Inferring the disruption of rabies circulation in vampire bat populations using a betaherpesvirus-vectored transmissible vaccine.

Transmissible vaccines are an emerging biotechnology that hold prospects to eliminate pathogens from wildlife populations. Such vaccines would genetically modify naturally occurring, nonpathogenic viruses ("viral vectors") to express pathogen antigens while retaining their capacity to transmit. The epidemiology of candidate viral vectors within the target wildlife population has been notoriously challenging to resolve but underpins the selection of effective vectors prior to major investments in vaccine development. Here, we used spatiotemporally replicated deep sequencing to parameterize competing epidemiological mechanistic models of Desmodus rotundus betaherpesvirus (DrBHV), a proposed vector for a transmissible vaccine targeting vampire bat-transmitted rabies. Using 36 strain- and location-specific time series of prevalence collected over 6 y, we found that lifelong infections with cycles of latency and reactivation, combined with a high R0 (6.9; CI: 4.39 to 7.85), are necessary to explain patterns of DrBHV infection observed in wild bats. These epidemiological properties suggest that DrBHV may be suited to vector a lifelong, self-boosting, and transmissible vaccine. Simulations showed that inoculating a single bat with a DrBHV-vectored rabies vaccine could immunize >80% of a bat population, reducing the size, frequency, and duration of rabies outbreaks by 50 to 95%. Gradual loss of infectious vaccine from vaccinated individuals is expected but can be countered by inoculating larger but practically achievable proportions of bat populations. Parameterizing epidemiological models using accessible genomic data brings transmissible vaccines one step closer to implementation.

Virome analysis of Desmodus rotundus tissue samples from the Amazon region.

BACKGROUND: Bats are renowned for harboring a high viral diversity, their characteristics contribute to emerging infectious diseases. However, environmental and anthropic factors also play a significant role in the emergence of zoonotic viruses. Metagenomic is an important tool for investigating the virome of bats and discovering new viruses. RESULTS: Twenty-four families of virus were detected in lung samples by sequencing and bioinfomatic analysis, the largest amount of reads was focused on the Retroviridae and contigs assembled to Desmodus rotundus endogenous retrovirus, which was feasible to acquire complete sequences. The reads were also abundant for phages. CONCLUSION: This lung virome of D. rotundus contributes valuable information regarding the viral diversity found in bats, which is useful for understanding the drivers of viral cycles and their ecology in this species. The identification and taxonomic categorization of viruses hosted by bats carry epidemiological significance due to the potential for viral adaptation to other animals and humans, which can have severe repercussions for public health. Furthermore, the characterization of endogenized viruses helps to understanding the host genome and the evolution of the species.

Deforestation and Bovine Rabies Outbreaks in Costa Rica, 1985-2020.

In Latin America, rabies virus has persisted in a cycle between Desmodus rotundus vampire bats and cattle, potentially enhanced by deforestation. We modeled bovine rabies virus outbreaks in Costa Rica relative to land-use indicators and found spatial-temporal relationships among rabies virus outbreaks with deforestation as a predictor.

Dispersion and diversification of Lyssavirus rabies transmitted from haematophagous bats Desmodus rotundus: a phylogeographical study.

Rabies is worldwide zoonosis caused by Lyssavirus rabies (RABV) a RNA negative sense virus with low level of fidelity during replication cycle. Nucleoprotein of RABV is the most conserved between all five proteins of the virus and is the most used gene for phylogenetic and phylogeographic studies. Despite of rabies been very important in Public Health concern, it demands continuous prophylactic care for herbivores with economic interest, such as cattle and horses. The main transmitter of RABV for these animals in Brazil is the hematophagous bats Desmodus rotundus. The aim of this study was to determine the dispersion over time and space of RABV transmitted by D. rotundus. Samples of RABV from the State of São Paulo (SP), Southeast Brazil isolated from the central nervous system (CNS) of cattle, were submitted to RNA extraction, RT-PCR, sequencing and phylogeographic analyzes with BEAST (Bayesian Evolutionary Analysis Sampling Trees) v 2.5 software. Was possible to identify high rate of diversification in starts sublineages of RABV what are correlated with a behavior of D. rotundus, the main transmitter of rabies to cattle. This study also highlights the importance of continuous monitoring of genetic lineages of RABV in Brazil.

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.

Ecological determinants of rabies virus dynamics in vampire bats and spillover to livestock.

The pathogen transmission dynamics in bat reservoirs underpin efforts to reduce risks to human health and enhance bat conservation, but are notoriously challenging to resolve. For vampire bat rabies, the geographical scale of enzootic cycles, whether environmental factors modulate baseline risk, and how within-host processes affect population-level dynamics remain unresolved. We studied patterns of rabies exposure using an 11-year, spatially replicated sero-survey of 3709 Peruvian vampire bats and co-occurring outbreaks in livestock. Seroprevalence was correlated among nearby sites but fluctuated asynchronously at larger distances. A generalized additive mixed model confirmed spatially compartmentalized transmission cycles, but no effects of bat demography or environmental context on seroprevalence. Among 427 recaptured bats, we observed long-term survival following rabies exposure and antibody waning, supporting hypotheses that immunological mechanisms influence viral maintenance. Finally, seroprevalence in bats was only weakly correlated with outbreaks in livestock, reinforcing the challenge of spillover prediction even with extensive data. Together our results suggest that rabies maintenance requires transmission among multiple, nearby bat colonies which may be facilitated by waning of protective immunity. However, the likelihood of incursions and dynamics of transmission within bat colonies appear largely independent of bat ecology. The implications of these results for spillover anticipation and controlling transmission at the source are discussed.

Demographic and environmental drivers of metagenomic viral diversity in vampire bats.

Viruses infect all forms of life and play critical roles as agents of disease, drivers of biochemical cycles and sources of genetic diversity for their hosts. Our understanding of viral diversity derives primarily from comparisons among host species, precluding insight into how intraspecific variation in host ecology affects viral communities or how predictable viral communities are across populations. Here we test spatial, demographic and environmental hypotheses explaining viral richness and community composition across populations of common vampire bats, which occur in diverse habitats of North, Central and South America. We demonstrate marked variation in viral communities that was not consistently predicted by a null model of declining community similarity with increasing spatial or genetic distances separating populations. We also find no evidence that larger bat colonies host greater viral diversity. Instead, viral diversity follows an elevational gradient, is enriched by juvenile-biased age structure, and declines with local anthropogenic food resources as measured by livestock density. Our results establish the value of linking the modern influx of metagenomic sequence data with comparative ecology, reveal that snapshot views of viral diversity are unlikely to be representative at the species level, and affirm existing ecological theories that link host ecology not only to single pathogen dynamics but also to viral communities.

The expression patterns of aquaporin 9, vacuolar H+-ATPase, and cytokeratin 5 in the epididymis of the common vampire bat.

Desmodus rotundus is a vampire bat species that inhabits Latin America. Some basic aspects of this species' biology are still unknown, as the histophysiological characteristics of the male reproductive tract. Our study has focused on its epididymis, which is an important organ for performing a variety of functions, especially the sperm maturation and storage. The aim of this study was to identify principal, narrow, clear, and basal cells using cell-specific markers such as aquaporin 9 (AQP9), vacuolar H+-ATPase (V-ATPase), and cytokeratin 5 (KRT5). Principal cells were labeled by AQP9 from initial segment to cauda region in their stereocilia. They were shown with a columnar shape, whereas V-ATPase-rich cells were identified with a goblet-shaped body along the entire epididymis, including the initial segment, which were named as clear cells. Pencil-shaped V-ATPase-rich cells (narrow cells) were not detected in the initial segment of the bat epididymis, unlike in the rodent. Basal cells were labeled by KRT5 and were located at the basal portion of the epithelium forming a dense network. However, no basal cells with a luminal-reaching body extension were observed in the bat epididymis. In summary, epithelial cells were identified by their specific markers in the vampire bat epididymis. Principal and basal cells were labeled by AQP9 and KRT5, respectively. Narrow cells were not observed in the vampire bat epididymis, whereas clear cells were identified by V-ATPase labeling along the entire duct in a goblet-shaped body. In addition, no luminal-reaching basal cells were observed in the vampire bat epididymis.

Novel hemotropic mycoplasmas are widespread and genetically diverse in vampire bats.

Bats (Order: Chiroptera) have been widely studied as reservoir hosts for viruses of concern for human and animal health. However, whether bats are equally competent hosts of non-viral pathogens such as bacteria remains an important open question. Here, we surveyed blood and saliva samples of vampire bats from Peru and Belize for hemotropic Mycoplasma spp. (hemoplasmas), bacteria that can cause inapparent infection or anemia in hosts. 16S rRNA gene amplification of blood showed 67% (150/223) of common vampire bats (Desmodus rotundus) were infected by hemoplasmas. Sequencing of the 16S rRNA gene amplicons revealed three novel genotypes that were phylogenetically related but not identical to hemoplasmas described from other (non-vampire) bat species, rodents, humans, and non-human primates. Hemoplasma prevalence in vampire bats was highest in non-reproductive and young individuals, did not differ by country, and was relatively stable over time (i.e., endemic). Metagenomics from pooled D. rotundus saliva from Peru detected non-hemotropic Mycoplasma species and hemoplasma genotypes phylogenetically similar to those identified in blood, providing indirect evidence for potential direct transmission of hemoplasmas through biting or social contacts. This study demonstrates vampire bats host several novel hemoplasmas and sheds light on risk factors for infection and basic transmission routes. Given the high frequency of direct contacts that arise when vampire bats feed on humans, domestic animals, and wildlife, the potential of these bacteria to be transmitted between species should be investigated in future work.

Ectoparasitic hematophagous dipters: potential reservoirs of dengue virus? / Dípteros ectoparásitos hematófagos: ¿reservorios potenciales del virus del dengue?

Recently, the presence of antibodies and dengue virus (DV) RNA in neotropical wild mammals, including Desmodus rotundus, was reported. In a previous study, DV was also found in a high percentage (39.6%) of ectoparasitic hematophagous dipters specifics of these hematophagous bats. In order to verify the susceptibility of these ectoparasites to DV, in this work experimental infections with VD2 of organs explants of Strebla wiedemanni and of Melophagus ovinus were performed using C6/36 cells as control. Viral titers (UFP/mL) were determined at 0, 48 and 96 hrs pi. Infected organs were observed by electron microscopy and under the confocal microscopy indirect immunofluorescence (IIF) using specific conjugates against DV. The infected organs of both species of ectoparasites replicated DV at titers similar to those obtained with the C6/36 cell line (≥106 UFP/mL). Electron microscopy and IIF showed DV replication in the digestive tract, tracheoles, reproductive organs of males but not in females, and milk glands (MG) of both species. In the fatty bodies of the MG of M. ovinus, zones with a high affinity for the DV were observed. In this work the susceptibility of S. wiedemanni and M. ovinus to DV was demonstrated and consequently the probable role of this ectoparasites as wild reservoirs of DV.

Spatial pattern of genetic diversity and selection in the MHC class II DRB of three Neotropical bat species.

BACKGROUND: Although bats are natural reservoirs of many pathogens, few studies have been conducted on the genetic variation and detection of selection in major histocompatibility complex (MHC) genes. These genes are critical for resistance and susceptibility to diseases, and host-pathogen interactions are major determinants of their extensive polymorphism. Here we examined spatial patterns of diversity of the expressed MHC class II DRB gene of three sympatric Neotropical bats, Carollia perspicillata and Desmodus rotundus (Phyllostomidae), and Molossus molossus (Molossidae), all of which use the same environments (e.g., forests, edge habitats, urban areas). Comparison with neutral marker (mtDNA D-loop) diversity was performed at the same time. RESULTS: Twenty-three DRB alleles were identified in 19 C. perspicillata, 30 alleles in 35 D. rotundus and 20 alleles in 28 M. molossus. The occurrence of multiple DRB loci was found for the two Phyllostomidae species. The DRB polymorphism was high in all sampling sites and different signatures of positive selection were detected depending on the environment. The patterns of DRB diversity were similar to those of neutral markers for C. perspicillata and M. molossus. In contrast, these patterns were different for D. rotundus for which a geographical structure was highlighted. A heterozygote advantage was also identified for this species. No recombination or gene conversion event was found and phylogenetic relationships showed a trans-species mode of evolution in the Phyllostomids. CONCLUSIONS: This study of MHC diversity demonstrated the strength of the environment and contrasting pathogen pressures in shaping DRB diversity. Differences between positively selected sites identified in bat species highlighted the potential role of gut microbiota in shaping immune responses. Furthermore, multiple geographic origins and/or population admixtures observed in C. perspicillata and M. molossus populations acted as an additional force in shaping DRB diversity. In contrast, DRB diversity of D. rotundus was shaped by environment rather than demographic history.

First finding of Trypanosoma cruzi II in vampire bats from a district free of domestic vector-borne transmission in Northeastern Argentina.

Establishing the putative links between sylvatic and domestic transmission cycles of Trypanosoma cruzi, the etiological agent of Chagas disease, is of public health relevance. We conducted three surveys to assess T. cruzi infection in wild mammals from a rural and a preserved area in Misiones Province, Northeastern Argentina, which had recently been declared free of vector- and blood-borne transmission of human T. cruzi infection. A total of 200 wild mammals were examined by xenodiagnosis (XD) and/or polymerase chain reaction (PCR) amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR). The overall prevalence of T. cruzi infection was 8%. Nine (16%) of 57 Didelphis albiventris opossums and two (7%) of 29 Desmodus rotundus vampire bats were positive by both XD and kDNA-PCR. Additionally, one D. rotundus positive for T. cruzi by kDNA-PCR tested positive by satellite-DNA-PCR (SAT-DNA-PCR). The T. cruzi-infected bats were captured indoors and in the yard of a vacant dwelling. All D. albiventris were infected with TcI and both XD-positive D. rotundus by TcII. Fifty-five opossum cubs within the marsupium were negative by XD. The mean infectiousness to the vector was 62% in D. albiventris and 50% in D. rotundus. Mice experimentally infected with a parasite isolate from a vampire bat displayed lesions typically caused by T. cruzi. Our study documents the presence of the genotype TcII in a sylvatic host for the first time in Argentina, and the occurrence of two transmission cycles of T. cruzi in a district free of domestic vector-borne transmission.

Resolving the roles of immunity, pathogenesis, and immigration for rabies persistence in vampire bats.

Bats are important reservoirs for emerging infectious diseases, yet the mechanisms that allow highly virulent pathogens to persist within bat populations remain obscure. In Latin America, vampire-bat-transmitted rabies virus represents a key example of how such uncertainty can impede efforts to prevent cross-species transmission. Despite decades of agricultural and human health losses, control efforts have had limited success. To establish persistence mechanisms of vampire-bat-transmitted rabies virus in Latin America, we use data from a spatially replicated, longitudinal field study of vampire bats in Peru to parameterize a series of mechanistic transmission models. We find that single-colony persistence cannot occur. Instead, dispersal of bats between colonies, combined with a high frequency of immunizing nonlethal infections, is necessary to maintain rabies virus at levels consistent with field observations. Simulations show that the strong spatial component to transmission dynamics could explain the failure of bat culls to eliminate rabies and suggests that geographic coordination of control efforts might reduce transmission to humans and domestic animals. These findings offer spatial dynamics as a mechanism for rabies persistence in bats that might be important for the understanding and control of other bat-borne pathogens.

MYOSITIS OSSIFICANS TRAUMATICA IN A VAMPIRE BAT (DESMODUS ROTUNDUS).

A 15-yr-old sexually intact female vampire bat ( Desmodus rotundus ) was diagnosed with myositis ossificans traumatica of the abdominal wall. The bat presented with a large ulcerated firm mass along the abdomen. Radiographs and cytology were performed, followed by surgical exploration. The mass was determined to be nonresectable and the bat was euthanized. Histopathology showed severe necrotizing, degenerative, and pyogranulomatous myositis with osseous and cartilaginous metaplasia, fibrosis, and ulceration, which were consistent with myositis ossificans traumatica. Myositis ossificans traumatica is commonly associated with previous trauma to skeletal muscle. Two years prior, this bat had an emergency Caesarian section at this site, which was postulated to elicit a marked tissue response leading to this condition. Myositis ossificans traumatica is infrequently reported in humans, dogs, cats, pigs, and horses. To the author's knowledge, this is the first report of this condition in a bat.

Social benefits of non-kin food sharing by female vampire bats.

Regurgitations of blood among vampire bats appear to benefit both direct and indirect fitness. To maximize inclusive fitness, reciprocal food sharing should occur among close kin. Why then do females with kin roost-mates help non-kin? We tested the hypothesis that helping non-kin increases a bat's success at obtaining future donations by expanding its network of potential donors. On six occasions, we individually fasted 14 adult females and measured donations from 28 possible donors. Each female was fasted before, during and after a treatment period, when we prevented donations from past donors (including 10 close relatives) by simultaneously fasting or removing them. This experiment was designed to detect partner switching and yielded three main results. First, females received less food when we prevented donations from a past donor versus a control bat. Donors within a group are therefore not interchangeable. Second, the treatment increased the variance in donors' contributions to food received by subjects, suggesting the possibility of alternative responses to a partner's inability to reciprocate. Finally, bats that fed more non-kin in previous years had more donors and received more food during the treatment. These results indicate that a bat can expand its network of possible donors by helping non-kin.

Intranasal oxytocin increases social grooming and food sharing in the common vampire bat Desmodus rotundus.

Intranasal oxytocin (OT) delivery has been used to non-invasively manipulate mammalian cooperative behavior. Such manipulations can potentially provide insight into both shared and species-specific mechanisms underlying cooperation. Vampire bats are remarkable for their high rates of allogrooming and the presence of regurgitated food sharing among adults. We administered intranasal OT to highly familiar captive vampire bats of varying relatedness to test for an effect on allogrooming and food sharing. We found that intranasal OT did not have a detectable effect on food-sharing occurrence, but it did increase the size of regurgitated food donations when controlling for dyad and amount of allogrooming. Intranasal OT in females increased the amount of allogrooming per partner and across all partners per trial, but not the number of partners. We also found that the peak effect of OT treatments occurred 30-50min after administration, which is consistent with the reported latency for intranasal OT to affect relevant brain areas in rats and mice. Our results suggest that intranasal OT is a potential tool for influencing dyadic cooperative investments, but measuring prior social relationships may be necessary to interpret the results of hormonal manipulations of cooperative behavior and it may be difficult to alter partner choice in vampire bats using intranasal OT alone.

Pre-Exposure Prophylaxis to Prevent Hematophagous Bat-Mediated Rabies Outbreaks in Remote Amazon Communities: Lessons from a Pilot for Public Health Policy.

In 2018, an outbreak of human rabies caused by the hematophagous bat Desmodus rotundus hit the Brazilian Amazon Basin community of Melgaço, Brazil, resulting in the death of 10 people, 9 of them children. The incidence of rabies has been on the rise among populations in conditions of vulnerability in this ecosystem due to human expansion into sylvatic environments and limited access to public health services. To address this issue, in September 2019, a collaborative effort from national, local, and international institutions promoted and executed a pilot for pre-exposure prophylaxis of a population in high-risk areas for hematophagous bat-mediated rabies. This measure is usually only implemented in response to outbreaks. The pilot was conducted in Portel, in a nearby location to the previous outbreak, with the use of fluvial transportation, and 2987 individuals in 411 dwellings were successfully vaccinated. It established a methodology for pre-exposure prophylaxis for populations in conditions of vulnerability, identifying logistics and costs, as well as characterizing the target riverine population regarding risk factors associated with bites by hematophagous bats. This approach offers a proactive measure to prevent future outbreaks and provides valuable insights into how to address the issue of rabies in remote and difficult-to-reach areas.

Epidemiology and Control of Rabies in Cattle and Equines in Rondônia State, a Brazilian's Legal Amazon Area.

Rabies is a fatal neglected tropical zoonosis, and its significance for domestic herbivores in the rural cycle is probably associated with rainforest deforestation, livestock, and agricultural expansion. This epidemiological survey aimed to study the occurrence of rabies in bovines and equines in the state of Rondônia, located in the Brazilian's Legal Amazon, between the years 2002 and 2021, correlating these findings with the prophylactic strategies adopted by the local sanitary agency for rabies control. During this period, 201 cases were observed in bovines and 23 in equines. A downward trend in rabies incidence was observed for both domestic herbivores. Rabies did not show a higher occurrence in any specific time of the year, and epidemic periods varied during some years for bovines and equines. Using the Generalized estimating equations (GEE) method, a multiple model approach was obtained with the explanatory variables significantly associated with the decrease in rabies incidence in cattle and horses during the study period: the ratio of treated bats and ratio of vaccine doses sold. Furthermore, the ratio of printed educative material was positively associated with rabies incidence. Despite a decreasing trend in rabies occurrences in this Amazon rainforest area, likely due to the actions taken by the animal sanitary agency, rabies remains endemic and requires monitoring, as well as prophylactic strategies to control this disease.

Novel Borrelia Genotypes from Brazil Indicate a New Group of Borrelia spp. Associated with South American Bats.

The bacterial genus Borrelia comprises vector-borne spirochetes that have been classified into three major groups: the relapsing fever group (RFG), the Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner sensu lato group (Bbsl), and the reptile-monotreme group (RMG). All three groups have been associated mainly with ticks and wild animals, especially rodents, birds, and reptiles. Here, we searched for Borrelia infection among 99 vampire bats [Desmodus rotundus (É. Geoffroy)] (Chiroptera: Phyllostomidae) from the Brazilian semiarid region. Through molecular investigation of bat internal organs, haplotypes of a potentially novel Borrelia organism were detected in 5% (5/99) of the bats. Borrelia DNA was detected in the liver, blood, spleen, kidney and brain, suggesting a systemic infection. Phylogenetic analyses inferred from partial sequences of the borrelial rrs and flaB genes indicated that the vampire bat-associated Borrelia sp. of this study form a monophyletic group with a newly reported Borrelia associated with a Colombia bat, distinct from the three main currently recognized groups of Borrelia spp., Bbsl, RFG, and RMG. These novel bat-associated Borrelia spp. from South America might have arisen through an independent event along the borrelial evolutionary history, since previous molecular reports of Borrelia organisms in bats or bat-associated ticks from Africa, Europe, and North America were all classified in the RFG.

Revealing the complexity of vampire bat rabies "spillover transmission".

BACKGROUND: The term virus 'spillover' embodies a highly complex phenomenon and is often used to refer to viral transmission from a primary reservoir host to a new, naïve yet susceptible and permissive host species. Spillover transmission can result in a virus becoming pathogenic, causing disease and death to the new host if successful infection and transmission takes place. MAIN TEXT: The scientific literature across diverse disciplines has used the terms virus spillover, spillover transmission, cross-species transmission, and host shift almost indistinctly to imply the complex process of establishment of a virus from an original host (source/donor) to a naïve host (recipient), which have close or distant taxonomic or evolutionary ties. Spillover transmission may result in unsuccessful onward transmission, if the virus dies off before propagation. Alternatively, successful viral establishment in the new host can occur if subsequent secondary transmission among individuals of the same novel species and among other sympatric susceptible species occurred. As such, virus spillover transmission is a common yet highly complex phenomenon that encompasses multiple subtle stages that can be deconstructed to be studied separately to better understand the drivers of disease emergence. Rabies virus (RABV) is a well-documented viral pathogen which still inflicts heavy impact on humans, companion animals, wildlife, and livestock throughout Latin America due substantial spatial temporal and ecological-natural and expansional-overlap with several virus reservoir hosts. Thereby, the rabies disease system represents a robust avenue through which the drivers and uncertainties surrounding spillover transmission can be unravel at its different subtle stages to better understand how they may be affected by coarse, medium, and fine scale variables. CONCLUSIONS: The continued study of viral spillover transmission necessitates the elucidation of its complexities to better assess the cross-scale impacts of ecological forces linked to the propensity of spillover success. Improving capacities to reconstruct and predict spillover transmission would prevent public health impacts on those most at risk populations across the globe.