The role of host traits and geography in shaping the gut microbiome of insectivorous bats.

The gut microbiome is a symbiotic microbial community associated with the host and plays multiple important roles in host physiology, nutrition, and health. A number of factors have been shown to influence the gut microbiome, among which diet is considered to be one of the most important; however, the relationship between diet composition and gut microbiota in wild mammals is still not well recognized. Herein, we characterized the gut microbiota of bats and examined the effects of diet, host taxa, body size, gender, elevation, and latitude on the gut microbiota. The cytochrome C oxidase subunit I (COI) gene and 16S rRNA gene amplicons were sequenced from the feces of eight insectivorous bat species in southern China, including Miniopterus fuliginosus, Aselliscus stoliczkanus, Myotis laniger, Rhinolophus episcopus, Rhinolophus osgoodi, Rhinolophus ferrumequinum, Rhinolophus affinis, and Rhinolophus pusillus. The results showed that the composition of gut microbiome and diet exhibited significant differences among bat species. Diet composition and gut microbiota were significantly correlated at the order, family, genus, and operational taxonomic unit levels, while certain insects had a marked effect on the gut microbiome at specific taxonomic levels. In addition, elevation, latitude, body weight of bats, and host species had significant effects on the gut microbiome, but phylosymbiosis between host phylogeny and gut microbiome was lacking. These findings clarify the relationship between gut microbiome and diet and contribute to improving our understanding of host ecology and the evolution of the gut microbiome in wild mammals. IMPORTANCE: The gut microbiome is critical for the adaptation of wildlife to the dynamic environment. Bats are the second-largest group of mammals with short intestinal tract, yet their gut microbiome is still poorly studied. Herein, we explored the relationships between gut microbiome and food composition, host taxa, body size, gender, elevation, and latitude. We found a significant association between diet composition and gut microbiome in insectivorous bats, with certain insect species having major impacts on gut microbiome. Factors like species taxa, body weight, elevation, and latitude also affected the gut microbiome, but we failed to detect phylosymbiosis between the host phylogeny and the gut microbiome. Overall, our study presents novel insights into how multiple factors shape the bat's gut microbiome together and provides a study case on host-microbe interactions in wildlife.

Detection of novel paramyxoviruses in Chaerephon bat species in Nigeria and phylogenetics of paramyxoviruses co-evolution with bats in Africa.

Bat paramyxoviruses (PmV) are a diverse group of viruses and include zoonotic viruses such as henipaviruses. Members of this group in other continents have been associated with severe respiratory and neurological infections in animals and humans. Furthermore, despite the richness of diverse bat species that can transmit this virus in African countries like Nigeria, there is very scanty information as to the presence and co-evolution of paramyxoviruses in bats. There is a need for continuous surveillance of zoonotic viruses and their biological reservoirs as this will help in the prevention and management of pathogens' spillovers. This study detected novel paramyxoviruses in Chaerephon nigeriae bat species found in Badagry, Lagos. Phylogenetic analyses of paramyxovirus sequences' co-evolution with frugivorous and insectivorous bats circulating in African countries were also performed using sequences of African origin available in the Database of Bat-Associated Viruses (DBatVir: http://www.mgc.ac.cn/DBatVir/). Oral swabs (n = 18) and blood samples (n = 32) were collected from C. nigeriae bats in Badagry, Lagos. The L gene of bat paramyxovirus was detected in all oral swabs using PCR techniques. Six of the amplicons were successfully sequenced. Estimated phylogenies placed the sequences in close relationship with those isolated from insectivorous bats. Phylogenetic analyses of previously sequenced isolates in the African region showed the likelihood of different co-evolution mechanisms of paramyxoviruses with frugivorous bats compared with insectivorous bats. This may be due to codon usage bias of the L gene. Spatial distribution of paramyxoviruses in African countries showed limited ongoing surveillance of this virus in the continent, especially in southern and northern countries. Extensive surveillance of paramyxoviruses with possible zoonotic potentials among bat species in the continent is recommended. This will provide further insights into co-evolution as well as prevent possible spillover into the human population.

Three-dimensional stratification pattern in an old-growth lowland forest: How does height in canopy and season influence temperate bat activity?

The study of animal-habitat interactions is of primary importance for the formulation of conservation recommendations. Flying, gliding, and climbing animals have the ability to exploit their habitat in a three-dimensional way, and the vertical canopy structure in forests plays an essential role for habitat suitability. Forest bats as flying mammals may seasonally shift their microhabitat use due to differing energy demands or changing prey availability, but the patterns are not well understood. We investigated three-dimensional and seasonal habitat use by insectivorous bats in a temperate lowland old-growth forest, the Belovezhskaya Pushcha in Belarus. We acoustically sampled broadleaved and mixed coniferous plots in the forest interior and in gaps in three heights during two reproductive periods (pregnancy/lactation vs. postlactation). In canopy gaps, vertical stratification in bat activity was less pronounced than in the forest interior. Vertical activity patterns differed among species. The upper canopy levels were important foraging habitats for the open-space forager guild and for some edge-space foragers like the Barbastelle bat Barbastella barbastellus and the soprano pipistrelle Pipistrellus pygmaeus. Myotis species had highest activity levels near the ground in forest gaps. Moreover, we found species-dependent seasonal microhabitat shifts. Generally, all species and species groups considered except Myotis species showed higher activity levels during postlactation. Myotis species tended toward higher activity in the forest interior during postlactation. P. pygmaeus switched from high activity levels in the upper canopy during pregnancy and lactation to high activity levels near the ground during postlactation. We conclude that a full comprehension of forest bat habitat use is only possible when height in canopy and seasonal patterns are considered.

Quantitative evaluation of individual food intake by insectivorous vespertilionid bats (Chiroptera, Vespertilionidae).

Insectivorous bats provide important ecosystem services, especially by suppressing and controlling the insects' biomass. To empirically quantify the number of insects consumed by European vespertilionid bats per night, we estimated their ratio of dry mass of feces to mass of consumed insects. This study combines the results of feeding in captivity and the data obtained in field surveys; dry mass of feces was measured in both cases. In captivity, we analyzed the effect of species, age and sex of bats, species of insects consumed and the mass of food portion on the dry mass of feces. Using coefficients of the regression model, we estimated the number of insects consumed by free-ranging bats based on dry mass of their feces. According to our estimates, on average, one individual of one of the largest European bat species, Nyctalusnoctula, consumes 2.2 g (ranging from 0.5 to 8.2 g) of insects per one feeding night, while the smallest European bats of genus Pipistrellus consume 0.4 g (ranging from 0.1 to 1.3 g), further confirming the importance of insectivorous bats for ecosystem services. This publication offers the novel method for the estimation of insects' biomass consumed by bats.

Rickettsia spp. in bats of Romania: high prevalence of Rickettsia monacensis in two insectivorous bat species.

BACKGROUND: Spotted fever group rickettsiae represent one of the most diverse groups of vector-borne bacteria, with several human pathogenic species showing an emerging trend worldwide. Most species are vectored by ticks (Ixodidae), with many zoonotic reservoir species among most terrestrial vertebrate groups. While the reservoir competence of many different vertebrate species is well known (e.g. birds, rodents and dogs), studies on insectivorous bats have been rarely performed despite their high species diversity, ubiquitous urban presence and importance in harboring zoonotic disease agents. Romania has a high diversity and ubiquity of bats. Moreover, seven out of eight SFG rickettsiae species with zoonotic potential were previously reported in Romania. Based on this, the aim of this study was to detect Rickettsia species in tissue samples in bats. METHODS: Here we report a large-scale study (322 bats belonging to 20 species) on the presence of Rickettsia spp. in Romanian bat species. Tissue samples from insectivorous bats were tested for the presence of Rickettsia DNA using PCR detection amplifying a 381 bp fragment of the gltA gene. Positive results were sequenced to confirm the results. The obtained results were statistically analyzed by chi-squared independence test. RESULTS: Positive results were obtained in 14.6% of bat samples. Sequence analysis confirmed the presence of R. monacensis in two bat species (Nyctalus noctula and Pipistrellus pipistrellus) in two locations. CONCLUSION: This study provides the first evidence of a possible involvement of these bat species in the epidemiology of Rickettsia spp., highlighting the importance of bats in natural cycles of these vector-borne pathogens.

Micronucleus Test Reveals Genotoxic Effects in Bats Associated with Agricultural Activity.

Bats play a vital role in our ecosystems and economies as natural pest-control agents, seed dispersers, and pollinators. Agricultural intensification, however, can impact bats foraging near crops, affecting the ecosystem services they provide. Exposure to pesticides, for example, may induce chromosome breakage or missegregation that can result in micronucleus formation. Detection of micronuclei is a simple, inexpensive, and relatively minimally invasive technique commonly used to evaluate chemical genotoxicity but rarely applied to assess wildlife genotoxic effects. We evaluated the suitability of the micronucleus test as a biomarker of genotoxicity for biomonitoring field studies in bats. We collected blood samples from insectivorous bats roosting in caves surrounded by different levels of disturbance (agriculture, human settlements) in Colima and Jalisco, west central Mexico. Then, we examined the frequency of micronucleus inclusions in erythrocytes using differentially stained blood smears. Bats from caves surrounded by proportionately more (53%) land used for agriculture and irrigated year-round had higher micronucleus frequency than bats from a less disturbed site (15% agriculture). We conclude that the micronucleus test is a sensitive method to evaluate genotoxic effects in free-ranging bats and could provide a useful biomarker for evaluating risk of exposure in wild populations. Environ Toxicol Chem 2021;40:202-207. © 2020 SETAC.

Lyssaviruses in Insectivorous Bats, South Africa, 2003-2018.

We detected 3 lyssaviruses in insectivorous bats sampled in South Africa during 2003-2018. We used phylogenetic analysis to identify Duvenhage lyssavirus and a potentially new lyssavirus, provisionally named Matlo bat lyssavirus, that is related to West Caucasian bat virus. These new detections highlight that much about lyssaviruses remains unknown.

Identification of a Novel Yersinia enterocolitica Strain from Bats in Association with a Bat Die-Off That Occurred in Georgia (Caucasus).

Yersinia entercolitica is a bacterial species within the genus Yersinia, mostly known as a human enteric pathogen, but also recognized as a zoonotic agent widespread in domestic pigs. Findings of this bacterium in wild animals are very limited. The current report presents results of the identification of cultures of Y. entercolitica from dead bats after a massive bat die-off in a cave in western Georgia. The growth of bacterial colonies morphologically suspected as Yersinia was observed from three intestine tissues of 11 bats belonging to the Miniopterus schreibersii species. These three isolates were identified as Y. enterocolitica based on the API29 assay. No growth of Brucella or Francisella bacteria was observed from tissues of dead bats. Full genomes (a size between 4.6-4.7 Mbp) of the Yersinia strains isolated from bats were analyzed. The phylogenetic sequence analyses of the genomes demonstrated that all strains were nearly identical and formed a distinct cluster with the closest similarity to the environmental isolate O:36/1A. The bat isolates represent low-pathogenicity Biotype 1A strains lacking the genes for the Ail, Yst-a, Ysa, and virulence plasmid pYV, while containing the genes for Inv, YstB, and MyfA. Further characterization of the novel strains cultured from bats can provide a clue for the determination of the pathogenic properties of those strains.

The Sonozotz project: Assembling an echolocation call library for bats in a megadiverse country.

Bat acoustic libraries are important tools that assemble echolocation calls to allow the comparison and discrimination to confirm species identifications. The Sonozotz project represents the first nation-wide library of bat echolocation calls for a megadiverse country. It was assembled following a standardized recording protocol that aimed to cover different recording habitats, recording techniques, and call variation inherent to individuals. The Sonozotz project included 69 species of echolocating bats, a high species richness that represents 50% of bat species found in the country. We include recommendations on how the database can be used and how the sampling methods can be potentially replicated in countries with similar environmental and geographic conditions. To our knowledge, this represents the most exhaustive effort to date to document and compile the diversity of bat echolocation calls for a megadiverse country. This database will be useful to address a range of ecological questions including the effects of anthropogenic activities on bat communities through the analysis of bat sound.

Effects of imidacloprid, a neonicotinoid insecticide, on the echolocation system of insectivorous bats.

Imidacloprid, a widely used neonicotinoid insecticide, has led to a decline in the honey bee population worldwide. An invertebrate insect prey with neonicotinoid toxicity can adversely affect insectivores, such as echolocating bats. The aim of the current study was to examined whether imidacloprid toxicity may interfere echolocation system such as vocal, auditory, orientation, and spatial memory systems in the insectivorous bat. By comparing the ultrasound spectrum, auditory brainstem-evoked potential, and flight trajectory, we found that imidacloprid toxicity may interfere functions in vocal, auditory, orientation, and spatial memory system of insectivorous bats (Hipposideros armiger terasensis). As suggested from immunohistochemistry and western blots evidences, we found that insectivorous bats after suffering imidacloprid toxicity may decrease vocal-related FOXP2 expressions in the superior colliculus, auditory-related prestin expressions in the cochlea, and the auditory-related otoferlin expressions in the cochlea and the inferior colliculus, and cause inflammation and mitochondrial dysfunction-related apoptosis in the hippocampal CA1 and medial entorhinal cortex. These results may provide a reasonable explanation about imidacloprid-induced interference of echolocation system in insectivorous bats.

Viral Diversity of Microbats within the South West Botanical Province of Western Australia.

Bats are known reservoirs of a wide variety of viruses that rarely result in overt clinical disease in the bat host. However, anthropogenic influences on the landscape and climate can change species assemblages and interactions, as well as undermine host-resilience. The cumulative result is a disturbance of bat-pathogen dynamics, which facilitate spillover events to sympatric species, and may threaten bat communities already facing synergistic stressors through ecological change. Therefore, characterisation of viral pathogens in bat communities provides important basal information to monitor and predict the emergence of diseases relevant to conservation and public health. This study used targeted molecular techniques, serological assays and next generation sequencing to characterise adenoviruses, coronaviruses and paramyxoviruses from 11 species of insectivorous bats within the South West Botanical Province of Western Australia. Phylogenetic analysis indicated complex ecological interactions including virus-host associations, cross-species infections, and multiple viral strains circulating concurrently within selected bat populations. Additionally, we describe the entire coding sequences for five alphacoronaviruses (representing four putative new species), and one novel adenovirus. Results indicate that viral burden (both prevalence and richness) is not homogeneous among species, with Chalinolobus gouldii identified as a key epidemiological element within the studied communities.

Difference in glucose tolerance between phytophagous and insectivorous bats.

Bats are mostly insectivorous or phytophagous. It is hypothesized that bats are evolved from small insectivorous mammals. Therefore, the digestive and metabolic systems of phytophagous and insectivorous bats must have evolved differently to adapt to their dietary habits. To investigate the difference in sugar tolerance in bats, we determined changes in blood glucose levels after intraperitoneal (i.p.) injection of glucose in three species of phytophagous and four species of insectivorous bats under resting conditions. Results showed that phytophagous bats eliminated blood glucose faster than insectivorous bats. All three species of fruit bats reduced blood glucose to fasting levels within 30-45 min, whereas all insectivorous bats failed to lower blood glucose to fasting levels even 120 min after i.p. glucose injection. Taken together, results of this study suggest that bats have undergone adaptations and become diversified in dietary habits.

Street rabies virus strains associated with insectivorous bats are less pathogenic than strains isolated from other reservoirs.

Rabies is a fatal and viral zoonosis that causes acute, progressive encephalitis and remains an important concern in public health. In the last few years, there has been a change in the epidemiological profile of rabies after implementing canine rabies control in the Americas, which has led to a significant increase in both human and pet cases of rabies associated with insectivorous bats. Thus, it is important to understand the pathogenesis caused by Rabies virus (RABV) isolates from insectivorous bats. Viral growth kinetics, cell-to-cell spread and virus uptake in vitro were analyzed for RABV isolates from Eptesicus furiralis and Myotis nigricans. For pathogenesis evaluation, mice were inoculated with RABV isolates from Eptesicus furiralis and Myotis nigricans, and clinical signs were observed for 40 days. We observed that the insectivorous bat strains showed a higher replication rate, faster cell-to-cell spread and delayed virus uptake in N2a cells. Furthermore, after the first sign of a clinical infection, mice infected with Myotis nigricans and Eptesicus furiralis isolates succumbed rapidly (6 ±â€¯9 days) compared with RABV strains associated with other reservoirs. Our results show that the insectivorous bat RABV strains are less pathogenic for mice than strains associated with other reservoirs. In addition, this study also indicates that the differences in the biological characteristics of the RABV strains are important to their pathogenicity. An enhanced understanding of rabies pathogenesis may be important for the development of novel therapies for humans and in the implementation of rabies control strategies.

Survey of Ebola Viruses in Frugivorous and Insectivorous Bats in Guinea, Cameroon, and the Democratic Republic of the Congo, 2015-2017.

To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015-2017 from countries in Africa that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2-37 (0.05%-0.92%) bats were seropositive for Zaire and 0-30 (0%-0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.

Detection and phylogenetic characterization of astroviruses in insectivorous bats from Central-Southern Italy.

In recent years, bats have been found to harbour many viruses, raising several questions about their role as reservoirs and potential disseminators of zoonotic viruses. We investigated the presence of six virus families in bats in three regions of Central-Southern Italy. Astroviruses were identified in seven of 13 bat species. Sequence analysis revealed marked genetic heterogeneity among the astroviruses identified, with nucleotide identity ranging between 60.26% and 87.62%. Astrovirus diversity was not associated with the bat species, the geographic areas or the bat colony, suggesting the circulation of several astrovirus strains in Italian ecosystems. Genetic diversification and interspecies transmission appear common in bat astroviruses and could provide, potentially, the bases for transmission to humans and other mammals. Yet overemphasizing this risk might have detrimental consequences for bat conservation and preservation of the important ecosystem services bats provide.

Street rabies virus strains associated with insectivorous bats are less pathogenic than strains isolated from other reservoirs

Rabies is a fatal and viral zoonosis that causes acute, progressive encephalitis and remains an important concern in public health. In the last few years, there has been a change in the epidemiological profile of rabies after implementing canine rabies control in the Americas, which has led to a significant increase in both human and pet cases of rabies associated with insectivorous bats. Thus, it is important to understand the pathogenesis caused by Rabies virus (RABV) isolates from insectivorous bats. Viral growth kinetics, cell-to-cell spread and virus uptake in vitro were analyzed for RABV isolates from Eptesicus furiralis and Myotis nigricans. For pathogenesis evaluation, mice were inoculated with RABV isolates from Eptesicus furiralis and Myotis nigricans, and clinical signs were observed for 40 days. We observed that the insectivorous bat strains showed a higher replication rate, faster cell-to-cell spread and delayed virus uptake in N2a cells. Furthermore, after the first sign of a clinical infection, mice infected with Myotis nigricans and Eptesicus furiralis isolates succumbed rapidly (6?±?9 days) compared with RABV strains associated with other reservoirs. Our results show that the insectivorous bat RABV strains are less pathogenic for mice than strains associated with other reservoirs. In addition, this study also indicates that the differences in the biological characteristics of the RABV strains are important to their pathogenicity. An enhanced understanding of rabies pathogenesis may be important for the development of novel therapies for humans and in the implementation of rabies control strategies.

Interspecies variation in the risks of metals to bats.

A modeling framework was used to assess the risk of four metals to UK bat species. Eight species of bats were predicted to be "at risk" from one or more of the metals in over 5% of their ranges. Species differed significantly in their predicted risk. Contamination by Pb was found to pose the greatest risk, followed by Cu, Cd and Zn. A sensitivity analysis identified the proportion of invertebrates ingested as most important in determining the risk. We then compared the model predictions with a large dataset of metals concentrations in the tissues (liver, kidney) of Pipistrellus sp. from across England and Wales. Bats found in areas predicted to be the most "at risk" contained higher metal concentrations in their tissues than those found in areas predicted "not at risk" by the model. Our spatially explicit modeling framework provides a useful tool for further environmental risk assessment studies for wildlife species.

Implications of in vitro bioaccessibility differences for the assessment of risks of metals to bats.

Food chain modeling is often used to assess the risks of chemical contaminants to wildlife. In modeling efforts, bioaccessibility from different dietary components is assumed to be similar. The present study explored potential differences in the in vitro bioaccessibility of metals from a range of insect orders, which are common components of the diet of insectivorous bats, and assessed the implications of this for environmental exposure assessment. Bioaccessibility of metals was assessed using an in vitro gastric model simulating gastric and intestinal conditions of insectivorous bats. In vitro-derived metal bioaccessibility was found to differ significantly across insect orders. Bioaccessibility was found to be greatest in Coleoptera, followed by Lepidoptera and Diptera. To establish the implications for risk assessment, a spatially explicit risk model was employed that included and excluded in vitro bioaccessibility data; to examine the daily oral exposure of metals to 14 bat species. The results show that when bioaccessibility data are included in the model, metal exposure predictions across species are changed and that the ranking of bat species, in terms of metal exposure, are altered. The authors recommend that in vitro bioaccessibility data begin to be employed when establishing the risks of contaminants to wildlife species.

Species diversity and activity of insectivorous bats in three habitats in La Virgen de Sarapiquí, Costa Rica / Diversidad y actividad de especies de murciélagos insectívoros en tres hábitats de La Vírgen, de Sarapiquí, Costa Rica

Pineapple farms make up 45 000ha of Costa Rican landscape and are the second most exported crop. This is economically beneficial for the Costa Ricans, but greatly affects the natural flora and fauna because it is such a low growing crop. This study examined the differences in insectivorous bat species diversity and activity in the habitat gradient between the forest in Tirimbina Biological Reserve in La Virgen de Sarapiquí, Heredia, Costa Rica and the nearby pineapple farm called Finca Corsicana. Over a four week period in March and April 2013, ultrasonic recorders were placed at different sites to pick up the bats’ calls. Then the recordings were analyzed to identify the species. There were four families present and 19 different species. There was a significant decrease in the number of bat passes (the number of times a bat passes the recorder) in the pineapple farm (x=22.6), in comparison to the border (x=39.9), and the forest (x=44.2) (p=0.0028). Agricultural environ- ments affected and lowered bat presence. Also, a greater mean number of bats recorded between 1900-1930hrs compared to 1730-1800hrs, coincided with the setting of the sun and beginning of bat activity. More research is need throughout the night and the year to establish clearer patterns of bat use and activity in different habitats.

Hay 45 000ha de piñeras en Costa Rica. La piña es la segunda fruta de mayor exportación en el país, por lo cual es muy importante para la economía. Este cultivo beneficia al país en términos económicos; no obstante, tiene efectos negativos en la flora y la fauna de áreas naturales al ser una planta herbácea de baja altura. Esta investigación examinó la diversidad y actividad de los murciélagos insectívoros en el gradiente entre un bosque (Reserva Biológica Tirimbina) y una piñera (Finca Corsi- cana) en la Virgen, Sarapiquí, Costa Rica. Durante cuatro semanas, puse grabadoras en tres sitios (bosque, borde de bosque y piñera) para grabar las llamadas de los murcié- lagos. Después analicé las llamadas para identificar las especies. Encontré cuatro familias y 19 especies. Hubo una reducción en el número de pases de murciélagos (número de veces que un murciélago vuela al lado de la grabadora) en la piñera (x=22.6), en comparación con el borde de bosque (x=39.9) y el bosque (x=44.2) (p=0.0028). El ambiente agrícola afectó y redujo la presencia de murciéla- gos. Familias diferentes parecen estar adaptadas a hábitats diferentes. Finalmente, un mayor número de murciélagos fueron registrados entre las 19:00 y 19:30 hrs, comparados con las 17:30-18:00 hrs, lo cual coincide con el atardecer y el inicio de la actividad nocturna de los murciélagos. Se necesita más investigación, tanto en horas nocturnas, como del resto del año, para entender mejor los patrones de actividad y el uso de diferentes hábitats.

Rabies in the insectivorous Pallas's mastiff bat (Molossus molossus) in northeastern Brazil.

We describe the pathologic and immunohistochemical findings in five cases of rabies in the insectivorous Pallas's mastiff bat (Molossus molossus) in the city of Patos, state of Paraíba, northeastern Brazil. All cases were found during the day, in different neighborhoods, prostrate and unable to fly. No significant lesions were observed at necropsy or on histologic examination. The brains of the five bats showed strong immunohistochemical labeling for rabies virus in the form of large corpuscles or multiple clusters of granules within the perikarya of neurons in different areas of the brain, mainly in the cerebral cortex and cerebellar Purkinje cells. Three bats tested by direct immunofluorescence and mouse inoculation were also positive for rabies. These data demonstrate that M. molossus may be infected with the rabies virus and develop rabies, even without histologic lesions in the central nervous system, and can be a source of infection for humans and domestic animals.