Leishmania presence in bats in areas endemic for leishmaniasis in central-west Brazil

The relationships among Leishmania infantum and phyllostomid bats assessed by histopathological and molecular assays

Bats have been reported as reservoir host of Leishmania spp. worldwide, mostly by molecular detection. However, it is still unclear whether bats act as reservoirs of Leishmania infantum to sandflies vectors. In this sense, the investigation of amastigotes forms in the target organs, and the characterization of their associated inflammation, may help to clarify the epidemiological importance of bats in endemic areas for leishmaniasis. The aim of this work was to investigate the host-parasite relationships under microscopic evaluation and predict the epidemiological role of two phyllostomid bats species naturally infected by L. infantum in an endemic area for human leishmaniasis. Fragments of skin, liver and spleen of L. infantum positive and negative bats (Artibeus planirostris and Carollia perspicillata) by qPCR, were studied by histological and immunohistochemical techniques. Both groups, positive and negative, did not show differences in the histopathological study, presenting only discrete tissue changes. Liver and skin showed mild inflammatory reactions. Findings on spleen consisted of reactivity of the lymphoid follicles, expressive presence of apoptotic cells and macrophages containing abundant phagocytic cells debris. We did not find amastigote forms in tissues by histological and IHC techniques in positive qPCR bats. Our results allow us to hypothesize that phyllostomid bats seem to have an important role in reducing the risk of transmission, possibly acting as dead-end host.

Trypanosomatid diversity in a bat community of an urban area in Campo Grande, Mato Grosso do Sul, Brazil

Bats have a long evolutionary history with trypanosomatids, but the role of these flying mammals on parasite transmission cycles in urban areas, especially for Trypanosoma and Leishmania species, remains poorly known. The objective of this study was to evaluate the species richness of trypanosomatids parasitizing a bat community in Campo Grande (CG), a state capital within the Cerrado of the Brazilian Midwest. We evaluated 237 bats of 13 species by means of hemoculture and molecular detection in spleen samples. The bat community of CG appears to participate in the transmission cycles of various species of trypanosomatids. We report an overall trypanosomatid detection rate of 34.2% (n = 81), involving 11 out of 13 sampled bat species. We identified six species of trypanosomatids from 61 bats by analyzing SSU rRNA and/or kDNA: Trypanosoma cruzi DTU TcI, T. c. marinkellei, T. dionisii, Leishmania infantum, L. amazonensis, and T. janseni, with this latter being detected by hemoculture for the first time in a bat species. We also detected a Molecular Operational Taxonomic Unit, Trypanosoma sp. DID, in the phyllostomids Glossophaga soricina and Platyrrhinus lineatus. The highest trypanosomatid richness was observed for Sturnira lilium, which hosted three species: L. infantum, T. dionisii and T. janseni. Given that visceral leishmaniasis is endemic in CG, special focus should be placed on L. infantum. Moreover, L. amazonensis and T. cruzi warrant attention, since these are zoonotic parasites responsible for human cases of tegumentary leishmaniasis and Chagas disease, respectively. In this respect, we discuss how bat communities may influence the Leishmania spp. transmission in endemic areas.

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Influence of landscape ecology and physiological implications in bats from different trophic guilds

Bats may serve as bioindicators of human impact on landscape ecology. This study aimed to evaluate the health condition of bats from different food guilds captured in two areas with different land use profiles in Brazil and to compare data on the oxidant-antioxidant balance and histopathological changes due to different anthropogenic pressures. Bats were collected from a protected area in Serra do Cipó National Park (SCNP), MG, Brazil, and an area with intense agricultural activity in the municipality of Uberaba (UB), MG, Brazil. Despite the differences in land use and occupation between the studied areas, bats showed similar responses. However, the trophic guilds were affected differently. Frugivorous bats in both areas showed lower activities of the enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) and concentrations of malondialdehyde (MDA) than other guilds, which can be explained by the greater intake of antioxidants from the diet in addition to the lower production of reactive oxygen species (ROS). Histopathological analysis of the livers revealed that the animals had a similar prevalence in the two areas, with some differences related to guilds. Compared with other bats, hematophagous bats from SCNP had a higher prevalence of steatosis and, together with frugivorous bats from Uberaba, had higher frequencies of ballooning degeneration, suggesting that these animals are subjected to anthropogenic factors capable of inducing disturbances in hepatic metabolism. Hematophagous bats from Uberaba had a higher prevalence of portal inflammation, while insectivorous bats from Uberaba had a higher prevalence of lobular and portal inflammation. The profiles of use and occupation of the areas are different; Uberaba bats seem to face worse conditions because they show more liver damage owing to lipoperoxidation.

Chiropterans as a potential hosts of Leishmania spp. in endemic areas for leishmaniasis in northeastern Brazil

The species of the genus Leishmania are protozoa that are widely distributed from Asia to the Americas, affecting humans and wild and domestic animals. Little is known about infection by Leishmania in bats in the state of Maranhão, Brazil. The objective of this study was to investigate the presence of Leishmania in bats in Maranhão. Blood samples were collected from bat species for parasitological diagnosis. Samples of spleen and liver were collected for molecular analysis. All the blood cultures were negative. In two blood smears, organisms similar to amastigotes of Leishmania sp. were detected. Of the 116 samples, two spleen samples were positive and showed similarity to Leishmania infantum. Therefore, further studies are needed to elucidate whether bats take part in the epidemiological chain of leishmaniasis.

Bats as hosts of Leishmania (Leishmania) infantum in Minas Gerais, an endemic area for visceral leishmaniasis

Bats are parasitized by a wide spectrum of ecto and endoparasites, but their role as a reservoir for some zoonoses is not fully understood. The objective of this work was to evaluate the presence of Leishmania DNA in the blood of bats from 30 municipalities in the state of Minas Gerais, Brazil. We analyzed samples of 120 bats, covering 29 species. The blood samples were used for DNA extraction and submitted to conventional PCR analysis with primers directed to the Leishmania ITS-1 region of the rRNA. In total, 1.67% (2/120 samples) were positive for Leishmania spp., detected in animals from the metropolitan region of Belo Horizonte, the state capital. Sequencing of the positive samples revealed that both bats were infected with Leishmania (Leishmania) infantum. Considering the adaptability of some bats species to synanthropic environments, the results of the present work can contribute to a better comprehension of the leishmaniasis cycle and epidemiology.

Leishmania diversity in bats from an endemic area for visceral and cutaneous leishmaniasis in Southeastern Brazil

This study aimed to determine the occurrence of Leishmania infection in bats in urban and wild areas in an endemic municipality for visceral and cutaneous leishmaniasis in Minas Gerais, Brazil. Between April 2014 to April 2015, 247 bats were captured and classified into 26 species belonging to Phyllostomidae (90.7%), Vespertilionidae (8.1%) and Molossidae (1.2%) families. Blood samples from 247 bats were collected and submitted to nested-PCR, targeting the variable V7-V8 region of the SSU rRNA gene, followed by sequencing of the PCR product. The overall infection rate of Leishmania spp. in bats was 4.4%. Of the eleven bats infected, ten were frugivorous bats: Artibeus planirostris (8/11), Artibeus lituratus (1/11) and Artibeus cinereus (1/11) and one a nectarivorous bat (Glossophaga soricina). None of the individuals exhibited macroscopic alterations in the skin, spleen or liver. Phylogenetic analysis separated Leishmania species in clades corresponding to the subgenera Viannia, Leishmania, and Mundinia, and supported that the isolates characterized in the present study clustered closely with Leishmania (Viannia) sp., Leishmania (Leishmania) infantum and Leishmania (Leishmania) amazonensis. Here we report for the first time the bat Artibeus cinereus as a host of Leishmania (Leishmania) amazonensis. In the study we found that the mean abundance of bats did not differ in wild habitats and urban areas and that bat-parasite interactions were similarly distributed in the two environments. On the other hand, further studies should be conducted in more recent times to verify whether there have been changes in these parameters.

High-resolution melting analysis identifies reservoir hosts of zoonotic Leishmania parasites in Tunisia

BACKGROUND

Leishmaniasis is endemic in Tunisia and presents with different clinical forms, caused by the species Leishmania infantum, Leishmania major, and Leishmania tropica. The life cycle of Leishmania is complex and involves several phlebotomine sand fly vectors and mammalian reservoir hosts. The aim of this work is the development and evaluation of a high-resolution melting PCR (PCR-HRM) tool to detect and identify Leishmania parasites in wild and domestic hosts, constituting confirmed (dogs and Meriones rodents) or potential (hedgehogs) reservoirs in Tunisia.

METHODS

Using in vitro-cultured Leishmania isolates, PCR-HRM reactions were developed targeting the 7SL RNA and HSP70 genes. Animals were captured or sampled in El Kef Governorate, North West Tunisia. DNA was extracted from the liver, spleen, kidney, and heart from hedgehogs (Atelerix algirus) (n = 3) and rodents (Meriones shawi) (n = 7) and from whole blood of dogs (n = 12) that did not present any symptoms of canine leishmaniasis. In total, 52 DNA samples were processed by PCR-HRM using both pairs of primers.

RESULTS

The results showed melting curves enabling discrimination of the three Leishmania species present in Tunisia, and were further confirmed by Sanger sequencing. Application of PCR-HRM assays on reservoir host samples showed that overall among the examined samples, 45 were positive, while seven were negative, with no Leishmania infection. Meriones shawi were found infected with L. major, while dogs were infected with L. infantum. However, co-infections with L. major/L. infantum species were detected in four Meriones specimens and in all tested hedgehogs. In addition, multiple infections with the three Leishmania species were found in one hedgehog specimen. Sequence analyses of PCR-HRM products corroborated the Leishmania species found in analyzed samples.

CONCLUSIONS

The results of PCR-HRM assays applied to field specimens further support the possibility of hedgehogs as reservoir hosts of Leishmania. In addition, we showed their usefulness in the diagnosis of canine leishmaniasis, specifically in asymptomatic dogs, which will ensure a better evaluation of infection extent, thus improving elaboration of control programs. This PCR-HRM method is a robust and reliable tool for molecular detection and identification of Leishmania and can be easily implemented in epidemiological surveys in endemic regions.

Leishmania infantum infecting the carnivore Nasua nasua from urban forest fragments in an endemic area of visceral leishmaniasis in Brazilian Midwest

Introduction

The aim of the present study was to investigate the occurrence of Leishmania infantum in South American coatis inhabiting two forest fragments in Campo Grande, Mato Grosso do Sul, Midwest region of Brazil, an endemic area of human and canine visceral leishmaniasis (VL).

Material and methods

A total of 110 South American coatis were sampled in the conservation unit "Parque Estadual do Prosa" (PEP) and in the residential area "Vila da Base Aérea" (VBA) from March 2018 to April 2019. As a longitudinal study that include up to six recaptures of the same individual, a total of 190 capture events were obtained. Blood, bone marrow and skin samples were obtained for parasitological (axenic culture), serological (Enzyme Linked Immunosorbent Assay - ELISA and Dual-path Platform immunoassay - DPP^® CVL) and molecular diagnostic assays (targeting kDNA for Leishmania spp. and L. infantum; and HSP70 followed by sequence analysis).

Results

Seropositivity for L. infantum was found in 33 individuals, six in PEP and 27 in VBA. Furthermore, L. infantum was detected by molecular analysis in 16 individuals, seven from PEP and nine from VBA. We also isolated L. infantum from bone marrow of one individual and detected a single positive skin sample in molecular assay from other individual, both from VBA.

Discussion

An overall infection rate of 36.4% (40/110) was observed, significantly higher in the VBA (49.1%) than in the PEP (21.6%), probably because VBA presents: (i) a large number of resident dogs and chickens that would be attracting sandflies; (ii) a denser population of this wild mammal species; and (iii) physical barriers and a lack of functional connectivity in the surroundings, preventing these animals to disperse out. We conclude that South American coati populations living in urban forest fragments of Campo Grande are affected by the epidemiological scenario of VL, known to involve dogs, vectors and humans. We highlight the importance of investigate the parasitism by L. infantum in this and other potential L. infantum reservoirs that inhabit urbanized regions endemic to VL.

A Systematic Review (1990-2021) of Wild Animals Infected with Zoonotic Leishmania

Leishmaniasis are neglected diseases caused by several species of Leishmania that affect humans and many domestic and wild animals with a worldwide distribution. The objectives of this review are to identify wild animals naturally infected with zoonotic Leishmania species as well as the organs infected, methods employed for detection and percentage of infection. A literature search starting from 1990 was performed following the PRISMA methodology and 161 reports were included. One hundred and eighty-nine species from ten orders (i.e., Carnivora, Chiroptera, Cingulata, Didelphimorphia, Diprotodontia, Lagomorpha, Eulipotyphla, Pilosa, Primates and Rodentia) were reported to be infected, and a few animals were classified only at the genus level. An exhaustive list of species; diagnostic techniques, including PCR targets; infected organs; number of animals explored and percentage of positives are presented. L. infantum infection was described in 98 wild species and L. (Viania) spp. in 52 wild animals, while L. mexicana, L. amazonensis, L. major and L. tropica were described in fewer than 32 animals each. During the last decade, intense research revealed new hosts within Chiroptera and Lagomorpha. Carnivores and rodents were the most relevant hosts for L. infantum and L. (Viannia) spp., with some species showing lesions, although in most of the studies clinical signs were not reported.

Bats, Pathogens, and Species Richness

Bats carry many viruses, but this is not sufficient to threaten humans. Viruses must mutate to generate the ability to transfer to humans. A key factor is the diversity of species. With 1400 species of bats (20% of all species of mammals), the diversity of bats species is highly favorable to the emergence of new viruses. Moreover, several species of bats live within the same location, and share advanced social behavior, favoring the transmission of viruses. Because they fly, bats are also hosts for a wide range of viruses from many environments. They also eat everything (including what humans eat), they share humans’ environment and become closer to domestic species, which can serve as relays between bats and humans. Bats also have a long-life expectancy (up to 40 years for some bats), which is particularly effective for transmission to humans. However, a recent publication came out challenging what we think about bats. Proportionally, bats may not carry a higher number of zoonotic pathogens, normalized by species richness, compared to other mammalian and avian species. Viral zoonotic risk is homogenous among taxonomic orders of mammalian and avian reservoir hosts, without evidence that bats carry more viruses that infect humans.

Intra- and Inter-Host Assessment of Bartonella Diversity with Focus on Non-Hematophagous Bats and Associated Ectoparasites from Brazil

The relationship among bats, ectoparasites and associated microorganisms is important to investigate how humans can become exposed to zoonotic agents. Even though the diversity of Bartonella spp. in bats and ectoparasites has been previously reported, the occurrence of gltA genotypes within hosts has not been assessed so far. We aimed to investigate the genetic diversity of Bartonella spp. in non-hematophagous bats and associated ectoparasites by assessing cloned gltA Bartonella genotypes in intra- and inter-hosts levels, as well as by using three additional molecular markers. Overall, 13.5% (18/133) bat blood samples, 17.18% bat flies (11/64) and 23.8% (5/21) Macronyssidae mite pools showed to be positive for Bartonella spp. Seventeen positive samples were submitted to gltA-cloning and three clones were sequenced for each sample. We also obtained 11, seven and three sequences for nuoG, rpoB and ftsZ genes, respectively. None were positive for the other target genes. We found at least two genotypes among the three gltA-cloned sequences from each sample, and 13 between all the 51 sequences. Among the nuoG, rpoB and ftsZ sequences we found eight, five and three genotypes, respectively. In the phylogenetic analysis, the sequences were positioned mainly in groups related to Bartonella identified in rodents, bats and bat flies. Herein, we showed the genetic diversity of Bartonella in bat's blood and associated ectoparasites samples at both intra- and inter-host levels.

First detection of Leishmania infantum in common urban bats Pipistrellus pipistrellus in Europe

Leishmania infantum is a protozoan causing leishmaniasis in humans and in dogs, among other animals, which is an endemic disease in the Mediterranean basin. In recent years, the role of wildlife as a possible reservoir of the disease was analyzed and several species of carnivores were reported to have the highest infection rates, with foxes and wolves being the more widely studied species; the role of rabbits and hares as reservoirs of leishmaniasis has also been described. In addition, several studies highlighted the role of bats as suitable hosts for Leishmania species (L. braziliensis, L. major, L. mexicana, and L. tropica) in South and Central America and Africa, but no Leishmania spp. infection in Chiroptera has been reported in Europe. In this study, samples from spleen, hair, and blood were analyzed to detect L. infantum DNA in bats from the Community of Madrid (Spain). Infection by L. infantum was detected in 59.2% of the bats studied (n = 16/27), with the spleen being selected as the site for detection, yielding 14/16 positive results (87.5% sensitivity), followed by hair (n = 7/16) and blood (n = 6/16). In two animals, samples from all three anatomical sites tested positive (7.4% of the total animals), while in four animals the spleen and hair samples tested positive (14.8%), in one animal the blood and hair samples tested positive (3.7%), and in another animal the blood sample only tested positive (3.7%). This is the first report of L. infantum detection in the common urban bat (Pipistrellus pipistrellus) in Europe.