Parasite and viral species richness of Southeast Asian bats: Fragmentation of area distribution matters

Differential prevalence and risk factors for infection with coronaviruses in bats collected from Yunnan Province, China

Coronaviruses (CoVs) pose a threat to human health globally, as highlighted by severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and the COVID-19 pandemic. Bats from the Greater Mekong Subregion (GMS) are an important natural reservoir for CoVs. Here we report the differential prevalence of CoVs in bats within Yunnan Province across biological and ecological variables. We also show the coexistence of CoVs in individual bats and identify an additional putative host for SARS-related CoV, with higher dispersal capacity than other known hosts. Notably, 11 SARS-related coronaviruses (SARSr-CoVs) were discovered in horseshoe bats (family Rhinolophidae) and a Chinese water myotis bat (Myotis laniger) by pan-CoV detection and Illumina sequencing. Our findings facilitate an understanding of the fundamental features of the distribution and circulation of CoVs in nature as well as zoonotic spillover risk in the One health framework.

The links between dietary diversity and RNA virus diversity harbored by the great evening bat (Ia io)

BACKGROUND

Predator‒prey interactions and their dynamic changes provide frequent opportunities for viruses to spread among organisms and thus affect their virus diversity. However, the connections between dietary diversity and virus diversity in predators have seldom been studied. The avivorous bats, Ia io, show a seasonal pattern of dietary diversity. Although most of them primarily prey on insects in summer, they mainly prey on nocturnally migrating birds in spring and autumn.

RESULTS

In this study, we characterized the RNA virome of three populations of I. io in Southwest China during summer and autumn using viral metatranscriptomic sequencing. We also investigated the relationships between dietary diversity and RNA virus diversity by integrating DNA metabarcoding and viral metatranscriptomic sequencing techniques at the population level of I. io. We found 55 known genera belonging to 35 known families of RNA viruses. Besides detecting mammal-related viruses, which are the usual concern, we also found a high abundance of insect-related viruses and some bird-related viruses. We found that insect-related viruses were more abundant in summer, while the bird-related viruses were predominantly detected in autumn, which might be caused by the seasonal differences in prey selection by I. io. Additionally, a significant positive correlation was identified between prey diversity and total virus diversity. The more similar the prey composition, the more similar the total virus composition and the higher the count of potential new viruses. We also found that the relative abundance of Picornaviridae increased with increasing prey diversity and body mass.

CONCLUSIONS

In this study, significant links were found between RNA virus diversity and dietary diversity of I. io. The results implied that dynamic changes in predator-prey interactions may facilitate frequent opportunities for viruses to spread among organisms. Video Abstract.

Bat Ecology and Microbiome of the Gut: A Narrative Review of Associated Potentials in Emerging and Zoonotic Diseases

In this review, we tentatively tried to connect the most recent findings on the bat microbiome and to investigate on their microbial communities, that may vary even in conspecific hosts and are influenced by host physiology, feeding behavior and diet, social interactions, but also by habitat diversity and climate change. From a conservation perspective, understanding the potentially negative and indirect effects of habitat destruction on animal microbiota can also play a crucial role in the conservation and management of the host itself. According to the One Health concept, which recognizes an interdependence between humans, animals, and the environment, bat microbiota represents an indicator of host and environmental health, besides allowing for evaluation of the risk of emerging infectious diseases. We noticed that a growing number of studies suggest that animal microbiota may respond in various ways to changes in land use, particularly when such changes lead to altered or deficient food resources. We have highlighted that the current literature is strongly focused on the initial phase of investigating the microbial communities found in Chiroptera from various habitats. However, there are gaps in effectively assessing the impacts of pathogens and microbial communities in general in animal conservation, veterinary, and public health. A deeper understanding of bat microbiomes is paramount to the implementation of correct habitat and host management and to the development of effective surveillance protocols worldwide.

Complete mitochondrial genome of Penicillidia dufourii (Diptera: Hippoboscoidea: Nycteribiidae) and phylogenetic relationship

Penicillidia dufourii (Westwood 1834) is a specialized parasite categorized under family Nycteribiidae that prefers to parasitize the body surface of various bats under the genus Myotis. Many species of the family Nycteribiidae are carriers of various pathogens; however, research on P. dufourii remains scarce, and studies on its molecular identification and population genetic structure are still lacking. In this study, the complete mitochondrial genome of P. dufourii was elucidated for the first time using Illumina sequencing. The mitochondrial genome is 15,354 bp in size and encodes approximately 37 genes, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region. Analysis of 13 protein-coding genes revealed that UUA, UCA, CGA, and GGA were the most common codons, while nad4L had the fastest evolutionary rate and cox1 the slowest. Phylogenetic analysis based on the mitochondrial genome indicated that P. dufourii is clustered with other species of the family Nycteribiidae and is most closely related to Nycteribia parvula and Phthiridium szechuanum.

Gastrointestinal parasitic helminths of bats from a cave in Luzon Island, Philippines

Bats are often associated with several zoonotic diseases, including helminth infections. Despite their potential detrimental effects on both human and bat populations, information on helminth parasites of Philippine bats remains scarce. Here, we identify gastrointestinal helminths parasitizing bats collected from a cave complex in Cavinti, Laguna Province, Philippines, determine their prevalence (P) and mean intensity (MI), and investigate relationship of helminth prevalence and intensity with bat host characteristics including sex, diet, age, and roosting habit. We isolated 581 individuals of helminths representing six taxa (three trematodes, two nematodes, one cestode) from the gastrointestinal tract of sampled bats. Helminths were observed in 82 out of 172 bats captured (P = 47.67%), with Miniopteruspaululus having the highest infection rate (P = 91.3%) and highest MI (18 ± 4.5/infected bat). Helminths parasitizing endemic bat species from the Philippines, such as Rhinolophus rufus, Rhinolophus inops, Hipposideros pygmaeus, and Ptenochirus jagori were reported here for the first time. We provide new host records for other helminth species and report the presence of two parasites, Plagiorchis sp. and Toxocara sp., known for their zoonotic potential. These data will contribute to efforts in identifying parasites and diseases harbored by bats in the country and develop additional conservation measures for bats.

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.

Phylogenetic analyses reveal bat communities in Northwestern Mexico harbor a high diversity of novel cryptic ectoparasite species

Parasites are integral parts of ecosystem function and important drivers of evolutionary processes. Characterizing ectoparasite diversity is fundamental to studies of host-parasite interactions, evolution, and conservation, and also for understanding emerging disease threats for some vector borne pathogens. With more than 1400 species, bats represent the second most speciose mammalian clade, but their ectoparasite fauna are poorly known for most species. We sequenced mitochondrial Cytochrome Oxidase C subunit I and nuclear 18S ribosomal gene fragments, and used Bayesian phylogenetic analyses to characterize ectoparasite taxon identity and diversity for 17 species of parasitized bats sampled along the Baja California peninsula and in Northwestern Mexico. The sequence data revealed multiple novel lineages of bat bugs (Cimicidae), flies (Nycteribiidae and Streblidae), and ticks (Argasidae). Within families, the new linages showed more than 10% sequence divergence, which is consistent with separation at least at the species level. Both families of bat flies showed host specificity, particularly on Myotis species. We also identified new records for the Baja peninsula of one tick (Carios kelleyi), and of five Streblid bat fly species. One Nycteribiid bat fly haplotype from Pallid bat (Antrozous pallidus) hosts was found throughout the peninsula, suggesting potential long distance co-dispersal with hosts. Different bat bug and tick communities were found in the north and south of the peninsula. This study is the first systematic survey of bat ectoparasites in the Baja California peninsula, revealing novel lineages that are highly genetically differentiated from other parts of North America. For some ectoparasite species, haplotype distributions may reflect patterns of bat migration. This work is a first step in characterizing ectoparasite diversity over the Baja California peninsula, and understanding how ecological and evolutionary interactions shape bat ectoparasite communities among host species in different parts of their ranges.

A Look inside the Replication Dynamics of SARS-CoV-2 in Blyth's Horseshoe Bat (Rhinolophus lepidus) Kidney Cells

Bats are considered the natural reservoir of numerous emerging viruses such as severe acute respiratory syndrome coronaviruses (SARS-CoVs). There is a need for immortalized bat cell lines to culture and investigate the pathogenicity, replication kinetics, and evolution of emerging coronaviruses. We illustrate the susceptibility and permissiveness of a spontaneously immortalized kidney cell line (Rhileki) from Blyth's horseshoe bat (R. lepidus) to SARS-CoV-2 virus, including clinical isolates, suggesting a possible virus-host relationship. We were able to observe limited SARS-CoV-2 replication in Rhileki cells compared with simian VeroE6 cells. Slower viral replication in Rhileki cells was indicated by higher ct values (RT-PCR) at later time points of the viral culture and smaller foci (foci forming assay) compared with those of VeroE6 cells. With this study we demonstrate that SARS-CoV-2 replication is not restricted to R. sinicus and could include more Rhinolophus species. The establishment of a continuous Rhinolophus lepidus kidney cell line allows further characterization of SARS-CoV-2 replication in Rhinolophus bat cells, as well as isolation attempts of other bat-borne viruses. IMPORTANCE The current COVID-19 pandemic demonstrates the significance of bats as reservoirs for severe viral diseases. However, as bats are difficult to establish as animal models, bat cell lines can be an important proxy for the investigation of bat-virus interactions and the isolation of bat-borne viruses. This study demonstrates the susceptibility and permissiveness of a continuous kidney bat cell line to SARS-CoV-2. This does not implicate the bat species Rhinolophus lepidus, where these cells originate from, as a potential reservoir, but emphasizes the usefulness of this cell line for further characterization of SARS-CoV-2. This can lead to a better understanding of emerging viruses that could cause significant disease in humans and domestic animals.

Increasing risks for emerging infectious diseases within a rapidly changing High Asia

The cold and arid mountains and plateaus of High Asia, inhabited by a relatively sparse human population, a high density of livestock, and wildlife such as the iconic snow leopard Panthera uncia, are usually considered low risk for disease outbreaks. However, based on current knowledge about drivers of disease emergence, we show that High Asia is rapidly developing conditions that favor increased emergence of infectious diseases and zoonoses. This is because of the existing prevalence of potentially serious pathogens in the system; intensifying environmental degradation; rapid changes in local ecological, socio-ecological, and socio-economic factors; and global risk intensifiers such as climate change and globalization. To better understand and manage the risks posed by diseases to humans, livestock, and wildlife, there is an urgent need for establishing a disease surveillance system and improving human and animal health care. Public health must be integrated with conservation programs, more ecologically sustainable development efforts and long-term disease surveillance.

Counterintuitive scaling between population abundance and local density: Implications for modelling transmission of infectious diseases in bat populations

Models of host-pathogen interactions help to explain infection dynamics in wildlife populations and to predict and mitigate the risk of zoonotic spillover. Insights from models inherently depend on the way contacts between hosts are modelled, and crucially, how transmission scales with animal density. Bats are important reservoirs of zoonotic disease and are among the most gregarious of all mammals. Their population structures can be highly heterogeneous, underpinned by ecological processes across different scales, complicating assumptions regarding the nature of contacts and transmission. Although models commonly parameterise transmission using metrics of total abundance, whether this is an ecologically representative approximation of host-pathogen interactions is not routinely evaluated. We collected a 13-month dataset of tree-roosting Pteropus spp. from 2,522 spatially referenced trees across eight roosts to empirically evaluate the relationship between total roost abundance and tree-level measures of abundance and density-the scale most likely to be relevant for virus transmission. We also evaluate whether roost features at different scales (roost level, subplot level, tree level) are predictive of these local density dynamics. Roost-level features were not representative of tree-level abundance (bats per tree) or tree-level density (bats per m² or m³ ), with roost-level models explaining minimal variation in tree-level measures. Total roost abundance itself was either not a significant predictor (tree-level 3D density) or only weakly predictive (tree-level abundance). This indicates that basic measures, such as total abundance of bats in a roost, may not provide adequate approximations for population dynamics at scales relevant for transmission, and that alternative measures are needed to compare transmission potential between roosts. From the best candidate models, the strongest predictor of local population structure was tree density within roosts, where roosts with low tree density had a higher abundance but lower density of bats (more spacing between bats) per tree. Together, these data highlight unpredictable and counterintuitive relationships between total abundance and local density. More nuanced modelling of transmission, spread and spillover from bats likely requires alternative approaches to integrating contact structure in host-pathogen models, rather than simply modifying the transmission function.

Virome Analysis of Signal Crayfish (Pacifastacus leniusculus) along Its Invasion Range Reveals Diverse and Divergent RNA Viruses

Crayfish are a keystone species of freshwater ecosystems and a successful invasive species. However, their pathogens, including viruses, remain understudied. The aim of this study was to analyze the virome of the invasive signal crayfish (Pacifastacus leniusculus) and to elucidate the potential differences in viral composition and abundance along its invasion range in the Korana River, Croatia. By the high-throughput sequencing of ribosomal RNA, depleted total RNA isolated from the crayfish hepatopancreas, and subsequent sequence data analysis, we identified novel and divergent RNA viruses, including signal crayfish-associated reo-like, hepe-like, toti-like, and picorna-like viruses, phylogenetically related to viruses previously associated with crustacean hosts. The patterns of reads abundance and calculated nucleotide diversities of the detected viral sequences varied along the invasion range. This could indicate the possible influence of different factors and processes on signal crayfish virome composition: e.g., the differences in signal crayfish population density, the non-random dispersal of host individuals from the core to the invasion fronts, and the transfer of viruses from the native co-occurring and phylogenetically related crayfish species. The study reveals a high, previously undiscovered diversity of divergent RNA viruses associated with signal crayfish, and sets foundations for understanding the potential risk of virus transmissions as a result of this invader's dispersal.

Molecular identification and genetic diversity of Bartonella spp. in 24 bat species from Thailand

The study of bacterial zoonoses has been under-pursued despite the fact that bacteria cause the majority of zoonotic diseases, of which 70% have a wildlife origin. More Bartonella species are being identified as the cause of human diseases, and several of them have been linked to domestic and wild animals. Bats are outstanding reservoirs for Bartonella species because of their wide distribution, mobility, roosting behaviour, and long life span. Here, we carried out a PCR-based survey on bats that were collected from 19 sampling sites in eight provinces of Thailand from February 2018 to April 2021. Bartonella infection was investigated in a total of 459 bats that belong to 24 different bat species (21 species of which had never been previously studied in Thailand). PCR diagnostics revealed that 115 out of 459 (25.5%) blood samples tested positive for Bartonella. The nucleotide identities of the Bartonella 16S rRNA sequences in this study were between 95.78-99.66% identical to those of known zoonotic species (Bartonella ancashensis, Bartonella henselae, Bartonella bacilliformis and Bartonella australis) as well as to an unidentified Bartonella spp. In addition, the citrate synthase (gltA) and RNA polymerase-beta subunit (rpoB) genes of Bartonella were sequenced and analyzed in positive samples. The gltA and rpoB gene sequences from Hipposideros gentilis and Rhinolophus coelophyllus bat samples showed low nucleotide identity (<95%) compared to those of the currently deposited sequences in the GenBank database, indicating the possibility of new Bartonella species. The phylogenetic inference and genetic diversity were generated and indicated a close relationship with other Bartonella species previously discovered in Asian bats. Overall, the current study demonstrates the primary evidence pointing to a potential novel Bartonella species in bats. This discovery also contributes to our current understanding of the geographical distribution, genetic diversity, and host ranges of bat-related Bartonella.

Habitat fragmentation and vegetation structure impact gastrointestinal parasites of small mammalian hosts in Madagascar

Deleterious effects of habitat loss and fragmentation on biodiversity have been demonstrated in numerous taxa. Although parasites represent a large part of worldwide biodiversity, they are mostly neglected in this context. We investigated the effects of various anthropogenic environmental changes on gastrointestinal parasite infections in four small mammal hosts inhabiting two landscapes of fragmented dry forest in northwestern Madagascar. Coproscopical examinations were performed on 1,418 fecal samples from 903 individuals of two mouse lemur species, Microcebus murinus (n = 199) and M. ravelobensis (n = 421), and two rodent species, the native Eliurus myoxinus (n = 102) and the invasive Rattus rattus (n = 181). Overall, sixteen parasite morphotypes were detected and significant prevalence differences between host species regarding the most common five parasites may be explained by parasite-host specificity or host behavior, diet, and socioecology. Ten host- and habitat-related ecological variables were evaluated by generalized linear mixed modeling for significant impacts on the prevalence of the most abundant gastrointestinal parasites and on gastrointestinal parasite species richness (GPSR). Forest maturation affected homoxenous parasites (direct life cycle) by increasing Lemuricola, but decreasing Enterobiinae gen. sp. prevalence, while habitat fragmentation and vegetation clearance negatively affected the prevalence of parasites with heterogenic environment (i.e., Strongyloides spp.) or heteroxenous (indirect cycle with intermediate host) cycles, and consequently reduced GPSR. Forest edges and forest degradation likely change abiotic conditions which may reduce habitat suitability for soil-transmitted helminths or required intermediate hosts. The fragility of complex parasite life cycles suggests understudied and potentially severe effects of decreasing habitat quality by fragmentation and degradation on hidden ecological networks that involve parasites. Since parasites can provide indispensable ecological services and ensure stability of ecosystems by modulating animal population dynamics and nutrient pathways, our study underlines the importance of habitat quality and integrity as key aspects of conservation.

Niche theory-based modeling of assembly processes of viral communities in bats

Understanding the assembly processes of symbiont communities, including viromes and microbiomes, is important for improving predictions on symbionts' biogeography and disease ecology. Here, we use phylogenetic, functional, and geographic filters to predict the similarity between symbiont communities, using as a test case the assembly process in viral communities of Mexican bats. We construct generalized linear models to predict viral community similarity, as measured by the Jaccard index, as a function of differences in host phylogeny, host functionality, and spatial co-occurrence, evaluating the models using the Akaike information criterion. Two model classes are constructed: a "known" model, where virus-host relationships are based only on data reported in Mexico, and a "potential" model, where viral reports of all the Americas are used, but then applied only to bat species that are distributed in Mexico. Although the "known" model shows only weak dependence on any of the filters, the "potential" model highlights the importance of all three filter types-phylogeny, functional traits, and co-occurrence-in the assemblage of viral communities. The differences between the "known" and "potential" models highlight the utility of modeling at different "scales" so as to compare and contrast known information at one scale to another one, where, for example, virus information associated with bats is much scarcer.

Host specificity of Hepatocystis infection in short-nosed fruit bats (Cynopterus brachyotis) in Singapore

Haemosporidians infect a wide diversity of bat genera and species, yet little is known about their transmission cycles or epidemiology. Though several recent studies have focused on the genus Hepatocystis, an Old World parasite primarily infecting bats, monkeys, and squirrels, this group is still understudied with little known about its transmission and molecular ecology. These parasites lack an asexual erythrocytic stage, making them unique from the Plasmodium vertebrate life cycle. In this study, we detected a prevalence of 31% of Hepatocystis in short-nosed fruit bats (Cynopterus brachyotis) in Singapore. Phylogenetic reconstruction with a partial cytochrome b sequence revealed a monophyletic group of Hepatocystis from C. brachyotis in Malaysia, Singapore, and Thailand. There was no relationship with infection and bat age, sex, location, body condition or monsoon season. The absence of this parasite in the five other bat species sampled in Singapore indicates this Hepatocystis species may be host restricted.

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A bat haemosporidian (Hepatocystis) was detected in short nose fruit bats (Cynopterus brachyotis) in Singapore.

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Infection was not associated with bat age, sex, sample location, body condition or monsoon season.

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Infection was detected in only one bat species, indicating this Hepatocystis species may be host specific.

Rovie-Ryan J. Exposure to Zoonotic West Nile Virus in Long-Tailed Macaques and Bats in Peninsular Malaysia

Simple Summary

The role of wildlife animals, such as macaques and bats, in the spreading and maintenance of deadly zoonotic pathogens in nature are documented in several studies. The present study substantially highlights the first evidence of West Nile Virus (WNV) infection, a mosquito borne virus in the Malaysian macaques and bats. Of the 81 macaques sampled, 24 of the long-tailed macaques were seropositive to WNV, indicating that they were exposed to the virus in the past. The long-tailed macaques were found in the mangrove forests located in the Central, Southern, and West Peninsular Malaysia. Meanwhile, five out of 41 bats (Lesser Short-nosed Fruit Bats, Lesser Sheath-tailed Bats, and Thai Horseshoe Bats) that were found in the caves from Northern Peninsular Malaysia showed susceptibility to WNV. Therefore, a constant bio surveillance of WNV in the wildlife in Malaysia is a proactive attempt. This study was aligned with the Malaysian government’s mission under the Malaysia Strategy for Emerging Diseases and Public Health Emergencies (MYSED) II (2017–2021) and the Ministry of Health priorities in order to enhance the regional capability to rapidly and accurately survey, detect, diagnose, and report outbreaks of pathogens and diseases of security concern.

Abstract

The role of wildlife such as wild birds, macaques, and bats in the spreading and maintenance of deadly zoonotic pathogens in nature have been well documented in many parts of the world. One such pathogen is the mosquitoes borne virus, namely the West Nile Virus (WNV). Previous research has shown that 1:7 and 1:6 Malaysian wild birds are WNV antibody and RNA positive, respectively, and bats in North America may not be susceptible to the WNV infection. This study was conducted to determine the status of WNV in Malaysian macaques and bats found in mangrove forests and caves, respectively. Archive sera and oropharyngeal swabs from long-tailed macaques were subjected to the antibody detection using WNV competitive enzyme-linked immunosorbent assay (c-ELISA) and WNV RNA using RT-PCR, respectively, while the archive oropharyngeal and rectal swabs from bats were subjected to RT-PCR without serological analysis due to the unavailability of serum samples. The analysis revealed a WNV seropositivity of 29.63% (24/81) and none of the macaques were positive for WNV RNA. Meanwhile, 12.2% (5/41) of the bats from Pteropodidae, Emballonuridae, and Rhinolophidae families tested positive for WNV RNA. Here, we show a high WNV antibody prevalence in macaques and a moderate WNV RNA in various Malaysian bat species, suggesting that WNV circulates through Malaysian wild animals and Malaysian bat species may be susceptible to the WNV infection.

Effects of latitude, host body size, and host trophic guild on patterns of diversity of helminths associated with humans, wild and domestic mammals of Mexico

Parasites are strictly associated with their hosts and present a great diversity of life histories, often resulting in different diversity patterns than those observed in free-living species. However, ecological approaches have detected that, in some cases, mammal-associated helminths respond similarly to non-parasitic species in terms of diversity patterns. Using 2200 recorded interactions, we analysed the diversity patterns of helminths (Acanthocephala, Nematoda and Platyhelminthes) harbored by humans, wild and domestic mammals of Mexico, depending on latitude, host body mass and trophic guild (carnivore, herbivore, insectivore, omnivore), considering helminth richness and average taxonomic distinctness, and host phylogenetic diversity and phylogenetic clustering. Latitude was positively correlated with the average taxonomic distinctness encompassing the three parasite phyla and nematodes. Northern latitudes had less taxonomically related parasite assemblages. Host body mass had a significant negative relationship with the average taxonomic distinctness of acanthocephalans and the richness of helminths associated to wild hosts. The omnivore hosts had greater parasite richness, while insectivores had a less taxonomically related parasite assemblage and herbivores had a more heterogeneous parasite assemblage. Our results highlight the importance of incorporating different dimensions of diversity, such as average taxonomic distinctness and to consider the composition of parasite assemblages to better understand their diversity patterns.

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Four diversity measures were used to describe diversity patterns of helminths.

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Latitude was positively correlated with helminth average taxonomic distinctness.

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Host body mass was negatively related with the helminth richness of wildlife hosts.

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Helminth sets of omnivore hosts were richer in parasite species.

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Helminth sets of insectivore hosts had a wider taxonomic breadth.

Bats as putative Zaire ebolavirus reservoir hosts and their habitat suitability in Africa

The genus Ebolavirus comprises some of the deadliest viruses for primates and humans and associated disease outbreaks are increasing in Africa. Different evidence suggests that bats are putative reservoir hosts and play a major role in the transmission cycle of these filoviruses. Thus, detailed knowledge about their distribution might improve risk estimations of where future disease outbreaks might occur. A MaxEnt niche modelling approach based on climatic variables and land cover was used to investigate the potential distribution of 9 bat species associated to the Zaire ebolavirus. This viral species has led to major Ebola outbreaks in Africa and is known for causing high mortalities. Modelling results suggest suitable areas mainly in the areas near the coasts of West Africa with extensions into Central Africa, where almost all of the 9 species studied find suitable habitat conditions. Previous spillover events and outbreak sites of the virus are covered by the modelled distribution of 3 bat species that have been tested positive for the virus not only using serology tests but also PCR methods. Modelling the habitat suitability of the bats is an important step that can benefit public information campaigns and may ultimately help control future outbreaks of the disease.

Pathogens Shape Sex Differences in Mammalian Aging

Understanding the origin of sex differences in lifespan and aging patterns remains a salient challenge in both biogerontology and evolutionary biology. Different factors have been studied but the potential influence of pathogens has never been investigated. Sex differences, especially in hormones and resource allocation, generate a differential response to pathogens and thereby shape sex differences in lifespan or aging. We provide an integrative framework linking host pathogenic environment with both sex-specific selections on immune performance and mortality trajectories. We propose future directions to fill existing knowledge gaps about mechanisms that link sex differences, not only to exposition and sensitivity to pathogens, but also to mortality patterns, whilst emphasizing the urgent need to consider the role of sex in medicine.

Years of research in biomedical sciences have revealed that sex-specific immune responses to pathogens can be associated with sex-specific consequences on health.

These effects partly account for the observed sex gap in lifespan, leading women to be longer-lived than males in human populations.

Sexual selection exerted on males and the pathogenic environment may explain, at least partly, the sex-difference in lifespan generally observed across mammalian populations.

The influence of bat ecology on viral diversity and reservoir status

Repeated emergence of zoonotic viruses from bat reservoirs into human populations demands predictive approaches to preemptively identify virus-carrying bat species. Here, we use machine learning to examine drivers of viral diversity in bats, determine whether those drivers depend on viral genome type, and predict undetected viral carriers. Our results indicate that bat species with longer life spans, broad geographic distributions in the eastern hemisphere, and large group sizes carry more viruses overall. Life span was a stronger predictor of deoxyribonucleic acid viral diversity, while group size and family were more important for predicting ribonucleic acid viruses, potentially reflecting broad differences in infection duration. Importantly, our models predict 54 bat species as likely carriers of zoonotic viruses, despite not currently being considered reservoirs. Mapping these predictions as a proportion of local bat diversity, we identify global regions where efforts to reduce disease spillover into humans by identifying viral carriers may be most productive.

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.

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.

Viral networks and detection of potential zoonotic viruses in bats and rodents: A worldwide analysis

Bats and rodents are recognized to host a great diversity of viruses and several important viral zoonoses, but how this viral diversity is structured and how viruses are connected, shared and distributed among host networks is not well understood. To address this gap in knowledge, we compared the associative capacity of the host-virus networks in rodents and bats with the identification of those viruses with zoonotic potential. A virus database, detected by molecular methods, was constructed in the two taxonomic groups. We compiled 5,484 records: 825 in rodents and 4,659 in bats. We identified a total of 173 and 166 viruses, of which 53 and 40 are zoonotic viruses, in rodents and bats, respectively. Based on a network theory, a non-directed bipartite host-virus network was built for each group. Subsequently, the networks were collapsed to represent the connections among hosts and viruses. We identified both discrete and connected communities. We observed a greater degree of connectivity in bat viruses and more discrete communities in rodents. The Coronaviridae recorded in bats have the highest values of degree, betweenness and closeness centralities. In rodents, higher degree positions were distributed homogeneously between viruses and hosts. At least in our database, a higher proportion of rodent viruses were zoonotic. Rodents should thus not be underestimated as important reservoirs of zoonotic disease. We found that viruses were more frequently shared among bats than in rodents. Network theory can reveal some macroecological patterns and identify risks that were previously unrecognized. For example, we found that parvovirus in megabats and Gbagroube virus in rodents may represent a zoonotic risk due to the proximity to humans and other zoonotic viruses. We propose that epidemiological surveillance programmes should consider the connectivity of network actors as a measure of the risks of dispersion and transmission.

Bat Flies and Their Microparasites: Current Knowledge and Distribution

Bats are the second most diverse mammalian group, playing keystone roles in ecosystems but also act as reservoir hosts for numerous pathogens. Due to their colonial habits which implies close contacts between individuals, bats are often parasitized by multiple species of micro- and macroparasites. The particular ecology, behavior, and environment of bat species may shape patterns of intra- and interspecific pathogen transmission, as well as the presence of specific vectorial organisms. This review synthetizes information on a multi-level parasitic system: bats, bat flies and their microparasites. Bat flies (Diptera: Nycteribiidae and Streblidae) are obligate, hematophagous ectoparasites of bats consisting of ~500 described species. Diverse parasitic organisms have been detected in bat flies including bacteria, blood parasites, fungi, and viruses, which suggest their vectorial potential. We discuss the ecological epidemiology of microparasites, their potential physiological effects on both bats and bat flies, and potential research perspectives in the domain of bat pathogens. For simplicity, we use the term microparasite throughout this review, yet it remains unclear whether some bacteria are parasites or symbionts of their bat fly hosts.

Phylogeny matters: revisiting 'a comparison of bats and rodents as reservoirs of zoonotic viruses'

Diseases emerging from wildlife have been the source of many major human outbreaks. Predicting key sources of these outbreaks requires an understanding of the factors that explain pathogen diversity in reservoir species. Comparative methods are powerful tools for understanding variation in pathogen diversity and rely on correcting for phylogenetic relatedness among reservoir species. We reanalysed a previously published dataset, examining the relative effects of species' traits on patterns of viral diversity in bats and rodents. We expanded on prior work by using more highly resolved phylogenies for bats and rodents and incorporating a phylogenetically controlled principal components analysis. For rodents, sympatry and torpor use were important predictors of viral richness and, as previously reported, phylogeny had minimal impact in models. For bats, in contrast to prior work, we find that phylogeny does have an effect in models. Patterns of viral diversity in bats were related to geographical distribution (i.e. latitude and range size) and life history (i.e. lifespan, body size and birthing frequency). However, the effects of these predictors were marginal relative to citation count, emphasizing that the ability to accurately assess reservoir status largely depends on sampling effort and highlighting the need for additional data in future comparative studies.

The Impact of Global Environmental Changes on Infectious Disease Emergence with a Focus on Risks for Brazil

Environmental changes have a huge impact on the emergence and reemergence of certain infectious diseases, mostly in countries with high biodiversity and serious unresolved environmental, social, and economic issues. This article summarizes the most important findings with special attention to Brazil and diseases of present public health importance in the country such as Chikungunya, dengue fever, yellow fever, Zika, hantavirus pulmonary syndrome, leptospirosis, leishmaniasis, and Chagas disease. An extensive literature review revealed a relationship between infectious diseases outbreaks and climate change events (El Niño, La Niña, heatwaves, droughts, floods, increased temperature, higher rainfall, and others) or environmental changes (habitat fragmentation, deforestation, urbanization, bushmeat consumption, and others). To avoid or control outbreaks, integrated surveillance systems and effective outreach programs are essential. Due to strong global and local influence on emergence of infectious diseases, a more holistic approach is necessary to mitigate or control them in low-income nations.

Hidden diversity and evolution of viruses in market fish

Aquaculture is the fastest growing industry worldwide. Aquatic diseases have had enormous economic and environmental impacts in the recent past and the emergence of new aquatic pathogens, particularly viruses, poses a continuous threat. Nevertheless, little is known about the diversity, abundance and evolution of fish viruses. We used a meta-transcriptomic approach to help determine the virome of seemingly healthy fish sold at a market in Sydney, Australia. Specifically, by identifying and quantifying virus transcripts we aimed to determine (i) the abundance of viruses in market fish, (ii) test a key component of epidemiological theory that large and dense host populations harbour a greater number of viruses compared to their more solitary counterparts and (iii) reveal the relative roles of virus–host co-divergence and cross-species transmission in the evolution of fish viruses. The species studied comprised both shoaling fish—eastern sea garfish (Hyporhamphus australis) and Australasian snapper (Chrysophrys auratus)—and more solitary fish—eastern red scorpionfish (Scorpaena jacksoniensis) and largetooth flounder (Pseudorhombus arsius). Our analysis identified twelve potentially novel viruses, eight of which were likely vertebrate-associated across four viral families and that exhibited frequent cross-species transmission. Notably, the most solitary of the fish species studied, the largetooth flounder, harboured the least number of viruses while eastern sea garfish, a densely shoaling fish, had the highest number of viruses. These results support the emerging view that fish harbour a large and largely uncharacterised virome.

Distribution of bat-borne viruses and environment patterns

Environmental modifications are leading to biodiversity changes, loss and habitat disturbance. This in turn increases contacts between wildlife and hence the risk of transmission and emergence of zoonotic diseases. We analyzed the environment and land use using remote spatial data around the sampling locations of bats positive for coronavirus (21 sites) and astrovirus (11 sites) collected in 43 sites. A clear association between viruses and hosts was observed. Viruses associated to synanthropic bat genera, such as Myotis or Scotophilus were associated to highly transformed habitats with human presence while viruses associated to fruit bat genera were correlated with natural environments with dense forest, grassland areas and regions of high elevation. In particular, group C betacoronavirus were associated with mosaic habitats found in anthropized environments.

Viral Richness is Positively Related to Group Size, but Not Mating System, in Bats

Characterizing host traits that influence viral richness and diversification is important for understanding wildlife pathogens affecting conservation and/or human health. Behaviors that affect contact rates among hosts could be important for viral diversification because more frequent intra- and inter-specific contacts among hosts should increase the potential for viral diversification within host populations. We used published data on bats to test the contact-rate hypothesis. We predicted that species forming large conspecific groups, that share their range with more heterospecifics (i.e., sympatry), and with mating systems characterized by high contact rates (polygynandry: multi-male/multi-female), would host higher viral richness than species with small group sizes, lower sympatry, or low contact-rate mating systems (polygyny: single male/multi-female). Consistent with our hypothesis and previous research, viral richness was positively correlated with conspecific group size although the relationship plateaued at group sizes of approximately several hundred thousand bats. This pattern supports epidemiological theory that, up to a point, larger groups have higher contact rates, greater likelihood of acquiring and transmitting viruses, and ultimately greater potential for viral diversification. However, contrary to our hypothesis, there was no effect of sympatry on viral richness and no difference in viral richness between mating systems. We also found no residual effect of host phylogeny on viral richness, suggesting that closely related species do not necessarily host similar numbers of viruses. Our results support the contact-rate hypothesis that intra-specific viral transmission can enhance viral diversification within species and highlight the influence of host group size on the potential of viruses to propagate within host populations.

Virome analysis of two sympatric bat species (Desmodus rotundus and Molossus molossus) in French Guiana

Environmental disturbances in the Neotropics (e.g., deforestation, agriculture intensification, urbanization) contribute to an increasing risk of cross-species transmission of microorganisms and to disease outbreaks due to changing ecosystems of reservoir hosts. Although Amazonia encompasses the greatest diversity of reservoir species, the outsized viral population diversity (virome) has yet to be investigated. Here, through a metagenomic approach, we identified 10,991 viral sequences in the saliva and feces of two bat species, Desmodus rotundus (hematophagous), trapped in two different caves surrounded by primary lowland forest, and Molossus molossus (insectivorous), trapped in forest and urban habitats. These sequences are related to 51 viral families known to infect a wide range of hosts (i.e., bacteria, plants, insects and vertebrates). Most viruses detected reflected the diet of bat species, with a high proportion of plant and insect-related viral families for M. molossus and a high proportion of vertebrate-related viral families for D. rotundus, highlighting its influence in shaping the viral diversity of bats. Lastly, we reconstructed the phylogenetic relationships for five vertebrate-related viral families (Nairoviridae, Circoviridae, Retroviridae, Herpesviridae, Papillomaviridae). The results showed highly supported clustering with other viral sequences of the same viral family hosted by other bat species, highlighting the potential association of viral diversity with the host’s diet. These findings provide significant insight into viral bat diversity in French Guiana belonging to the Amazonian biome and emphasize that habitats and the host’s dietary ecology may drive the viral diversity in the bat communities investigated.

Understanding the interaction between henipaviruses and their natural host, fruit bats: Paving the way toward control of highly lethal infection in humans

Hendra virus and Nipah virus (NiV) are highly pathogenic zoonotic paramyxoviruses, from henipavirus genus, that have emerged in late 1990s in Australia and South-East Asia, respectively. Since their initial identification, numerous outbreaks have been reported, affecting both domestic animals and humans, and multiple rounds of person-to-person NiV transmission were observed. Widely distributed fruit bats from Pteropodidae family were found to be henipavirus natural reservoir. Numerous studies have reported henipavirus seropositivity in pteropid bats, including bats in Africa, thus expanding notably the geographic distribution of these viruses. Interestingly, henipavirus infection in bats seems to be asymptomatic, in contrast to severe disease induced in numerous other mammals. Unique among the mammals by their ability to fly, these intriguing animals are natural reservoir for many other emerging and remerging viruses highly pathogenic for humans. This feature, combined with absence of clinical symptoms, has attracted the interest of scientific community to virus-bat interactions. Therefore, several bat genomes were sequenced and particularities of the bat immune system have been intensively analyzed during the last decade to understand their coexistence with viruses in the absence of disease. The peculiarities in inflammasome activation, a constitutive expression of interferon alpha, and some differences in adaptive immunity have been recently reported in fruit bats. Studies on virus-bat interactions have thus emerged as an exciting novel area of research that should shed new light on the mechanisms that regulate viral infection and may allow development of novel therapeutic approaches to control this highly lethal emerging infectious disease in humans.

Bats and Academics: How Do Scientists Perceive Their Object of Study?

Bats are associated with conflicting perceptions among humans, ranging from affection to disgust. If these attitudes can be associated with various factors among the general public (e.g. social norms, lack of knowledge), it is also important to understand the attitude of scientists who study bats. Such reflexive information on the researchers community itself could indeed help designing adequate mixed communication tools aimed at protecting bats and their ecosystems, as well as humans living in their vicinity that could be exposed to their pathogens. Thus, we conducted an online survey targeting researchers who spend a part of their research activity studying bats. Our aim was to determine (1) how they perceive their object of study, (2) how they perceive the representation of bats in the media and by the general population, (3) how they protect themselves against pathogen infections during their research practices, and (4) their perceptions of the causes underlying the decline in bat populations worldwide. From the 587 completed responses (response rate of 28%) having a worldwide distribution, the heterogeneity of the scientists' perception of their own object of study was highlighted. In the majority of cases, this depended on the type of research they conducted (i.e. laboratory versus field studies) as well as their research speciality. Our study revealed a high level of personal protection equipment being utilised against pathogens during scientific practices, although the role bats play as reservoirs for a number of emerging pathogens remains poorly known. Our results also disclosed the unanimity among specialists in attributing a direct role for humans in the global decline of bat populations, mainly via environmental change, deforestation, and agriculture intensification. Overall, the present study suggests the need for better communication regarding bats and their biology, their role within the scientific community, as well as in the general public population. As a consequence, increased knowledge regarding scientists' perceptions of bats should improve the role scientists play in influencing the perception of bats by the general public.

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.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-016-0802-1) contains supplementary material, which is available to authorized users.

Phylogenetic and geographic patterns of bartonella host shifts among bat species

The influence of factors contributing to parasite diversity in individual hosts and communities are increasingly studied, but there has been less focus on the dominant processes leading to parasite diversification. Using bartonella infections in bats as a model system, we explored the influence of three processes that can contribute to bartonella diversification and lineage formation: (1) spatial correlation in the invasion and transmission of bartonella among bats (phylogeography); (2) divergent adaptation of bartonellae to bat hosts and arthropod vectors; and (3) evolutionary codivergence between bats and bartonellae. Using a combination of global fit techniques and ancestral state reconstruction, we found that codivergence appears to be the dominant process leading to diversification of bartonella in bats, with lineages of bartonellae corresponding to separate bat suborders, superfamilies, and families. Furthermore, we estimated the rates at which bartonellae shift bat hosts across taxonomic scales (suborders, superfamilies, and families) and found that transition rates decrease with increasing taxonomic distance, providing support for a mechanism that can contribute to the observed evolutionary congruence between bats and their associated bartonellae. While bartonella diversification is associated with host sympatry, the influence of this factor is minor compared to the influence of codivergence and there is a clear indication that some bartonella lineages span multiple regions, particularly between Africa and Southeast Asia. Divergent adaptation of bartonellae to bat hosts and arthropod vectors is apparent and can dilute the overall pattern of codivergence, however its importance in the formation of Bartonella lineages in bats is small relative to codivergence. We argue that exploring all three of these processes yields a more complete understanding of bat-bartonella relationships and the evolution of the genus Bartonella, generally. Application of these methods to other infectious bacteria and viruses could uncover common processes that lead to parasite diversification and the formation of host-parasite relationships.

Optimizing Viral Discovery in Bats

Viral discovery studies in bats have increased dramatically over the past decade, yet a rigorous synthesis of the published data is lacking. We extract and analyze data from 93 studies published between 2007-2013 to examine factors that increase success of viral discovery in bats, and specific trends and patterns of infection across host taxa and viral families. Over the study period, 248 novel viruses from 24 viral families have been described. Using generalized linear models, at a study level we show the number of host species and viral families tested best explained number of viruses detected. We demonstrate that prevalence varies significantly across viral family, specimen type, and host taxonomy, and calculate mean PCR prevalence by viral family and specimen type across all studies. Using a logistic model, we additionally identify factors most likely to increase viral detection at an individual level for the entire dataset and by viral families with sufficient sample sizes. Our analysis highlights major taxonomic gaps in recent bat viral discovery efforts and identifies ways to improve future viral pathogen detection through the design of more efficient and targeted sample collection and screening approaches.

Bioecological Drivers of Rabies Virus Circulation in a Neotropical Bat Community

INTRODUCTION

In addition to the commonly accepted importance of the vampire bat in the maintenance and transmission of the rabies virus (RABV) in South America, RABV infection of other species is widely evidenced, challenging their role in the viral cycle.

METHODOLOGY / PRINCIPLES FINDINGS

To identify the bioecological drivers of RABV circulation in neotropical bat communities, we conducted a molecular and serological survey on almost 1,000 bats from 30 species, and a 4-year longitudinal survey in two colonies of vampire bats in French Guiana. RABV was molecularly detected in a common vampire and in a frugivorous bat. The sequences corresponded to haematophagous bat-related strains and were close to viruses circulating in the Brazilian Amazon region. Species' seroprevalence ranged from 0 to 20%, and the risk of seropositivity was higher in bats with a haematophagous diet, living in monospecific colonies and in dense forests. The longitudinal survey showed substantial temporal fluctuations, with individual waves of seroconversions and waning immunity. The high prevalences observed in bat communities, in most habitats and in species that do not share the same microhabitats and bioecological patterns, the temporal variations, and a rather short period of detectable antibodies as observed in recaptured vampires suggest (i) frequent exposure of animals, (ii) an ability of the infected host to control and eliminate the virus, (iii) more relaxed modes of exposure between bats than the commonly assumed infection via direct contact with saliva of infected animals, all of which should be further investigated.

CONCLUSIONS / SIGNIFICANCE

We hypothesize that RABV circulation in French Guiana is mainly maintained in the pristine forest habitats that may provide sufficient food resources to allow vampire bats, the main prevalent species, to survive and RABV to be propagated. However, on the forest edge and in disturbed areas, human activities may induce more insidious effects such as defaunation. One of the ecological consequences is the disappearance of resources for tertiary or secondary consumers. Populations of vampires may then shift to alternative resources such as cattle, domestic animals and humans. Therefore, a good forest status, allowing both a dilution effect in highly rich bat communities and the maintenance of large populations of medium-sized and large mammals used as prey by vampires, should prevent their migration to anthropized areas.

(macro-) Evolutionary ecology of parasite diversity: From determinants of parasite species richness to host diversification

The present review summarized the factors or determinants that may explain parasite diversity among host species and the consequences of this parasite diversity on the evolution of host-life history traits. As host-parasite interactions are asymmetrical exploited-exploiter relationships, ecological and epidemiological theories produce hypotheses to find the potential determinants of parasite species richness, while life-history theory helps for testing potential consequences on parasite diversity on the evolution of hosts. This review referred only to studies that have specifically controlled or took into account phylogenetic information illustrated with parasites of mammals. Several points needing more investigation were identified with a special emphasis to develop the metabolic theory of epidemiology.