in Thailand. Livestock may act as reservoirs for leptospires and source for human infection.

METHODOLOGY/PRINCIPAL FINDINGS

Data on leptospirosis infection in humans and livestock (Buffaloes, Cattle, and Pigs) species during 2010 to 2015 were analyzed. Serum samples were examined using Microscopic Agglutination Test (MAT) to identify antibodies against Leptospira serovars using a cut-off titer ≥ 1:100. The seroprevalence was 23.7% in humans, 24.8% in buffaloes, 28.1% in cattle, and 11.3% in pigs. Region specific prevalence among humans and livestock was found in a wide range. The most predominant serovars were Shermani, followed by Bratislava, Panama, and Sejroe in human, Shermani, Ranarum, and Tarassovi in buffaloes, and Shermani and Ranarum in cattle and pigs. Equally highest MAT titers against multiple serovars per one sample were found mainly in buffaloes and cattle showing equally titers against Ranarum and Shermani. The correlations of distribution of serovars across Thailand's regions were found to be similar in pattern for cattle but not for buffaloes. In humans, the serovar distribution in the south differed from other regions. By logistic regression, the results indicated that livestock is more susceptible to infection by serovar Shermani when compared to humans.

CONCLUSIONS/SIGNIFICANCE

This study gives a detailed picture of the predominance of Leptospira serovars in relation to region, humans and typical livestock. The broad spatial distribution of seroprevalence was analyzed across and within species as well as regions in Thailand. Our finding may guide public health policy makers to implement appropriate control measures and help to reduce the impact of leptospirosis in Thailand.