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

Molecular detection and characterization of Leptospira species in bats and other small wild mammals from Villeta municipality, Colombia

Leptospira is a bacterial genus which includes several pathogenic species. Wild mammals can act as reservoir hosts, shedding bacteria in their urine. Leptospirosis is an important health problem in Villeta, but data regarding potential reservoirs hosts and natural sources of infection are still scarce. We aimed to detect and characterize the presence of Leptospira among small wild mammals from Villeta municipality, Colombia. Small wild mammals from three orders: Didelphimorphia, Chiroptera and Rodentia, were sampled in the region. DNA was extracted from kidney samples and screened for Leptospira through real-time PCR targeting a the 16 s rRNA gene. Positive samples were screened through conventional PCR using five complementary genes: adk, icdA, lipL32, lipL41 and secY. Amplicons were sequenced and used for phylogenetic analysis. A total of 75 kidney samples were collected from three small wild mammal orders: 62 bats, 5 opossums, and 7 rodents. Leptospira spp. was detected in 38.7 % of the samples, with bats presenting the most frequent infection rate (43.5 %). The infection rate varied by sampling site, with the highest frequency observed in Mave village (57.1 %). Concatenated phylogenetic analysis revealed that all sequences clustered within the P1/Pathogenic Leptospira major clade, forming three subclades: two bat-related Leptospira subclades, and one subclade including Leptospira interrogans, Leptospira kirschneri, and Leptospira noguchii species. This study describes the presence of Leptospira among bats and opossums from Villeta, Colombia. It also identifies the circulation of several P1/pathogenic Leptospira species among bats forming three clusters, two of them composed exclusively of bat-related leptospires, and one together with recognized pathogenic species.

Genetic diversity of pathogenic Leptospira spp. harbored by bats in Japan

Leptospirosis is a zoonotic infectious disease caused by pathogenic Leptospira species. In Japan, human and canine leptospirosis cases are reported annually. Although wild animals, including bats, are known to harbor pathogenic Leptospira spp., infection of bats in this region has never been explored. This study aimed to determine the presence of leptospires and their genetic diversity in five Japanese bat species. Kidney tissue and blood samples were collected from 115 bats captured in the Yamaguchi Prefecture and Hokkaido, Japan. Pathogenic Leptospira spp. were detected in the kidneys by real-time PCR and conventional PCR using primers targeting lipL32 and rrs2. Multilocus sequence typing (MLST) and sequencing of secY gene were performed on PCR-positive DNA samples. Leptospira spp. were detected in 26 of the 115 bats (22.6 %), including Rhinolophus ferrumequinum (5/37, 14 %), Rhinolophus cornutus (2/6, 33 %), Miniopterus schreibersii (6/37, 16 %), Myotis macrodactylus (11/15, 73 %), and Vespertilio sinensis (2/20, 10 %). Phylogenetic analysis based on MLST genes and secY gene revealed detected genes clustered with either L. interrogans, L. borgpetersenii, or L. kirschneri and a relationship between the leptospires identified in the bats in this study and bats in other countries or other host, and PCR with L. borgpetersenii-specific primers revealed co-infection with multiple Leptospira species in individual bats. Our study demonstrated a high carriage rate, genetic diversity of Leptospira spp., and co-infection with multiple Leptospira spp. in Japanese bats.

In search of pathogenic Leptospira species in Myotis and other vesper bats, Russia

Various bat species worldwide have been identified as Leptospira carriers, especially in tropical regions. In this study, we investigated the infection of Vespertilionidae bats by pathogenic Leptospira in north-west Russia. Out of 264 bats from 13 species, the urine of 24 specimens tested positive according to a polymerase chain reaction test. The infected species were exclusively Myotis bats: M. brandtii (1/56; 1.8 %); M. dasycneme (9/40; 22.5 %); and M. daubentonii (14/47; 29.8 %). The detected Leptospira strains were similar to L. kirschneri and L. borgpetersenii.

Serological and molecular investigation of Leptospira spp. In bats (Chiroptera, Mammalia) from Brazil

Bats play a crucial role in the ecosystem, yet concerns have arisen regarding their potential as carriers of zoonotic bacteria, including Leptospira spp. Due to the lack of knowledge about the carrier state of bats in Brazil, this study aimed to evaluate the presence of antibodies against Leptospira spp. and its DNA in bats from four Brazilian States (São Paulo, Paraíba, Pernambuco, and Ceará). Bats were captured using mist nets and categorized by sex, age, and species. Antibodies were searched in 22 bats via the microscopic agglutination test (MAT). Additionally, 168 kidney and nine urine samples were subjected to PCR for Leptospira spp. Out of 177 samples tested, two (1.13 %) were positive in PCR, while none showed reactivity in MAT. These results suggest a low prevalence of Leptospira spp. infection in bats, indicating a limited role in transmitting leptospirosis to humans, domestic animals, and wildlife in the studied region.

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.

Genetic diversity of P1/pathogenic Leptospira species hosted by bats worldwide

INTRODUCTION

Bats are a diverse group of mammals that have unique features allowing them to act as reservoir hosts for several zoonotic pathogens such as Leptospira. Leptospires have been classified into pathogenic, intermediate, and saprophytic groups and more recently into clades P1, P2, S1, and S2, being all the most important pathogenic species related to leptospirosis included within the P1/pathogenic clade. Leptospira has been detected from bats in several regions worldwide; however, the diversity of leptospires harboured by bats is still unknown.

AIM

The aim of the present study was to determine the genetic diversity of Leptospira spp. harboured by bats worldwide.

METHODS

A systematic review was conducted on four databases to retrieve studies in which Leptospira was detected from bats. All studies were screened to retrieve all available Leptospira spp. 16S rRNA sequences from the GenBank database and data regarding their origin. Sequences obtained were compared with each other and reference sequences of Leptospira species and analysed through phylogenetic analysis.

RESULTS

A total of 418 Leptospira spp. 16S rRNA sequences isolated from 55 bat species from 14 countries were retrieved from 15 selected manuscripts. From these, 417 sequences clustered within the P1/pathogenic group, and only one sequence clustered within the P2/intermediate group. Six major clades of P1/pathogenic Leptospira spp. were identified, three of them composed exclusively of sequences obtained from bats.

CONCLUSION

We identified that bats harbour a great genetic diversity of Leptospira spp. that form part of the P1/pathogenic clade, some of which are closely related to leptospirosis-associated species. This finding contributes to the knowledge of the diversity of leptospires hosted by bats worldwide and reinforces the role of bats as reservoirs of P1/pathogenic Leptospira spp.

Global distribution of Leptospira serovar isolations and detections from animal host species: A systematic review and online database

OBJECTIVES

Leptospira, the spirochaete causing leptospirosis, can be classified into >250 antigenically distinct serovars. Although knowledge of the animal host species and geographic distribution of Leptospira serovars is critical to understand the human and animal epidemiology of leptospirosis, current data are fragmented. We aimed to systematically review, the literature on animal host species and geographic distribution of Leptospira serovars to examine associations between serovars with animal host species and regions and to identify geographic regions in need of study.

METHODS

Nine library databases were searched from inception through 9 March 2023 using keywords including Leptospira, animal, and a list of serovars. We sought reports of detection of Leptospira, from any animal, characterised by cross agglutinin absorption test, monoclonal antibody typing, serum factor analysis, or pulsed-field gel electrophoresis to identify the serovar.

RESULTS

We included 409 reports, published from 1927 through 2022, yielding data on 154 Leptospira serovars. The reports included data from 66 (26.5%) of 249 countries. Detections were from 144 animal host species including 135 (93.8%) from the class Mammalia, 5 (3.5%) from Amphibia, 3 (2.1%) from Reptilia, and 1 (0.7%) from Arachnida. Across the animal host species, Leptospira serovars that were detected in the largest number of animal species included Grippotyphosa (n = 39), Icterohaemorrhagiae (n = 29), Pomona (n = 28), Australis (n = 25), and Ballum (n = 25). Of serovars, 76 were detected in a single animal host species. We created an online database to identify animal host species for each serovar by country.

CONCLUSIONS

We found that many countries have few or no Leptospira serovars detected from animal host species and that many serovars were detected from a single animal species. Our study highlights the importance of efforts to identify animal host species of leptospirosis, especially in places with a high incidence of human leptospirosis. We provide an updated resource for leptospirosis researchers.

Bat-Associated Pathogenic Leptospira spp. from Forest Fragments in Southwestern Brazilian Amazonia

Bats are known as potential carriers of different pathogens; these animals have been identified worldwide as an important reservoir of different species of Leptospira. Therefore, there has been an increasing interest in studying leptospirosis in neotropical bats in the Amazon. This region is a fertile ground for zoonotic diseases, given the intense process of deforestation, urbanization, opening of new agricultural frontiers, predatory hunting, effects of climate change, and loss of biodiversity. Based on this, the aim of the present study was to investigate the frequency of infection associated with the genetic characterization of pathogenic Leptospira spp. in bats inhabiting diverse landscapes in the southwestern region of the Amazon. To conduct the study, mist nets were installed to capture bats. Kidney samples were submitted to LipL32-polymerase chain reaction and secY gene sequencing. Our results showed that 21% of neotropical evaluated bats in Southwestern Amazon were infected with Leptospira spp. Positive animals were found in rural, urban, periurban, and control areas. Sanguinivores had the highest frequency of positives, followed by insectivores and frugivorous bats. The species of L. interrogans and a potential new Leptospira species were identified. The frequency of Leptospira in bats was not influenced by landscape type, suggesting these pathogens may not be affected by landscape changes. The findings suggest that bats may serve as potential reservoirs of Leptospira in diverse landscapes. The presence of Leptospira in bats appears to be independent of the type of land use, implying that these pathogens may not be affected by small-scale changes in the environment.

Bats (Mammalia: Chiroptera) in urban-rural interfaces: community structure associated with pathogen screening in São Paulo-the largest metropolitan region in Brazil

Little is known about the influence of the urban environments on bat species 'ecology. The urbanization process potentially lead to critical ecological changes in bat communities' intra and interspecific pathogenic transmissions dynamics. To date, the monitoring of pathogens in bats in Brazil has only been done with bats found dead or alive in households, from rabies surveillance systems. The present work aimed to investigate how urbanization influenced bat richness, relative abundance and pathogen occurrence. Most captured bats were Phyllostomidae, especially Sturnira lilium, Artibeus lituratus, A. fimbriatus, Glossophaga soricina, and Platyrrhinus lineatus, among others. From preserved-rural towards urban areas the lesser the bat richness, the higher the relative abundance of the captured bats. Noise level, luminosity and relative humidity correlated with bat abundance. The proportion of genders, sexually active bats and their size (weight, right forearm length, and body condition index) were stable throughout the investigation. Still, the proportion of pregnant females was higher in Spring and the number of juveniles in Summer, evidencing the seasonality of reproduction. Several Enterobacteria were isolated, evidencing a significant role of bats in the circulation of pathogens of medical and veterinary interest. These results are crucial in the pursuit of a harmonious coexistence between humans, bats and domestic animals in areas with different levels of anthropization.

Trends in Bacterial Pathogens of Bats: Global Distribution and Knowledge Gaps

Bats have received considerable recent attention for infectious disease research because of their potential to host and transmit viruses, including Ebola, Hendra, Nipah, and multiple coronaviruses. These pathogens are occasionally transmitted from bats to wildlife, livestock, and to humans, directly or through other bridging (intermediate) hosts. Due to their public health relevance, zoonotic viruses are a primary focus of research attention. In contrast, other emerging pathogens of bats, such as bacteria, are vastly understudied despite their ubiquity and diversity. Here, we describe the currently known host ranges and geographic distributional patterns of potentially zoonotic bacterial genera in bats, using published presence-absence data of pathogen occurrence. We identify apparent gaps in our understanding of the distribution of these pathogens on a global scale. The most frequently detected bacterial genera in bats are Bartonella, Leptospira, and Mycoplasma. However, a wide variety of other potentially zoonotic bacterial genera are also occasionally found in bats, such as Anaplasma, Brucella, Borrelia, Coxiella, Ehrlichia, Francisella, Neorickettsia, and Rickettsia. The bat families Phyllostomidae, Vespertilionidae, and Pteropodidae are most frequently reported as hosts of bacterial pathogens; however, the presence of at least one bacterial genus was confirmed in all 15 bat families tested. On a spatial scale, molecular diagnostics of samples from 58 countries and four overseas departments and island states (French Guiana, Mayotte, New Caledonia, and Réunion Island) reported testing for at least one bacterial pathogen in bats. We also identified geographical areas that have been mostly neglected during bacterial pathogen research in bats, such as the Afrotropical region and Southern Asia. Current knowledge on the distribution of potentially zoonotic bacterial genera in bats is strongly biased by research effort towards certain taxonomic groups and geographic regions. Identifying these biases can guide future surveillance efforts, contributing to a better understanding of the ecoepidemiology of zoonotic pathogens in bats.