Detection of pathogenic Leptospira species associated with phyllostomid bats (Mammalia: Chiroptera) from Veracruz, Mexico

Leptospira infection in bats in Vietnam

Bats from three provinces in Vietnam (Lai Chau, Son La, and Dong Thap) were examined for the presence of pathogenic Leptospira or specific antibodies using polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and microscopic agglutination test (MAT). Tissue specimens from 298 bats belonging to 11 species were analyzed using a real-time PCR assay specific for leptospires of pathogenic species. Leptospiral DNA was identified in 40 bats from following species: Rousettus amplexicaudatus (5/9; 55.5 %), Rousettus leschenaultii (17/42; 40.4 %), Myotis hasseltii (8/25; 32 %), Taphozous longimanus (3/12; 25 %), and Eonycteris spelaea (7/32; 21.9 %). Based on secY phylogeny, sequences from M. hasseltii bore a strong resemblance to L. borgpetersenii. Sequences from other species revealed unique lineages: one of them resembled Leptospira sp., previously identified in Rousettus madagascariensis (Madagascar) and Rousettus aegyptiacus (South Africa); the second lineage showed close relation to L. kirshneri; and the third held an intermediary position between L. noguchii and L. interrogans. Through ELISA, anti-Leptospira antibodies were found in 83 of 306 bats, with the highest seroprevalence observed in R. leschenaultii (44/48; 91.6 %), R. amplexicaudatus (6/8; 75 %), and E. spelaea (19/25; 76 %). 66 of these ELISA-positive samples were tested using MAT; 41 of them were confirmed in MAT as positive. The predominant serogroups in our study were Tarassovi and Mini.

Isolation and molecular identification of Leptospira santarosai and Leptospira interrogans in equines from eastern Mexico

Leptospirosis is an infectious disease with a worldwide distribution, which represents a major challenge in animal production across developing countries, mainly in tropical areas. Horses are particularly susceptible to the disease, presenting manifestations ranging from subclinical to the development of uveitis that compromises the visual health of the animals. In recent years, serological studies have been carried out in equid populations from America, demonstrating high exposure. For this reason, the aim of this study was to demonstrate microbiologically and molecularly the presence of the members of the genus Leptospira in urine samples from equids in an endemic state of leptospirosis in Mexico, and to detect the serological presence of anti-Leptospira antibodies in the sampled animals. For this reason, blood and urine samples were collected from 28 horses and one mule from three localities in the state of Veracruz, Mexico. Urine samples were inoculated in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium, and the recovered isolates were typed using a short Multi Locus Sequence Typing scheme. Amplifications of the expected size were subjected to sequencing, and the recovered sequences were compared with those of reference deposited in GenBank using the BLAST tool. To identify their phylogenetic position, we performed a phylogenetic reconstruction using the maximum likelihood method. Additionally, Microscopic Agglutination test was performed on the serum samples to identify anti-Leptospira antibodies. We recovered 16 urine isolates which tested positive for the presence of Leptospira DNA. The phylogenetic reconstruction and the MLST analysis confirmed the presence of several genotypes of Leptospira interrogans and Leptospira santarosai. An overall serological frequency of 97.1 % was detected. Our results represent the first record of the presence of Leptospira through bacteriological isolates in equids from Mexico.

Study on the relation of the characteristics of the capture sites with the Leptospira spp. occurrence in bats and rodents from Yucatan, Mexico

This study aims to describe the natural Leptospira occurrence in small mammals from Yucatan, Mexico, and to explore the relation between the characteristics of the capture sites and the Leptospira occurrence. Bats and rodents were captured in five sites of Yucatan state, and from them, a kidney fragment was collected that was used in the genomic DNA extraction. Leptospira DNA was identified by PCR targeting the 16S-rRNA and LipL32 genes. Additionally, a bioinformatic analysis was carried out to know the Leptospira species and was corroborated with a phylogenetic tree. The assemblage of small mammals was compound of 82 (51.2 %) bats and 78 (48.8 %) rodents. A global frequency (bats plus rodents) of Leptospira occurrence of 21.2 % (34/160) was observed; in bats, it was 21.9 % (18/82), and in rodents, 20.5 % (16/78). The phylogenetic trees based on LipL32 gene showed that the recovered sequences most closely resemble the species L. borgpetersenii and L. noguchii. The ordination of the capture sites with tropical deciduous forests as original vegetation is more related to the abundance of Leptospira-infected rodents. The ordination of the capture sites with tropical sub-deciduous forests as original vegetation is more related to the diversity of Leptospira-infected bat species. The canonical ordering of the capture sites is by the original vegetation type and the diversity and abundance of Leptospira-infected bat and rodent species.

Molecular detection of Theileria cervi in equids from México

Equine piroplasmosis is a parasitic illness caused by various protozoa of the Babesia and Theileria genera, which parasitize within red blood cells. The transmission of these pathogens occurs through certain genus of ticks, including Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus. In recent times, an increase in the identification of new Theileria species and genotypes has been observed. This is further complicated by the presence of mixed Theileria infections in both mammals and tick vectors, particularly in regions where wildlife and livestock share habitats and vectors. Therefore, the objective of this study is to document the occurrence of Theileria cervi in a non-typical host. A total of 88 horses (Equus caballus) and 10 donkeys (Equus asinus) were sampled in three municipalities in Veracruz, Mexico. Molecular techniques were employed to identify Babesia/Theileria through the amplification of a segment of the 18S-rDNA and hsp70 genes. The phylogenetic reconstruction grouped the obtained sequences into a monophyletic cluster alongside sequences of T. cervi. This work represents the first documented occurrence of T. cervi in equids. These findings have significant implications from an epidemiological point of view. In addition, further studies are needed to determine the distribution and pathogenicity of this species for domestic animals and to develop effective control strategies.

Prevalence and Characteristics of Novel Pathogenic Leptospira Species in Bats in Yunnan Province, China

Leptospirosis has been identified as a zoonotic disease caused by pathogenic spirochetes of the bacterial genus Leptospira. Rodents are considered the primary hosts of these bacteria, whereas many recent studies suggest that bats may serve as potential natural reservoirs. However, studies on pathogenic spirochetes hosted by bat populations still need to be completed in China. In this study, a total of 276 bats belonging to five genera collected in Yunnan Province (Southwest China) from 2017 to 2021 were included in the screening. Pathogenic spirochetes were detected by PCR amplification and sequencing targeting four genes (rrs, secY, flaB, and LipL32), resulting in 17 positive samples. Phylogenetic analysis based on multi-loci concatenated sequences, inferred by MLST approach, identified the strains as two novel Leptospira species within the pathogenic group. Of note, only Rousettus leschenaultii was found to harbor these spirochetes, suggesting it may be one of the potential natural reservoirs in circulating leptospires in this region. Nevertheless, the pathogenesis and transmission dynamics still need to be fully understood, requiring in-depth studies on other animals and the surrounding population.

A review of the diet of the common vampire bat (Desmodus rotundus) in the context of anthropogenic change

The common vampire bat (Desmodus rotundus) maintains a diverse, sanguivorous diet, utilizing a broad range of prey taxa. As anthropogenic change alters the distribution of this species, shifts in predator-prey interactions are expected. Understanding prey richness and patterns of prey selection is, thus, increasingly informative from ecological, epidemiological, and economic perspectives. We reviewed D. rotundus diet and assessed the geographical, taxonomical, and behavioral features to find 63 vertebrate species within 21 orders and 45 families constitute prey, including suitable host species in regions of invasion outside D. rotundus' range. Rodentia contained the largest number of species utilized by D. rotundus, though cattle were the most commonly reported prey source, likely linked to the high availability of livestock and visibility of bite wounds compared to wildlife. Additionally, there was tendency to predate upon species with diurnal activity and social behavior, potentially facilitating convenient and nocturnal predation. Our review highlights the dietary heterogeneity of D. rotundus across its distribution. We define D. rotundus as a generalist predator, or parasite, depending on the ecological definition of its symbiont roles in an ecosystem (i.e., lethal vs. non-lethal blood consumption). In view of the eminent role of D. rotundus in rabies virus transmission and its range expansion, an understanding of its ecology would benefit public health, wildlife management, and agriculture.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42991-023-00358-3.

Neuro-leptospirosis - A batty diagnostic enigma

Leptospirosis is an important, worldwide zoonotic, with a high incidence in warm-climate and tropical countries. Leptospirosis has a broad spectrum of manifestations, from a non-specific febrile illness to severe disease with multi-organ involvement. Transmission typically occurs following exposure to urine from infected animals, in particular domesticated animals such as rodents and cattle. Leptospira species have been identified in bats, however bat-human transmission is uncertain, and bat-associated leptospirosis in humans is seldom reported. We report a unique case of severe neuro-leptospirosis resulting from bat exposure with an unusual manifestation of a non-traumatic subarachnoid haemorrhage, and the diagnostic challenges it presented.

An overview of bats microbiota and its implication in transmissible diseases

Recent pandemic events have raised the attention of the public on the interactions between human and environment, with particular regard to the more and more feasible transmission to humans of micro-organisms hosted by wild-type species, due to the increasing interspecies contacts originating from human’s activities. Bats, due to their being flying mammals and their increasing promiscuity with humans, have been recognized as hosts frequently capable of transmitting disease-causing microorganisms. Therefore, it is of considerable interest and importance to have a picture as clear as possible of the microorganisms that are hosted by bats. Here we focus on our current knowledge on bats microbiota. We review the most recent literature on this subject, also in view of the bat’s body compartments, their dietary preferences and their habitat. Several pathogenic bacteria, including many carrying multidrug resistance, are indeed common guests of these small mammals, underlining the importance of preserving their habitat, not only to protect them from anthropogenic activities, but also to minimize the spreading of infectious diseases.

Leptospira interrogans in bats in Rio Grande do Sul State, Brazil: epidemiologic aspects and phylogeny

Leptospirosis is an infectious disease caused by Leptospira spp. and affects animals and humans. Reports of leptospirosis in bats have increased and prompted epidemiological research in Brazil. This study aimed to perform a molecular and epidemiological investigation of pathogenic Leptospira spp. in bat kidneys. The total DNA was extracted from 102 kidney samples from chiropterous of different species and cities in Rio Grande do Sul State (RS), Brazil. The polymerase chain reaction was used to amplify a fragment corresponding to lipL32 gene, which is only present in pathogenic Leptospira spp. lipL32 gene was detected in 22.5% (23/102) of the bat kidney tissues. Phylogenetic analysis showed that L. interrogans is circulating in bats in RS. Most species of the bats collected were insectivores. Pathogenic Leptospira spp. detection in bats demonstrated that these animals participate in the infection chain of leptospirosis and, therefore, may play as reservoirs and disseminators of this microorganism. Thus, it is important to monitor infectious agents, especially with zoonotic potential in bats.

Spatial epidemiology of Leptospira sp. exposure in bovines from Veracruz, México

Bovine leptospirosis is a bacterial disease that affects cattle herds, causing economic losses due to reproductive problems which require expensive treatments. The main source of transmission for cattle is still uncertain, but rodents and bats can play an important role in the transmission cycle by being maintenance hosts for the pathogenic species of the bacterium and spreading it through urine. In this study, we characterize possible risk areas for bovine leptospirosis exposure in the state of Veracruz, Mexico, based on the geographical distribution of flying (bats) and terrestrial (rodents and opossums) wild hosts of Leptospira sp. reported in Mexico, in addition to climate, geography, soil characteristics, land use and human activities (environmental variables). We used a generalized linear regression model to understand the association between the frequency of anti-Leptospira sp. antibodies (a proxy of exposure) in cattle herds exposed to Leptospira, the favourability of wild hosts of Leptospira as well as the environmental variables. The parameterized model explained 12.3% of the variance. The frequency of anti-Leptospira sp. antibodies exposure in cattle herds was associated with elevation, geographic longitude, pH of the soil surface and environmental favourability for the presence of rodents, opossums and bats. The variation in exposure was mainly explained by a longitudinal gradient (6.4% of the variance) and the favourability-based indices for wild hosts (9.6% of the variance). Describing the possible risks for exposure to Leptospira in an important and neglected livestock geographical region, we provide valuable information for the selection of areas for diagnosis and prevention of this relevant disease.

Original Leptospira spp. in island native terrestrial mammals: a case study in Pteropus spp. bats of New Caledonia

Leptospirosis is a bacterial zoonosis that occurs in tropical and subtropical regions worldwide. Chiroptera are known to be a formidable reservoir of zoonotic pathogens, including leptospires. The epidemiology of leptospirosis in bats in the Pacific Islands is poorly known, both in terms of prevalence and in terms of the bacterial strains involved. A strong host specificity between leptospiral strains and their mammalian reservoir is recognized. This phenomenon has notably been studied recently in bat communities, providing strong evidence of coevolution. In New Caledonia, a biodiversity hotspot where leptospirosis is endemic and enzootic, Chiroptera are the only indigenous terrestrial mammals. In this study, we aimed to investigate leptospires associated with three flying fox species in New Caledonia. Kidneys and urine samples of Pteropus spp. from captures and seizures were analyzed. Among 254 flying foxes analyzed, 24 harboured pathogenic leptospires corresponding to an observed prevalence of 9.45% with 15.8% on the Main Island and 4.3% on Loyalty Islands. The analysis of the rrs gene, lfb1, MLST sequences evidenced 4 distinct clusters of undescribed strains, likely corresponding to undescribed species. All four strains belong to the Group I of pathogenic Leptospira spp., which includes Leptospira interrogans, Leptospira noguchii and Leptospira kirschneri. We detected pathogenic leptospires in all 3 Pteropus spp. studied (including 2 endemic species) with no evidence of host specificity in two co-roosting species. For a better understanding of Leptospira-host coevolution, notably to genetically characterize and evaluate the virulence of these original bat-associated leptospires, it is essential to improve isolation techniques. Flying foxes are traditionally hunted and eaten in New Caledonia, a massive cause of bat-human interactions. Our results should encourage vigilance during these contacts to limit the spillover risk of these pathogens to humans. This article is protected by copyright. All rights reserved.

Leptospira sp. infection in bats: A systematic review and meta-analysis

Bats are the only flying mammalian animals and are distributed worldwide. Bats are well-known hosts of several zoonotic viruses and bacteria, including Leptospira sp. Here, we performed a systematic review and a meta-analysis of evidence of Leptospira sp. infection in bats by examining studies published between 1964 and 2021. We reported the frequencies of various species and serogroups on all continents, several species and feeding habits of bats, and different diagnostic tools. Together, 33 papers from all continents with seven to 2077 individuals from one to 31 species were included. Molecular detection was conducted in most studies, followed by MAT (Microscopic Agglutination Test) and isolation and identification. Molecular characterization of Leptospira sp. revealed L. borgpetersenii as the most frequent species. Moreover, 179 positive samples for MAT contained the most likely infecting serogroups described, particularly the Australis serogroup. The percentage of positive tests in isolation and identification ranged between zero and 0.5%. The highest frequency of Leptospira infection among the continents was observed in Asia, whereas South America had the lowest percentage. Finally, Nycteridae and Rhinonycteridae were the most frequently infected bat families. Our study provides valuable information about the epidemiology of Leptospira sp. infection in bats. This article is protected by copyright. All rights reserved.

Leptospira noguchii associated to reproductive disease in ruminants

Leptospirosis is known to determine reproductive disorders on livestock, and Leptospira interrogans and Leptospira borgpetersenii are the most frequently reported species. Leptospira noguchii is an emerging pathogen, but its association with reproductive disease is unclear. We have detected L. noguchii as the agent of an outbreak with reproductive disorders in a Brazilian dairy goat flock. In the kidding season, five out of 10 Saanen had abortions in the final month of pregnancy and two newborn kids had acute clinical signs. After necropsy of three foetuses and one newborn kid, fragments of liver, lung and kidney were submitted to lipL32-PCR. It yielded positive results in at least one fragment from each animal. After, a nested secY-PCR, followed by sequencing, could identify L. noguchii, with 99-100% of identity with sequences obtained from cattle in the same region. For the first time, L. noguchii was detected in goats and, most importantly, the association of this leptospiral species with reproductive failures in ruminants has been demonstrated.

Persistent High Leptospiral Shedding by Asymptomatic Dogs in Endemic Areas Triggers a Serious Public Health Concern

Simple Summary

Dogs are known as hosts of Leptospira interrogans and can spread this bacterium to the environment. Although Canicola is responsible for determining chronic disease in dogs, when affected by incidental serogroups such as Icterohaemorrhagiae, acute disease may occur with a predominance of clinical signs with hepatic and renal lesions. In endemic areas, it is a serious public health problem, as dogs can become asymptomatic carriers of leptospires in the urine, characterizing a risk in the context of zoonotic leptospirosis. Thus, this study aims to estimate the incidence and duration of the elimination of leptospires in the urine of dogs, taking another step from a previous study of our group, by a longitudinal, long-term and molecular approach. A total of 125 dogs without signs of leptospirosis were included in the study. Of the 125 dogs, 62 were PCR-positive (48.8% (95% CI, 47.9–49.7%)) throughout the study. Most dogs were shedding the Icterohaemorrhagiae serogroup in urine, which was unexpected, since the animals remained clinically asymptomatic during the study. Although the fact that asymptomatic dogs eliminate leptospires is not new, the extent of this fact and that the strain is virulent is impressive, with an impact on public health that cannot be overlooked.

Abstract

(1) Background: Dogs are known as hosts of Leptospira interrogans and can spread this bacterium to the environment. Although Canicola is responsible for determining chronic disease in dogs, when affected by incidental serogroups such as Icterohaemorrhagiae, acute disease may occur with a predominance of clinical signs with hepatic and renal changes. In endemic areas, it is a serious public health problem. Thus, this study aims to estimate the incidence and duration of elimination of leptospires in the urine of dogs, taking another step from a previous study of our group, by a longitudinal, long-term and molecular approach. (2) Methods: A total of 125 dogs without apparent symptoms of leptospirosis were included in the study. The dogs were all PCR-negative and seronegative at the beginning of the study. Blood samples were collected for hematological examinations and urine for amplification of the lipL32 gene by PCR at five different time points during one year. (3) Results: Out of the 125 dogs, 62 became lipL32 PCR-positive (48.8% (95% CI, 47.9–49.7%)) at some point during the study, distributed as follows: at day 0, all negative; day 90, 18/125 (14.4% (95% CI, 13.5–15.3%)); day 180, 18/125 (14.4% (95% CI, 13.5–15.3%)); day 270, 12/125 (9.6% (95% CI, 8.7–10.5%)); and day 365, 14/125 (11.2% (95% CI, 10.3–12.1%)). Out of the 62 amplicons, 22 were sequenced, targeting a short region of secY gene. Of these, 20 (90.9%) were identical to the L. interrogans serovar Icterohaemorrhagiae, while two (9.1%) were Leptospira noguchii. (4) Conclusions: The fact that the leptospires of the Icterohaemorrhagiae serogroup were characterized was unexpected, since the animals remained clinically asymptomatic during the study. The fact that asymptomatic dogs shed leptospires is not new, but the extent of this fact and the characterized strain is impressive, with an impact on public health that cannot be overlooked.

Urinary shedding of leptospires in palearctic bats

Leptospirosis is a bacterial zoonotic infection of worldwide occurrence. Bats, like other mammalian reservoirs, may be long-term carriers that maintain endemicity of infection and shed viable leptospires in urine. Direct and/or indirect contact with these Leptospira shedders is the main risk factor as regards public health concern. However, knowledge about bat leptospirosis in the Palearctic Region, and in Europe in particular, is poor. We collected urine from 176 specimens of 11 bat species in the Czech Republic, Poland, Republic of Armenia and the Altai Region of Russia between 2014 and 2019. We extracted DNA from the urine samples to detect Leptospira spp. shedders using PCR amplification of the 16S rRNA and LipL32 genes. Four bat species (Barbastella barbastellus n = 1, Myotis bechsteinii n = 1, Myotis myotis n = 24 and Myotis nattereri n = 1) tested positive for Leptospira spp., with detected amplicons showing 100% genetic identity with pathogenic Leptospira interrogans. The site- and species-specific prevalence range was 0%-24.1% and 0%-20%, respectively. All bats sampled in the Republic of Armenia and Russia were negative. Given the circulation of pathogenic leptospires in strictly protected Palearctic bat species and their populations, non-invasive and non-lethal sampling of urine for molecular Leptospira spp. detection is recommended as a suitable surveillance and monitoring strategy. Moreover, our results should raise awareness of this potential disease risk among health professionals, veterinarians, chiropterologists and wildlife rescue workers handling bats, as well as speleologists and persons cleaning premises following bat infestation.

First report of pathogenic Leptospira spp. in Tadarida brasiliensis bats (family Molossidae) and Eptesicus furinalis (family Vespertilionidae) of Argentina. New host species in this country?

Leptospirosis is an endemic disease caused by Leptospira spp., a bacterium that affects animals and humans. In recent years, the number of reports of leptospirosis in wild animals has increased, which highlights the need to study the infectious agents in these animals. In this study, a duplex PCR for the detection of leptospiral DNA was performed on 50 kidney samples from bats, and a MAT (Microscopic Agglutination Test) for serological detection of anti-leptospiral antibodies was applied to 47 serum samples from bats from different regions of Buenos Aires Province, Argentina. DNA was extracted using Chelex-100 and duplex PCR was performed by targeting the detection of genes secY and flaB, of pathogenic Leptospira spp. Of the 50 kidney samples, 3 were positive for Eumops sp. and Tadarida brasiliensis by duplex PCR. Of the 47 serum samples, 12 were positive for different serovars: Leptospira interrogans serovars Icterohaemorrhagiae, Cynopteri and Bataviae, and Leptospira borgpetersenii serovar Ballum. This is the first report of the detection of pathogenic leptospires by serology in bats belonging to the T. brasiliensis and Eptesicus furinalis species in Argentina. In addition, this is the first report of the detection of pathogenic leptospiral DNA by PCR in T. brasiliensis species. The detection of Leptospira spp. in these wild animals shows that they may play an important role as wildlife reservoirs of leptospires.

Insight into the Epidemiology of Leptospirosis: A Review of Leptospira Isolations from "Unconventional" Hosts

Leptospirosis is a re-emerging worldwide zoonotic disease. Even though the primary serological test for diagnosis and surveying is the microscopic agglutination test (MAT), isolation remains the gold-standard test to detect Leptospira infections. The leptospirosis transmission is linked to maintenance and accidental hosts. In the epidemiology of Leptospira some serovar are strictly related to specific maintenance hosts; however, in recent years, the bacterium was isolated from an even wider spectrum of species. The aim of this review is to report the isolation of Leptospira strains in animals which could be recognized as "unconventional" hosts, analyzing studies from 1960 to 2020 that highlighted the Leptospira isolation. This scientific literature aimed to provide evidence of infection in several animal species including of the Carnivora, Didelphimorphia, Rodentia, Cetacea, Cingulata, Afrosoricida, Chiroptera and Primate orders, as well as in Reptilia and Amphibia classes. In conclusion, the spreading of Leptospira is attention-worthy because the infection could occur in all the animal species ranging in a specific area. Further screening and isolations are needed to collect all necessary data to gain a complete understanding of leptospirosis epidemiology and its modifications.

Molecular and Serological Prevalence of Leptospira spp. in Feral Pigs (Sus scrofa) and their Habitats in Alabama, USA

Leptospirosis is a widespread zoonosis and has been recognized as a re-emerging infectious disease in humans and a variety of wild and domestic animal species. In order to understand the prevalence and diversity of Leptospira spp. in feral pig populations of Alabama, we trapped 315 feral pigs in Bullock County east-central Alabama, and collected 97 environmental samples from riparian areas in Bullock County and Macon County east-central Alabama. Two previously published PCRs followed by DNA sequencing and BLASTn were performed to identify pathogenic Leptospira species in the kidney of feral pigs (3.2%, 10/315) as well as environmental samples collected from the habitats of feral pigs (2.1%, 2/97), but not in the whole blood samples (n = 276) or spleen (n = 51). An ELISA determined that 44.2% of serum samples (122/276) were antibody-positive for Leptospira. The identification of two pathogenic Leptospira species from environmental samples and the high sero-positivity in feral pigs suggests potential pathogen shedding from feral pigs to environments, and to humans and domestic animals. In order to better understand the risk to human health associated with feral swine presence, further studies are warranted to explore the interrelationship between Leptospira spp. shedding in the urine of feral pigs and bacterial culture to explore pathogenicity. Multi-locus sequencing typing (MLST) and microscopic agglutination tests (MAT) should be performed in future studies to make a definite determination of pathogenic Leptospira in feral pigs in Alabama.

SEROLOGIC SURVEY OF LEPTOSPIRA SPP. IN CAPTIVE ANIMALS FROM VERACRUZ, MEXICO

Leptospirosis is the most common zoonotic disease worldwide and is considered endemic in countries with tropical climates. It is caused by 10 species of the Leptospira genus and by more than 275 serovars which can affect a wide range of vertebrates. In the Americas, 122 species of four classes of vertebrates have been reported to be infected or exposed to many Leptospira species. Many of these reports are from zoos and rehabilitation centers. Mexico has one single study that reported antibody titers against Leptospira in zoo animals. The purpose of this research was to identify the degree of exposure of some captive mammals and reptiles in Veracruz, a Mexican state with endemic leptospirosis, through microagglutination using 14 live strains of five Leptospira species. Sera samples were collected from 55 animals of 11 species from two classes (Mammalia and Reptilia), four orders (Primates, Artiodactyla, Carnivora, Crocodilia), and nine genera. The more prevalent serovars were Icterohaemorrhagiae and Tarassovi and the highest titers were reactive to the serovar Icterohaemorrhagiae with a value of 1: 51,200.

Pathogenic Leptospira and their animal reservoirs: testing host specificity through experimental infection

Leptospirosis is caused by pathogenic Leptospira transmitted through contact with contaminated environments. Most mammalian species are infectable by Leptospira but only few act as efficient reservoir being capable of establishing long term kidney colonization and shedding Leptospira in urine. In Madagascar, a large diversity of pathogenic Leptospira display a tight specificity towards their endemic volant or terrestrial mammalian hosts. The basis of this specificity is unknown: it may indicate some genetically determined compatibility between host cells and bacteria or only reflect ecological constraints preventing contacts between specific hosts. In this study, Rattus norvegicus was experimentally infected with either Leptospira interrogans, Leptospira borgpetersenii or Leptospira mayottensis isolated from rats, bats or tenrecs, respectively. Leptospira borgpetersenii and L. mayottensis do not support renal colonization as featured by no shedding of live bacteria in urine and low level and sporadic detection of Leptospira DNA in kidneys. In contrast 2 out of the 7 R. norvegicus challenged with L. interrogans developed renal colonization and intense Leptospira shedding in urine throughout the 3 months of experimental infection. These data suggest that host-Leptospira specificity in this biodiversity hotspot is driven at least in part by genetic determinants likely resulting from long-term co-diversification processes.

Molecular detection of Bartonella, Ehrlichia and Mycoplasma in feral dogs of El Pedregal de San Angel Ecological Reserve in Mexico City

Free-ranging and feral dogs represent a group of unattended companion animals. They impact wild animal populations by predating native species, displacing predators and introducing exotic pathogens. The aim of this work was to describe the molecular occurrence of Rickettsia, Ehrlichia, Anaplasma, Mycoplasma and Bartonella in feral dogs. The study was carried out in the last relict of a protected area in Mexico City. Blood clots samples from 19 dogs were obtained and analyzed for detection of specific fragments of the 16S-rRNA gene for Anaplasma, Ehrlichia and Mycoplasma and citrate synthase (gltA) for Bartonella and Rickettsia. Our results showed that DNA from three bacteria species (Bartonella vinsonii subsp. berkhoffii, Ehrlichia canis and Mycoplasma haemocanis) was present with frequencies ranging from 5.3 to 15.8%. This is the first record of B. vinsonii subsp. berkhoffii and M. haemocanis in dogs from México, and also the first finding of Ehrlichia canis in Mexico City. It is important to perform surveillance of feral dog populations in order to identify the impact of these pathogens on wild animal populations and Public Health in order to establish prevention and protection programs.

Phylogenetic relationships and diversity of bat-associated Leptospira and the histopathological evaluation of these infections in bats from Grenada, West Indies

Bats can harbor zoonotic pathogens, but their status as reservoir hosts for Leptospira bacteria is unclear. During 2015-2017, kidneys from 47 of 173 bats captured in Grenada, West Indies, tested PCR-positive for Leptospira. Sequence analysis of the Leptospira rpoB gene from 31 of the positive samples showed 87-91% similarity to known Leptospira species. Pairwise and phylogenetic analysis of sequences indicate that bats from Grenada harbor as many as eight undescribed Leptospira genotypes that are most similar to known pathogenic Leptospira, including known zoonotic serovars. Warthin-Starry staining revealed leptospiral organisms colonizing the renal tubules in 70% of the PCR-positive bats examined. Mild inflammatory lesions in liver and kidney observed in some bats were not significantly correlated with renal Leptospira PCR-positivity. Our findings suggest that Grenada bats are asymptomatically infected with novel and diverse Leptospira genotypes phylogenetically related to known pathogenic strains, supporting the hypothesis that bats may be reservoirs for zoonotic Leptospira.

Leptospirosis trends in China, 2007-2018: A retrospective observational study

Leptospirosis is one of the most common and neglected tropical waterborne diseases in China, causing serious economic losses, and constituting a significant public health threat. Leptospirosis has recently received increased attention and is considered a re-emerging infectious disease in many countries. The incidence of leptospirosis among people suggests that occupation, age, season, sex and water recreational activities are significant risk factors. The aim of this study was to describe the epidemiological profiles of leptospirosis in China during the 2007-2018 period. The morbidity data of leptospirosis by age, season (month), gender, occupation and geographic location (different provinces) were obtained from the public health science data centre of China for subsequent epidemiological analysis. The results indicate that the incidence of leptospirosis has shown a slow downward trend from 2007 to 2018, but morbidity rates were still relatively high (0.0660-0.0113). The incidence of leptospirosis varied in different provinces of China; cases localized mainly to the Southern and Central provinces, areas with warm weather and ample rainfall. Older people (aged 60-75), males, farmers, students and field workers were high-risk populations. During the 2007-2018 observation period, morbidity rates increased beginning in May, remained at high levels in August and September and decreased after November. The present investigation highlights the re-emergence of leptospirosis in some provinces of China (especially in Yunnan and Fujian) and shows that leptospirosis remains a serious public health threat. The results of this study should enhance measures taken for the prevention, control, and surveillance of leptospirosis in China.

Molecular epidemiology of Leptospira noguchii reveals important insights into a One Health context

Leptospirosis presents a complex and dynamic epidemiology. Bovine leptospirosis has been described as a major infectious disease impairing reproductive efficiency. Although infections by Leptospira interrogans, L. santarosai and L. borgpetersenii are frequently reported in cattle, the presence of L. noguchii in these animals should not be neglected. In this study, we describe serological (MAT) and molecular characterization (rrs and secY gene sequencing, multilocus sequence typing [MLST] and pulsed-field gel electrophoresis [PFGE]) of eight L. noguchii strains obtained from slaughtered cows. Intraspecific genetic diversity was evaluated, and haplotype networks were constructed based on hosts and geographical localizations. Strains were characterized as belonging to serogroups Australis, Autumnalis and Panama, and molecular characterization showed a high heterogeneity of these strains. Ten different STs were found (including nine new STs and 39 novel alleles) as well as nine different pulsotypes. Two clonal complexes were found. Phylogenetic trees based on secY locus and concatenated MLST loci showed two main clusters, with sequences from the present study included in the first. In general, there was no relationship between the geographical origin and the secY phylogenetic clusters, as well as between secY phylogenetic clusters and serogroups. Molecular diversity indexes confirmed a high variability (H > 0.8). This high intraspecific variation observed may be related to differences in virulence, pathogenicity and antigenicity or even adaptability of the strains. In addition, haplotype networks clearly demonstrated the circulation of genotypes between humans and animals, confirming the zoonotic potential. The present study provides relevant data for the study of leptospirosis in the One Health context, where human, animal and environmental health is closely connected.

Isolation and characterization of trypanosomatids, including Crithidia mellificae, in bats from the Atlantic Forest of Rio de Janeiro, Brazil

We studied infection by Trypanosomatidae in bats captured in two areas with different degradation levels in the Atlantic Forest of Rio de Janeiro state: Reserva Ecológica de Guapiaçu (REGUA) and Estação Fiocruz Mata Atlântica (EFMA). Furthermore, we evaluated whether the diversity of trypanosomatids changes according to bat diversity and the different levels of preservation in the region. The results showed no influence of the level of preservation on bat species richness (15 and 14 species, respectively), with similar chiropterofauna and higher abundance of two common fruit-eating bat species in the tropics: Carollia perspicillata and Artibeus lituratus. Of the 181 bat specimens analyzed by LIT/Schneider hemoculture, we detected 24 infected individuals (13%), including one positive Sturnira lilium individual that was also positive by fresh blood examination. Molecular characterization using nested PCR targeting the 18 SSU rRNA-encoding gene fragment showed similar trypanosomatid infection rates in bats from the two areas: 15% in REGUA and 11% in EFMA (p = 0.46). Trypanosoma dionisii was the most frequently detected parasite (54%), followed by T. cruzi DTUs TcI and TcIV and Trypanosoma sp., in Neotropical phyllostomid bats (RNMO63 and RNMO56); mixed infections by T. dionisii/T. cruzi TcIII and T. dionisii/T. cruzi TcI were also observed. The T. cruzi DTUs TcI and TcIV are the genotypes currently involved in cases of acute Chagas disease in Brazil, and T. dionisii was recently found in the heart tissue of an infected child. Surprisingly, we also describe for the first time Crithidia mellificae, a putative monoxenous parasite from insects, infecting a vertebrate host in the Americas. Bats from the Atlantic Forest of Rio de Janeiro state harbor a great diversity of trypanosomatids, maintaining trypanosomatid diversity in this sylvatic environment.

Epidemiological study of ticks collected from the northern tamandua (Tamandua mexicana) and a literature review of ticks of Myrmecophagidae anteaters

The family Myrmecophagidae contains three anteater species: Tamandua mexicana (Saussure, 1860), Tamandua tetradactyla (Linnaeus, 1758) and Myrmecophaga tridactyla (Linnaeus, 1758). These American anteater species currently face many conservation threats, among which road traffic accidents stand out. Parasitic studies on this family are scarce, and some of them include records of ectoparasites. Specifically for northern tamandua (T. mexicana), there is a lack of studies at population level. The objectives of the present research were to carry out an epidemiological study of tick species and its abundance on road-killed northern anteater specimens and, moreover, to perform a literature review of ticks collected from anteaters of Myrmecophagidae family. Five tick species were identified, including four Amblyomma spp. and Rhipicephalus sanguineus sensu lato, on 23 road-killed anteaters. Tick infestation prevalence was 43% (10/23), with a median tick infestation intensity of 3.5 per anteater (interquartile range 1-13.7). The bibliographic review highlighted the existence of twenty-nine ixodid species recorded on the three anteater species from 14 countries, mainly Brazil. The most common tick species on the Myrmecophagidae family are Amblyomma nodosum, A. calcaratum, A. cajennense sensu lato and A. auricularium. Some of these ixodids were also described as vectors of pathogens. Further studies are needed to evaluate the impact of ticks on anteater fitness, and to assess the role of these mammals as reservoirs of vector-borne diseases.

Genetic structure analysis of Amblyomma mixtum populations in Veracruz State, Mexico

Amblyomma mixtum Koch, 1844 parasitizes livestock, humans, and wildlife in Mexico. However, information on population genetics for this tick species in the country is missing. Tick samples were collected from livestock in ten regions across the state of Veracruz (22°28'N, 17°09'S, 93°36'E, 98°39'W) to analyze the genetic structure of   A. mixtum populations. Ticks were morphologically identified using taxonomic keys. In order to test the intra-specific variability of A. mixtum fragments of the mitochondrial gene 16S-rRNA and cytochrome oxidase subunit 1 (COI) were amplified. Ninety-six sequences were amplified from the 50 specimens' analyzed (96% amplification success). Eleven haplotypes were detected in 16S-rRNA gene and 10 more for COI. Neutrality tests showed negative results in most of the locations analyzed, which is indicative of an excess of recently derived haplotypes. However, these results were not statistically significant. Minimal union network analysis revealed that there is no separation of populations by geography, and that there is an overlap of several haplotypes among diverse populations. Significant genetic differentiation was not detected in the A. mixtum populations sampled in the state of Veracruz, Mexico, this may be due to the frequent movement of livestock hosts. This is the first report on the genetic structure of A. mixtum populations in Mexico.