Insectivorous bats carry host specific astroviruses and coronaviruses across different regions in Germany

Investigation of caliciviruses and astroviruses in Gabonese rodents: A possible influence of national and international trade on the spread of enteric viruses

Caliciviruses (Caliciviridae) and astroviruses (Astroviridae) are among the leading cause of non-bacterial foodborne disease and gastroenteritis in human. These non-enveloped RNA viruses infect a wide range of vertebrate species including rodents. Rodents are among the most important hosts of infectious diseases globally and are responsible for over 80 zoonotic pathogens that affect humans. Therefore, screening pathogens in rodents will be is necessary to prevent cross-species transmission to prevent zoonotic outbreaks. In the present study, we screened caliciviruses and astroviruses in order to describe their diversity and whether they harbor strains that can infect humans. RNA was then extracted from intestine samples of 245 rodents and retrotranscribed in cDNA to screen caliciviruses and astroviruses by PCRs. All the samples tested negative for caliciviruses and while astroviruses were detected in 18 (7.3%) samples of Rattus rattus species. Phylogenetic analyses based on the RdRp gene showed that all the sequences belonged to Mamastrovirus genus in which they were genetically related to R. rattus related AstVs previously detected in Gabon or in Rattus spp. AstV from Kenya and Asia. These findings suggested that transportation such as land and railway, as well national and international trade, are likely to facilitate spread of AstVs by the dissemination of rodents.

Presence of Alphacoronavirus in Tree- and Crevice-Dwelling Bats from Portugal

Coronaviruses (CoVs) are RNA viruses capable of infecting a wide range of hosts, including mammals and birds, and have caused significant epidemics such as the ongoing COVID-19 pandemic. Bats, the second most diverse mammalian order, are hosts for various CoVs due to their unique immune responses and ecological traits. This study investigates CoV prevalence in crevice- and tree-dwelling bats in Portugal, a country with limited prior research on bat CoVs. Using nested RT-PCR and sequencing, we screened 87 stool samples from bats, identifying one sample (1.15%) that was positive for Alphacoronavirus, belonging to Pipistrellus pipistrellus. Phylogenetic analysis revealed close genetic relationships with Alphacoronavirus strains from the same bat species in Europe. The low prevalence suggests habitat-specific differences in viral transmission, with cave-dwelling bats exhibiting higher CoV prevalence due to population density and behaviour. These findings underscore the necessity for sustained surveillance efforts aimed at comprehending CoV dynamics within bat populations, especially concerning the risk of spillover events and viral evolution. Vital to this understanding is the monitoring of bat migration patterns, which serves as a crucial tool for elucidating CoV ecology and epidemiology. Such efforts are essential for ongoing research endeavours aimed at mitigating the potential for future zoonotic disease outbreaks.

Diversity of astroviruses in wild animals in Yunnan province, China

BACKGROUND

Astroviruses (AstVs) are single-stranded RNA viruses that have been detected in a wide range of mammals and birds. They are associated with numerous interspecies transmissions and viral recombination events, posing a threat to human and animal health.

METHODS

We collected 1,333 samples from wild animals, including bats, rodents, wild boars, and birds, from various states and cities in the Yunnan Province, China, between 2020 and 2023 to investigate the presence of AstVs. AstVs were detected using a polymerase chain reaction targeting the RdRp gene. Finally, the Molecular Evolutionary Genetics Analysis software was used to construct the phylogenetic tree.

RESULTS

The overall positivity rate for AstVs was 7.12% in four species, indicating their widespread occurrence in the region. High genetic diversity among AstVs was observed in different animal species, suggesting the potential for interspecies transmission, particularly among rodents and birds. Additionally, we identified a novel AstV strain and, for the first time, provided information on the presence of bastroviruses in Yunnan, China.

CONCLUSIONS

The widespread distribution and high genetic diversity of AstVs, along with the observed potential for interspecies transmission, highlight the importance of further investigation and surveillance in the region. The findings emphasize the need for increased attention to AstVs and their potential impact on human and animal health in Yunnan and other regions.

Presence of coronaviruses in the common pipistrelle (P. pipistrellus) and Nathusius´ pipistrelle (P. nathusii) in relation to landscape composition

Changes in land use can modify habitat and roosting behaviour of bats, and therefore the transmission dynamics of viruses. Within bat roosts the density and contact rate among individuals increase and may facilitate the transmission of bat coronaviruses (CoVs). Landscape components supporting larger bat populations may thus lead to higher CoVs prevalence, as the number of roosts and/or roost size are likely to be higher. Hence, relationships between landscape composition and the presence of CoVs are expected to exist. To increase our understanding of the spread and shedding of coronaviruses in bat populations we studied the relationships between landscape composition and CoVs prevalence in the species Pipistrellus pipistrellus and Pipistrellus nathusii. Faecal samples were collected across The Netherlands, and were screened to detect the presence of CoV RNA. Coordinates were recorded for all faecal samples, so that landscape attributes could be quantified. Using a backward selection procedure on the basis of AIC, the landscape variables that best explained the presence of CoVs were selected in the final model. Results suggested that relationships between landscape composition and CoVs were likely associated with optimal foraging opportunities in both species, e.g. nearby water in P. nathusii or in areas with more grassland situated far away from forests for P. pipistrellus. Surprisingly, we found no positive association between built-up cover (where roosts are frequently found) and the presence of bat-CoVs for both species. We also show that samples collected from large bat roosts, such as maternity colonies, substantially increased the probability of finding CoVs in P. pipistrellus. Interestingly, while maternity colonies of P. nathusii are rarely present in The Netherlands, CoVs prevalence was similar in both species, suggesting that other mechanisms besides roost size, participate in the transmission of bat-CoVs. We encourage further studies to quantify bat roosts and colony networks over the different landscape compositions to better understand the ecological mechanisms involved in the transmission of bat-CoVs.

Gammaretroviruses, novel viruses and pathogenic bacteria in Australian bats with neurological signs, pneumonia and skin lesions

More than 70 bat species are found in mainland Australia. While most studies of bat viromes focus on sampling seemingly healthy individuals, little is known about the viruses and bacteria associated with diseased bats. We performed traditional diagnostic techniques and metatranscriptomic sequencing on tissue samples from 43 Australian bats, comprising three flying fox (Pteropodidae) and two microbat species experiencing a range of disease syndromes, including mass mortality, neurological signs, pneumonia and skin lesions. Of note, we identified the recently discovered Hervey pteropid gammaretrovirus in a bat with lymphoid leukemia, with evidence of replication consistent with an exogenous virus. The possible association of Hervey pteropid gammaretrovirus with lymphoid leukemia clearly merits additional investigation. One novel picornavirus and at least three new astroviruses and bat pegiviruses were also identified in a variety of tissue types, as well as a number of likely bacterial pathogens or opportunistic infections, most notably Pseudomonas aeruginosa.

Viral Co-Infection in Bats: A Systematic Review

Co-infection is an underappreciated phenomenon in contemporary disease ecology despite its ubiquity and importance in nature. Viruses, and other co-infecting agents, can interact in ways that shape host and agent communities, influence infection dynamics, and drive evolutionary selective pressures. Bats are host to many viruses of zoonotic potential and have drawn increasing attention in their role as wildlife reservoirs for human spillover. However, the role of co-infection in driving viral transmission dynamics within bats is unknown. Here, we systematically review peer-reviewed literature reporting viral co-infections in bats. We show that viral co-infection is common in bats but is often only reported as an incidental finding. Biases identified in our study database related to virus and host species were pre-existing in virus studies of bats generally. Studies largely speculated on the role co-infection plays in viral recombination and few investigated potential drivers or impacts of co-infection. Our results demonstrate that current knowledge of co-infection in bats is an ad hoc by-product of viral discovery efforts, and that future targeted co-infection studies will improve our understanding of the role it plays. Adding to the broader context of co-infection studies in other wildlife species, we anticipate our review will inform future co-infection study design and reporting in bats. Consideration of detection strategy, including potential viral targets, and appropriate analysis methodology will provide more robust results and facilitate further investigation of the role of viral co-infection in bat reservoirs.

Comparative virome analysis of individual shedding routes of Miniopterus phillipsi bats inhabiting the Wavul Galge cave, Sri Lanka

Bats are described as the natural reservoir host for a wide range of viruses. Although an increasing number of bat-associated, potentially human pathogenic viruses were discovered in the past, the full picture of the bat viromes is not explored yet. In this study, the virome composition of Miniopterus phillipsi bats (formerly known as Miniopterus fuliginosus bats in Sri Lanka) inhabiting the Wavul Galge cave, Sri Lanka, was analyzed. To assess different possible excretion routes, oral swabs, feces and urine were collected and analyzed individually by using metagenomic NGS. The data obtained was further evaluated by using phylogenetic reconstructions, whereby a special focus was set on RNA viruses that are typically associated with bats. Two different alphacoronavirus strains were detected in feces and urine samples. Furthermore, a paramyxovirus was detected in urine samples. Sequences related to Picornaviridae, Iflaviridae, unclassified Riboviria and Astroviridae were identified in feces samples and further sequences related to Astroviridae in urine samples. No viruses were detected in oral swab samples. The comparative virome analysis in this study revealed a diversity in the virome composition between the collected sample types which also represent different potential shedding routes for the detected viruses. At the same time, several novel viruses represent first reports of these pathogens from bats in Sri Lanka. The detection of two different coronaviruses in the samples indicates the potential general persistence of this virus species in M. phillipsi bats. Based on phylogenetics, the identified viruses are closely related to bat-associated viruses with comparably low estimation of human pathogenic potential. In further studies, the seasonal variation of the virome will be analyzed to identify possible shedding patterns for particular viruses.

Coronavirus sampling and surveillance in bats from 1996-2019: a systematic review and meta-analysis

The emergence of SARS-CoV-2 highlights a need for evidence-based strategies to monitor bat viruses. We performed a systematic review of coronavirus sampling (testing for RNA positivity) in bats globally. We identified 110 studies published between 2005 and 2020 that collectively reported positivity from 89,752 bat samples. We compiled 2,274 records of infection prevalence at the finest methodological, spatiotemporal and phylogenetic level of detail possible from public records into an open, static database named datacov, together with metadata on sampling and diagnostic methods. We found substantial heterogeneity in viral prevalence across studies, reflecting spatiotemporal variation in viral dynamics and methodological differences. Meta-analysis identified sample type and sampling design as the best predictors of prevalence, with virus detection maximized in rectal and faecal samples and by repeat sampling of the same site. Fewer than one in five studies collected and reported longitudinal data, and euthanasia did not improve virus detection. We show that bat sampling before the SARS-CoV-2 pandemic was concentrated in China, with research gaps in South Asia, the Americas and sub-Saharan Africa, and in subfamilies of phyllostomid bats. We propose that surveillance strategies should address these gaps to improve global health security and enable the origins of zoonotic coronaviruses to be identified.

Detection of coronaviruses in insectivorous bats of Fore-Caucasus, 2021

Coronaviruses (CoVs) pose a huge threat to public health as emerging viruses. Bat-borne CoVs are especially unpredictable in their evolution due to some unique features of bat physiology boosting the rate of mutations in CoVs, which is already high by itself compared to other viruses. Among bats, a meta-analysis of overall CoVs epizootiology identified a nucleic acid observed prevalence of 9.8% (95% CI 8.7-10.9%). The main objectives of our study were to conduct a qPCR screening of CoVs' prevalence in the insectivorous bat population of Fore-Caucasus and perform their characterization based on the metagenomic NGS of samples with detected CoV RNA. According to the qPCR screening, CoV RNA was detected in 5 samples, resulting in a 3.33% (95% CI 1.1-7.6%) prevalence of CoVs in bats from these studied locations. BetaCoVs reads were identified in raw metagenomic NGS data, however, detailed characterization was not possible due to relatively low RNA concentration in samples. Our results correspond to other studies, although a lower prevalence in qPCR studies was observed compared to other regions and countries. Further studies should require deeper metagenomic NGS investigation, as a supplementary method, which will allow detailed CoV characterization.

A study of viral pathogens in bat species in the Iberian Peninsula: identification of new coronavirus genetic variants

Bats have long been associated with multiple pathogens, including viruses affecting humans such as henipaviruses, filoviruses, bunyaviruses and coronaviruses. The alpha and beta coronaviruses genera can infect most mammalian species. Among them, betacoronavirus SARS-CoV, MERS-CoV and SARS-CoV-2, which have caused the three major pandemics in the last two decades, have been proposed to originate in bats. In this study, 194 oral swabs from 22 bats species sampled in 19 locations of the Iberian Peninsula were analysed and characterized by three different PCR tests (coronavirus generic real-time RT-PCR, multiplex conventional PCR, and SARS-CoV-2 specific real-time RT-PCR) to detect bat coronaviruses. Screening with coronavirus generic PCR showed 102 positives out of 194 oral swabs analysed. Then, metabarcoding with multiplex PCR amplified 15 positive samples. Most of the coronaviruses detected in this study belong to alphacoronavirus (α-CoV) genus, with multiple alphacoronaviruses identified by up to five different genetic variants coexisting in the same bat. One of the positive samples identified in a Miniopterus schreibersii bat positive for the generic coronavirus PCR and the specific SARS-CoV-2 PCR was classified as betacoronavirus (-CoV) through phylogenetic analysis. These results support the rapid evolution of coronaviruses to generate new genomic potentially pathogenic variants likely through co-infection and recombination.

The Genetic Characterization of the First Detected Bat Coronaviruses in Poland Revealed SARS-Related Types and Alphacoronaviruses

Bats are a major global reservoir of alphacoronaviruses (alphaCoVs) and betaCoVs. Attempts to discover the causative agents of COVID-19 and SARS have revealed horseshoe bats (Rhinolophidae) to be the most probable source of the virus. We report the first detection of bat coronaviruses (BtCoVs) in insectivorous bats in Poland and highlight SARS-related coronaviruses found in Rhinolophidae bats. The study included 503 (397 oral swabs and 106 fecal) samples collected from 20 bat species. Genetically diverse BtCoVs (n = 20) of the Alpha- and Betacoronavirus genera were found in fecal samples of two bat species. SARS-related CoVs were in 18 out of 58 lesser horseshoe bat (Rhinolophus hipposideros) samples (31%, 95% CI 20.6–43.8), and alphaCoVs were in 2 out of 55 Daubenton’s bat (Myotis daubentonii) samples (3.6%, 95% CI 0.6–12.3). The overall BtCoV prevalence was 4.0% (95% CI 2.6–6.1). High identity was determined for BtCoVs isolated from European M. daubentonii and R. hipposideros bats. The detection of SARS-related and alphaCoVs in Polish bats with high phylogenetic relatedness to reference BtCoVs isolated in different European countries but from the same species confirms their high host restriction. Our data elucidate the molecular epidemiology, prevalence, and geographic distribution of coronaviruses and particularly SARS-related types in the bat population.

High genetic diversity of alphacoronaviruses in bat species (Mammalia: Chiroptera) from the Atlantic Forest in Brazil

Bat coronaviruses (Bat-CoV) represent around 35% of all virus genomes described in bats. Brazil has one of the highest mammal species diversities, with 181 species of bats described so far. However, few Bat-CoV surveillance programs were carried out in the country. Thus, our aim was to evaluate the Bat-CoV diversity in the Atlantic Forest, the second biome with the highest number of bat species in Brazil. We analyzed 456 oral and rectal swabs and 22 tissue samples from Atlantic Forest bats, detecting Alphacoronavirus in 44 swab samples (9.64%) targeting the RdRp gene from seven different bat species, three of them that have never been described as Bat-CoV hosts. Phylogenetic analysis of the amino acid (aa) sequences coding the RdRp gene grouped the sequences obtained in our study with Bat-CoV previously detected in identical or congeneric bat species, with high aa identity (over 90%). The RdRp gene was also detected in three tissue samples from Diphylla ecaudata and Sturnira lilium, and the partial S gene was successfully sequenced in five tissues and swab samples of D. ecaudata. The phylogenetic analysis based on the partial S gene obtained here grouped with the sequence of D. ecaudata with CoV from Desmodus rotundus previously detected in Peru and Brazil, with aa identity ranging from 73.6% to 88.8%. Our data reinforce the wide distribution of Coronaviruses in bats from Brazil and the novelty of three bats species as Bat-CoV hosts and the co-circulation of four Alphacoronavirus subgenera in Brazil. This article is protected by copyright. All rights reserved.

Mixed-species groups in bats: non-random roost associations and roost selection in neotropical understory bats

BACKGROUND

Mixed-species groups in animals have been shown to confer antipredator, foraging and other benefits to their members that may provide selective advantages. In most cases, however, it is unclear whether functional benefits are a principal driver of heterospecific groups, or whether groups simply result from simultaneous exploitation of common resources. Mixed-species groups that form independently of environmental conditions may, however, evidence direct benefits of species associations. Bats are among the most gregarious mammals, with sometimes thousands of individuals of various species roosting communally. Despite numerous potential functional benefits of such mixed-species roosting groups, interspecific attraction has never been shown. To explore alternative explanations for mixed-species roosting, we studied roost selection in a speciose neotropical understory bat community in lowland rainforest in Costa Rica. Long term roost data were recorded over 10 years in a total of 133 roosts comprising both natural roosts and structurally uniform artificial roosts. We modelled bat roost occupancy and abundance in each roost type and in forest and pasture habitats to quantify the effects of roost- and environmental variability.

RESULTS

We found that bat species presence in natural roosts is predictable from habitat and structural roost parameters, but that the presence and abundance of other bat species further modifies roost choice. One third of the 12 study species were found to actively associate with selected other bat species in roosts (e.g. Glossophaga commissarisi with Carollia sowelli). Other species did not engage in communal roosting, which in some cases indicates a role for negative interspecific interactions, such as roost competition.

CONCLUSIONS

Mixed-species roosting may provide thermoregulatory benefits, reduce intraspecific competition and promote interspecific information transfer, and hence some heterospecific associations may be selected for in bats. Overall, our study contributes to an improved understanding of the array of factors that shape diverse tropical bat communities and drive the dynamics of heterospecific grouping in mammals more generally.

Characterization of bat coronaviruses: a latent global threat

It has been speculated that bats serve as reservoirs of a huge variety of emerging coronaviruses (CoVs) that have been responsible for severe havoc in human health systems as well as negatively affecting human economic and social systems. A prime example is the currently active severe acute respiratory syndrome (SARS)-CoV2, which presumably originated from bats, demonstrating that the risk of a new outbreak of bat coronavirus is always latent. Therefore, an in-depth investigation to better comprehend bat CoVs has become an important issue within the international community, a group that aims to attenuate the consequences of future outbreaks. In this review, we present a concise introduction to CoVs found in bats and discuss their distribution in Southeast Asia. We also discuss the unique adaptation features in bats that confer the ability to be a potential coronavirus reservoir. In addition, we review the bat coronavirus-linked diseases that have emerged in the last two decades. Finally, we propose key factors helpful in the prediction of a novel coronavirus outbreak and present the most recent methods used to forecast an evolving outbreak.

Update on Potentially Zoonotic Viruses of European Bats

Bats have been increasingly gaining attention as potential reservoir hosts of some of the most virulent viruses known. Numerous review articles summarize bats as potential reservoir hosts of human-pathogenic zoonotic viruses. For European bats, just one review article is available that we published in 2014. The present review provides an update on the earlier article and summarizes the most important viruses found in European bats and their possible implications for Public Health. We identify the research gaps and recommend monitoring of these viruses.

Full-Genome Sequences of Alphacoronaviruses and Astroviruses from Myotis and Pipistrelle Bats in Denmark

Bat species worldwide are receiving increased attention for the discovery of emerging viruses, cross-species transmission, and zoonoses, as well as for characterizing virus infections specific to bats. In a previous study, we investigated the presence of coronaviruses in faecal samples from bats at different locations in Denmark, and made phylogenies based on short, partial ORF1b sequences. In this study, selected samples containing bat coronaviruses from three different bat species were analysed, using a non-targeted approach of next-generation sequencing. From the resulting metagenomics data, we assembled full-genome sequences of seven distinct alphacoronaviruses, three astroviruses, and a polyomavirus, as well as partial genome sequences of rotavirus H and caliciviruses, from the different bat species. Comparisons to published sequences indicate that the bat alphacoronaviruses belong to three different subgenera-i.e., Pedacovirus, Nyctacovirus, and Myotacovirus-that the astroviruses may be new species in the genus Mamastrovirus, and that the polyomavirus could also be a new species, but unassigned to a genus. Furthermore, several viruses of invertebrates-including two Rhopalosiphum padi (aphid) viruses and a Kadipiro virus-present in the faecal material were assembled. Interestingly, this is the first detection in Europe of a Kadipiro virus.

Biodiversity loss and COVID-19 pandemic: The role of bats in the origin and the spreading of the disease

The loss of biodiversity in the ecosystems has created the general conditions that have favored and, in fact, made possible, the insurgence of the COVID-19 pandemic. A lot of factors have contributed to it: deforestation, changes in forest habitats, poorly regulated agricultural surfaces, mismanaged urban growth. They have altered the composition of wildlife communities, greatly increased the contacts of humans with wildlife, and altered niches that harbor pathogens, increasing their chances to come in contact with humans. Among the wildlife, bats have adapted easily to anthropized environments such as houses, barns, cultivated fields, orchards, where they found the suitable ecosystem to prosper. Bats are major hosts for αCoV and βCoV: evolution has shaped their peculiar physiology and their immune system in a way that makes them resistant to viral pathogens that would instead successfully attack other species, including humans. In time, the coronaviruses that bats host as reservoirs have undergone recombination and other modifications that have increased their ability for inter-species transmission: one modification of particular importance has been the development of the ability to use ACE2 as a receptor in host cells. This particular development in CoVs has been responsible for the serious outbreaks in the last two decades, and for the present COVID-19 pandemic.

First Detection of Bat Astroviruses (BtAstVs) among Bats in Poland: The Genetic BtAstVs Diversity Reveals Multiple Co-Infection of Bats with Different Strains

Background: Astroviruses (AstVs) are common pathogens of a wide range of animal hosts, including mammals and avians, causing gastrointestinal diseases, mainly gastroenteritis and diarrhea. They prompt a significant health problem in newborns and young children and economic losses in the poultry sector and mink farms. Recent studies revealed a growing number of bat species carrying astroviruses with a noticeable prevalence and diversity. Here, we demonstrate the first detection of bat astroviruses (BtAstVs) circulating in the population of insectivorous bats in the territory of Poland. Results: Genetically diverse BtAstVs (n = 18) were found with a varying degree of bat species specificity in five out of 15 bat species in Poland previously recognized as BtAstV hosts. Astroviral RNA was found in 12 out of 98 (12.2%, 95% CI 7.1–20.2) bat intestines, six bat kidneys (6.1%, 95% CI 2.8–12.7) and two bat livers (2.0%, 95% CI 0.4–7.1). Deep sequencing of the astroviral RNA-dependent RNA polymerase (RdRp) region revealed co-infections in five single bat individuals with highly distinct astrovirus strains. Conclusions: The detection of highly distinct bat astroviruses in Polish bats favors virus recombination and the generation of novel divergent AstVs and creates a potential risk of virus transmission to domestic animals and humans in the country. These findings provide a new insight into molecular epidemiology, prevalence of astroviruses in European bat populations and the risk of interspecies transmission to other animals including humans.

The heart microbiome of insectivorous bats from Central and South Eastern Europe

Host associated microbiome not only may affect the individual health-status or provide insights into the species- or group specific bacterial communities but may act as early warning signs in the assessment of zoonotic reservoirs, offering clues to predict, prevent and control possible episodes of emerging zoonoses. Bats may be carriers and reservoirs of multiple pathogens such as viruses, bacteria and parasites, showing in the same time robust immunity against many of them. The microbiota plays a fundamental role on the induction, training and function of the host immune system and the immune system has largely evolved in order to maintain the symbiotic relationship of the host with these diverse microbes. Thus, expanding our knowledge on bat-associated microbiome it can be usefully in understanding bats' outstanding immune capacities. The aim of this study was to investigate the presence of different bacterial communities in heart tissue of insectivorous bats, Nyctalus noctula, Pipistrellus pipistrellus and Rhinoplophus hipposideros, from Central and Eastern Europe using high-throughput sequencing of variable regions of the 16S rRNA. In addition, species-specific PCRs were used to validate the presence of the vector-borne pathogens Bartonella spp. and Rickettsia spp. In this study we identified a wide variety of bacterial groups, with the most abundant phyla being Proteobacteria and Firmicutes. The results showed that at individual level, the year or location had no effect on the diversity and composition of the microbiome, however host species determined both structure and abundance of the bacterial community. We report the presence of vector-borne bacteria Bartonella spp. in samples of N. noctula and indications of Rickettsia spp. in R. hipposideros. Our results provide a first insight into the bacterial community found in heart tissue of bats from Central and South Eastern Europe.

Extensive genetic diversity and host range of rodent-borne coronaviruses

To better understand the genetic diversity, host associations and evolution of coronaviruses (CoVs) in China we analyzed a total of 696 rodents encompassing 16 different species sampled from Zhejiang and Yunnan provinces. Based on reverse transcriptase PCR-based CoV screening of fecal samples and subsequent sequence analysis of the RNA-dependent RNA polymerase gene, we identified CoVs in diverse rodent species, comprising Apodemus agrarius, Apodemus chevrieri, Apodemus latronum, Bandicota indica, Eothenomys cachinus, Eothenomys miletus, Rattus andamanensis, Rattus norvegicus, and Rattus tanezumi. CoVs were particularly commonplace in A. chevrieri, with a detection rate of 12.44 per cent (24/193). Genetic and phylogenetic analysis revealed the presence of three groups of CoVs carried by a range of rodents that were closely related to the Lucheng Rn rat CoV (LRNV), China Rattus CoV HKU24 (ChRCoV_HKU24), and Longquan Rl rat CoV (LRLV) identified previously. One newly identified A. chevrieri-associated virus closely related to LRNV lacked an NS2 gene. This virus had a similar genetic organization to AcCoV-JC34, recently discovered in the same rodent species in Yunnan, suggesting that it represents a new viral subtype. Notably, additional variants of LRNV were identified that contained putative non-structural (NS)2b genes located downstream of the NS2 gene that were likely derived from the host genome. Recombination events were also identified in the open reading frame (ORF) 1a gene of Lijiang-71. In sum, these data reveal the substantial genetic diversity and genomic complexity of rodent-borne CoVs, and extend our knowledge of these major wildlife virus reservoirs.

Analysis of astrovirus transmission pathways in a free-ranging fission-fusion colony of Natterer’s bats (Myotis nattereri)

Abstract

Bats are a diverse and widespread order of mammals. They fulfill critical ecosystem roles but may also act as reservoirs and spreaders for zoonotic agents. Consequently, many recent studies have focused on the potential of bats to spread diseases to other animals and to humans. However, virus transmission networks within bat colonies remain largely unexplored. We studied the detection rate and transmission pathway of astroviruses in a free-ranging Natterer’s bat colony (Myotis nattereri) that exhibits a high fission-fusion dynamic. Based on automatic roost monitoring data of radio-frequency identification tagged bats, we assessed the impact of the strength of an individual’s roosting associations with all other colony members (weighted degree), and the number of roost sites (bat boxes) an individual used—both being proxies for individual exposure risk—on the detected presence of astrovirus-related nucleic acid in individual swab samples. Moreover, we tested to which degree astrovirus sequence types were shared between individuals that frequently roosted together, as proxy for direct transmission risk, and between bats sharing the same roost sites in close temporal succession, as proxy for indirect transmission risk. Neither roosting associations nor the number of different roost sites had an effect on detected virus presence in individual bats. Transmission network data suggest that astroviruses are transmitted both via direct and indirect contact, implying that roost sites pose a risk of astrovirus infection for several days after the bats leave them. Our study offers novel insights in the presence and transmission of viruses within social networks of bat colonies.

Significance statement

Bats provide many ecosystem services but have moved into the focus of virological research as potential carriers of zoonotic disease agents. However, the sparse information available about virus transmission within bat colonies is solely based on simulated transmission data. In this field study, we examined the daily roosting behavior in a wild bat colony in relation to the presence of viruses in individual colony members. Our findings suggest that astroviruses are transmitted by direct contact and via contaminated roost sites. Bats typically defecate in their roost sites, and astroviruses can remain infectious in feces for several days. The here observed virus diversity and roosting behavior suggest that bats can contract astroviruses even if they use contaminated roost sites days after infected individuals have left. This study provides first-time insights in the transmission of astroviruses within bat colonies in the wild.

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.

Global Epidemiology of Bat Coronaviruses

Bats are a unique group of mammals of the order Chiroptera. They are highly diversified and are the group of mammals with the second largest number of species. Such highly diversified cell types and receptors facilitate them to be potential hosts of a large variety of viruses. Bats are the only group of mammals capable of sustained flight, which enables them to disseminate the viruses they harbor and enhance the chance of interspecies transmission. This article aims at reviewing the various aspects of the global epidemiology of bat coronaviruses (CoVs). Before the SARS epidemic, bats were not known to be hosts for CoVs. In the last 15 years, bats have been found to be hosts of >30 CoVs with complete genomes sequenced, and many more if those without genome sequences are included. Among the four CoV genera, only alphaCoVs and betaCoVs have been found in bats. As a whole, both alphaCoVs and betaCoVs have been detected from bats in Asia, Europe, Africa, North and South America and Australasia; but alphaCoVs seem to be more widespread than betaCoVs, and their detection rate is also higher. For betaCoVs, only those from subgenera Sarbecovirus, Merbecovirus, Nobecovirus and Hibecovirus have been detected in bats. Most notably, horseshoe bats are the reservoir of SARS-CoV, and several betaCoVs from subgenus Merbecovirus are closely related to MERS-CoV. In addition to the interactions among various bat species themselves, bat⁻animal and bat⁻human interactions, such as the presence of live bats in wildlife wet markets and restaurants in Southern China, are important for interspecies transmission of CoVs and may lead to devastating global outbreaks.

Bats and Viruses: Emergence of Novel Lyssaviruses and Association of Bats with Viral Zoonoses in the EU

Bats in the EU have been associated with several zoonotic viral pathogens of significance to both human and animal health. Virus discovery continues to expand the existing understating of virus classification, and the increased interest in bats globally as reservoirs or carriers of zoonotic agents has fuelled the continued detection and characterisation of new lyssaviruses and other viral zoonoses. Although the transmission of lyssaviruses from bat species to humans or terrestrial species appears rare, interest in these viruses remains, through their ability to cause the invariably fatal encephalitis—rabies. The association of bats with other viral zoonoses is also of great interest. Much of the EU is free of terrestrial rabies, but several bat species harbor lyssaviruses that remain a risk to human and animal health. Whilst the rabies virus is the main cause of rabies globally, novel related viruses continue to be discovered, predominantly in bat populations, that are of interest purely through their classification within the lyssavirus genus alongside the rabies virus. Although the rabies virus is principally transmitted from the bite of infected dogs, these related lyssaviruses are primarily transmitted to humans and terrestrial carnivores by bats. Even though reports of zoonotic viruses from bats within the EU are rare, to protect human and animal health, it is important characterise novel bat viruses for several reasons, namely: (i) to investigate the mechanisms for the maintenance, potential routes of transmission, and resulting clinical signs, if any, in their natural hosts; (ii) to investigate the ability of existing vaccines, where available, to protect against these viruses; (iii) to evaluate the potential for spill over and onward transmission of viral pathogens in novel terrestrial hosts. This review is an update on the current situation regarding zoonotic virus discovery within bats in the EU, and provides details of potential future mechanisms to control the threat from these deadly pathogens.

Full genome characterization of two novel Alpha-coronavirus species from Italian bats

Coronaviruses (CoVs) have been detected worldwide in several bat species, which are considered the main reservoir. The attention to the high diversity of CoVs hosted by bats has increased during the last decade due to the high number of human infections caused by two zoonotic Beta-CoVs, SARS-CoV and MERS-CoV, that cause several respiratory diseases. Among coronaviruses, two Alpha-CoV strains (HuCoV-229E and HuCoV-NL63) cause mild respiratory disease that can change to severe disease in children, elderly and individuals affected by illnesses. Phylogenetic analysis conducted on bat Alpha-CoV strains revealed their evolutive correlation to human strains, suggesting their origin in bats. The genome of CoVs is characterized by a high frequency of mutations and recombination events, increasing their ability to switch hosts and their zoonotic potential. In this study, three strains of Alpha-CoV genera detected in Italian bats (Pipistrellus kuhlii) were fully sequenced by Next Generation Sequencing (NGS) and characterized. The complete genome analysis showed the correlation of the Italians strains with a Chinese strain detected in 2013 and, based on CoV molecular species demarcation, two new Alpha-CoV species were established. The analysis of a fragment of the RNA-dependent RNA polymerase (RdRp) showed the correlation of the Italian strains with CoVs that was only detected in the bat Pipistrellus genera (Pipistrellus kuhlii and Pipistrellus Pipistrellus) in European countries.

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

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

SARS-CoV related Betacoronavirus and diverse Alphacoronavirus members found in western old-world

The emergence of SARS-CoV and MERS-CoV, triggered the discovery of a high diversity of coronaviruses in bats. Studies from Europe have shown that coronaviruses circulate in bats in France but this reflects only a fraction of the whole diversity. In the current study the diversity of coronaviruses circulating in western Europe was extensively explored. Ten alphacoronaviruses in eleven bat species belonging to the Miniopteridae, Vespertilionidae and Rhinolophidae families and, a SARS-CoV-related Betacoronavirus in Rhinolophus ferrumequinum were identified. The diversity and prevalence of bat coronaviruses presently reported from western Europe is much higher than previously described and includes a SARS-CoV sister group. This diversity demonstrates the dynamic evolution and circulation of coronaviruses in this species. That said, the identified coronaviruses were consistently associated with a particular bat species or genus, and these relationships were maintained no matter the geographic location. The observed phylogenetic grouping of coronaviruses from the same species in Europe and Asia, emphasizes the role of host/pathogen coevolution in this group.

Coronavirus and paramyxovirus in bats from Northwest Italy

Background

Bat-borne virus surveillance is necessary for determining inter-species transmission risks and is important due to the wide-range of bat species which may harbour potential pathogens. This study aimed to monitor coronaviruses (CoVs) and paramyxoviruses (PMVs) in bats roosting in northwest Italian regions. Our investigation was focused on CoVs and PMVs due to their proven ability to switch host and their zoonotic potential. Here we provide the phylogenetic characterization of the highly conserved polymerase gene fragments.

Results

Family-wide PCR screenings were used to test 302 bats belonging to 19 different bat species. Thirty-eight animals from 12 locations were confirmed as PCR positive, with an overall detection rate of 12.6% [95% CI: 9.3–16.8]. CoV RNA was found in 36 bats belonging to eight species, while PMV RNA in three Pipistrellus spp. Phylogenetic characterization have been obtained for 15 alpha- CoVs, 5 beta-CoVs and three PMVs; moreover one P. pipistrellus resulted co-infected with both CoV and PMV. A divergent alpha-CoV clade from Myotis nattereri SpA is also described. The compact cluster of beta-CoVs from R. ferrumequinum roosts expands the current viral sequence database, specifically for this species in Europe. To our knowledge this is the first report of CoVs in Plecotus auritus and M. oxygnathus, and of PMVs in P. kuhlii.

Conclusions

This study identified alpha and beta-CoVs in new bat species and in previously unsurveyed Italian regions. To our knowledge this represents the first and unique report of PMVs in Italy. The 23 new bat genetic sequences presented will expand the current molecular bat-borne virus databases. Considering the amount of novel bat-borne PMVs associated with the emergence of zoonotic infections in animals and humans in the last years, the definition of viral diversity within European bat species is needed. Performing surveillance studies within a specific geographic area can provide awareness of viral burden where bats roost in close proximity to spillover hosts, and form the basis for the appropriate control measures against potential threats for public health and optimal management of bats and their habitats.

Identification of Alpha and Beta Coronavirus in Wildlife Species in France: Bats, Rodents, Rabbits, and Hedgehogs

Coronaviruses are closely monitored in the context of emerging diseases and, as illustrated with Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and Middle East Respiratory Syndrome-coronavirus (MERS-CoV), are known to cross the species barrier and eventually to move from wildlife to humans. Knowledge of the diversity of coronaviruses in wildlife is therefore essential to better understand and prevent emergence events. This study explored the presence of coronaviruses in four wild mammal orders in France: Bats, rodents, lagomorphs, and hedgehogs. Betacoronavirus and Alphacoronavirus genera were identified. The results obtained suggest the circulation of potentially evolving virus strains, with the potential to cross the species barrier.

Influence of age and body condition on astrovirus infection of bats in Singapore: An evolutionary and epidemiological analysis

Bats are unique mammals that are reservoirs of high levels of virus diversity. Although several of these viruses are zoonotic, the majority are not. Astroviruses, transmitted fecal-orally, are commonly detected in a wide diversity of bat species, are prevalent at high rates and are not thought to directly infect humans. These features make astroviruses useful in examining virus evolutionary history, epidemiology in the host, and temporal shedding trends. Our study screened for the presence of astroviruses in bats in Singapore, reconstructed the phylogenetic relations of the polymerase genes and tested for population characteristics associated with infection. Of the seven species screened, astroviruses were detected in Rhinolophus lepidus and Eonycteris spelaea. The R. lepidus sequences grouped with other Rhinolophus astrovirus sequences from China and Laos, while the Eoncyteris sequences formed a distinct clade with astroviruses from Rousettus spp. in Laos and Pteropus giganteus in Bangladesh, but not with other E. spelaea sequences. Longitudinal collections of Eonycteris feces demonstrated variable shedding. Juvenile status of bats was a risk factor for astroviruses. This study highlights the diversity of astroviruses in nectivorous and insectivorous bats in Singapore and provides a predictive framework for understanding astrovirus infection in these bats. It also suggests that in addition to host phylogenetic relatedness, host ecology, such as roosting behavior, may drive co-infections, virus maintenance and spillover.

Novel Alphacoronaviruses and Paramyxoviruses Cocirculate with Type 1 and Severe Acute Respiratory System (SARS)-Related Betacoronaviruses in Synanthropic Bats of Luxembourg

Several infectious disease outbreaks with high mortality in humans have been attributed to viruses that are thought to have evolved from bat viruses. In this study from Luxembourg, the genetic diversity and epidemiology of paramyxoviruses and coronaviruses shed by the bat species Rhinolophus ferrumequinum and Myotis emarginatus were evaluated. Feces collection (n = 624) was performed longitudinally in a mixed-species colony in 2015 and 2016. In addition, feces (n = 254) were collected cross-sectionally from six Myotis emarginatus colonies in 2016. By use of degenerate primers in a nested format, overall prevalences of 1.1% (10/878) and 4.9% (43/878) were determined for paramyxoviruses and coronaviruses. Sequences of the partial RNA-dependent RNA polymerase and spike glycoprotein genes of coronaviruses, as well as sequences of the partial L gene of paramyxoviruses, were obtained. Novel paramyxovirus and Alphacoronavirus strains were identified in different Myotis emarginatus colonies, and severe acute respiratory syndrome (SARS)-related Betacoronavirus strains were shed by Rhinolophus ferrumequinum Logistic regression revealed that the level of Alphacoronavirus shedding was highest in July (odds ratio, 2.8; P < 0.01), probably due to periparturient stress. Phylogenetic analyses point to close virus-host coevolution, and the high genetic similarity of the study strains suggests that the Myotis emarginatus colonies in Luxembourg are socially connected. Most interestingly, we show that bats also host Betacoronavirus1 strains. The high similarity of the spike gene sequences of these viruses with mammalian Betacoronavirus 1 strains may be of concern. Both the SARS-related and Betacoronavirus 1 strains detected in bats in Luxembourg may cross the species barrier after a host adaptation process.IMPORTANCE Bats are a natural reservoir of a number of zoonotic pathogens. Several severe outbreaks in humans (e.g., a Nipah virus outbreak in Malaysia in 1998, and the almost global spread of severe acute respiratory syndrome in 2003) have been caused by bat-borne viruses that were transmitted to humans mostly after virus adaptation (e.g., in intermediate animal hosts). Despite the indigenousness of bat species that host viruses with suspected zoonotic potential and despite the zoonotic transmission of European bat 1 lyssavirus in Luxembourg, knowledge about the diversity and epidemiology of bat viruses remains limited in this country. Moreover, in contrast to other European countries, bat viruses are currently not included in the national surveillance activities of this land-locked country. We suggest that this gap in disease surveillance should be addressed, since we show here that synanthropic bats host viruses that may be able to cross the species barrier.

Seasonal Fluctuations of Astrovirus, But Not Coronavirus Shedding in Bats Inhabiting Human-Modified Tropical Forests

Emerging infectious diseases (EIDs) are considered a major threat to global health. Most EIDs appear to result from increased contact between wildlife and humans, especially when humans encroach into formerly pristine habitats. Habitat deterioration may also negatively affect the physiology and health of wildlife species, which may eventually lead to a higher susceptibility to infectious agents and/or increased shedding of the pathogens causing EIDs. Bats are known to host viruses closely related to important EIDs. Here, we tested in a paleotropical forest with ongoing logging and fragmentation, whether habitat disturbance influences the occurrence of astro- and coronaviruses in eight bat species. In contrast to our hypothesis, anthropogenic habitat disturbance was not associated with corona- and astrovirus detection rates in fecal samples. However, we found that bats infected with either astro- or coronaviruses were likely to be coinfected with the respective other virus. Additionally, we identified two more risk factors influencing astrovirus shedding. First, the detection rate of astroviruses was higher at the beginning of the rainy compared to the dry season. Second, there was a trend that individuals with a poor body condition had a higher probability of shedding astroviruses in their feces. The identification of risk factors for increased viral shedding that may potentially result in increased interspecies transmission is important to prevent viral spillovers from bats to other animals, including humans.

Novel coronaviruses, astroviruses, adenoviruses and circoviruses in insectivorous bats from northern China

Bats are considered as the reservoirs of several emerging infectious disease, and novel viruses are continually found in bats all around the world. Studies conducted in southern China found that bats carried a variety of viruses. However, few studies have been conducted on bats in northern China, which harbours a diversity of endemic insectivorous bats. It is important to understand the prevalence and diversity of viruses circulating in bats in northern China. In this study, a total of 145 insectivorous bats representing six species were collected from northern China and screened with degenerate primers for viruses belonging to six families, including coronaviruses, astroviruses, hantaviruses, paramyxoviruses, adenoviruses and circoviruses. Our study found that four of the viruses screened for were positive and the overall detection rates for astroviruses, coronaviruses, adenoviruses and circoviruses in bats were 21.4%, 15.9%, 20% and 37.2%, respectively. In addition, we found that bats in northern China harboured a diversity of novel viruses. Common Serotine (Eptesicus serotinu), Fringed long‐footed Myotis (Myotis fimriatus) and Peking Myotis (Myotis pequinius) were investigated in China for the first time. Our study provided new information on the ecology and phylogeny of bat‐borne viruses.

Bat Astroviruses: Towards Understanding the Transmission Dynamics of a Neglected Virus Family

Bats belong to the order Chiroptera that represents the second largest order of mammals with more than 1200 species and an almost global distribution. Environmental changes and deforestation have severely influenced many ecosystems, intensifying the contact between wildlife and humans. In recent years, bats have been found to harbor a number of different viruses with zoonotic potential, as well as a great diversity of astroviruses, for which the question of zoonotic potential remains unanswered to date. Human astroviruses have been identified as the causative agent for diarrhea in children and immunocompromised patients. For a long time, astroviruses have been considered to be strictly species-specific. However, a great genetic diversity has recently been discovered among animal and human astroviruses that might indicate the potential of these viruses to cross species barriers. Furthermore, our knowledge about the tissue tropism of astroviruses has been expanded to some neurotropic strains that have recently been shown to be responsible for encephalitis in humans and livestock. This review gives an overview on what is known about astroviruses in bats, humans and livestock, especially bovines and pigs. Future research activities are suggested to unravel astrovirus infection dynamics in bat populations to further assess the zoonotic potential of these viruses.

Evidence for genetic variation in Natterer's bats (Myotis nattereri) across three regions in Germany but no evidence for co-variation with their associated astroviruses

Background

As bats have recently been described to harbor many different viruses, several studies have investigated the genetic co-variation between viruses and different bat species. However, little is known about the genetic co-variation of viruses and different populations of the same bat species, although such information is needed for an understanding of virus transmission dynamics within a given host species. We hypothesized that if virus transmission between host populations depends on events linked to gene flow in the bats, genetic co-variation should exist between host populations and astroviruses.

Results

We used 19 nuclear and one mitochondrial microsatellite loci to analyze the genetic population structure of the Natterer’s bat (Myotis nattereri) within and among populations at different geographical scales in Germany. Further, we correlated the observed bat population structure to that of partial astrovirus sequences (323–394 nt fragments of the RNA-dependent RNA polymerase gene) obtained from the same bat populations. Our analyses revealed that the studied bat colonies can be grouped into three distinct genetic clusters, corresponding to the three geographic regions sampled. Furthermore, we observed an overall isolation-by-distance pattern, while no significant pattern was observed within a geographic region. Moreover, we found no correlation between the genetic distances among the bat populations and the astrovirus sequences they harbored. Even though high genetic similarity of some of the astrovirus haplotypes found in several different regions was detected, identical astrovirus haplotypes were not shared between different sampled regions.

Conclusions

The genetic population structure of the bat host suggests that mating sites where several local breeding colonies meet act as stepping-stones for gene flow. Identical astrovirus haplotypes were not shared between different sampled regions suggesting that astroviruses are mostly transmitted among host colonies at the local scale. Nevertheless, high genetic similarity of some of the astrovirus haplotypes found in several different regions implies that occasional transmission across regions with subsequent mutations of the virus haplotypes does occur.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-016-0856-0) contains supplementary material, which is available to authorized users.

Genetic diversity of coronaviruses in bats in Lao PDR and Cambodia

South-East Asia is a hot spot for emerging zoonotic diseases, and bats have been recognized as hosts for a large number of zoonotic viruses such as Severe Acute Respiratory Syndrome (SARS), responsible for acute respiratory syndrome outbreaks. Thus, it is important to expand our knowledge of the presence of viruses in bats which could represent a risk to humans. Coronaviruses (CoVs) have been reported in bat species from Thailand, China, Indonesia, Taiwan and the Philippines. However no such work was conducted in Cambodia or Lao PDR. Between 2010 and 2013, 1965 bats were therefore sampled at interfaces with human populations in these two countries. They were tested for the presence of coronavirus by consensus reverse transcription-PCR assay. A total of 93 samples (4.7%) from 17 genera of bats tested positive. Sequence analysis revealed the presence of potentially 37 and 56 coronavirus belonging to alpha-coronavirus (αCoV) and beta-CoV (βCoV), respectively. The βCoVs group is known to include some coronaviruses highly pathogenic to human, such as SARS-CoV and MERS-CoV. All coronavirus sequences generated from frugivorous bats (family Pteropodidae) (n = 55) clustered with other bat βCoVs of lineage D, whereas one coronavirus from Pipistrellus coromandra fell in the lineage C of βCoVs which also includes the MERS-CoV. αCoVs were all detected in various genera of insectivorous bats and clustered with diverse bat αCoV sequences previously published. A closely related strain of PEDV, responsible for severe diarrhea in pigs (PEDV-CoV), was detected in 2 Myotis bats. We highlighted the presence and the high diversity of coronaviruses circulating in bats from Cambodia and Lao PDR. Three new bat genera and species were newly identified as host of coronaviruses, namely Macroglossus sp., Megaerops niphanae and Myotis horsfieldii

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Coronaviruses detected in bats from Lao PDR and Cambodia.

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High diversity of αCoVs and βCoVs circulating in bats in Cambodia and Lao PDR.

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One strain of βCoV, a new member of the MERS-CoV sister-clade, detected from Pipistrellus coromandra.

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A αCoV strain genetically related to PEDV-CoV, detected from Myotis horsfieldii.

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CoVs detected for the first time in Megaerops niphanae, Myotis horsfieldii and Macroglossus sp.

Diversity of bat astroviruses in Lao PDR and Cambodia

Astroviruses are known to infect humans and a wide range of animal species, and can cause gastroenteritis in their hosts. Recent studies have reported astroviruses in bats in Europe and in several locations in China. We sampled 1876 bats from 17 genera at 45 sites from 14 and 13 provinces in Cambodia and Lao PDR respectively, and tested them for astroviruses. Our study revealed a high diversity of astroviruses among various Yangochiroptera and Yinpterochiroptera bats. Evidence for varying degrees of host restriction for astroviruses in bats was found. Furthermore, additional Pteropodid hosts were detected. The astroviruses formed distinct phylogenetic clusters within the genus Mamastrovirus, most closely related to other known bat astroviruses. The astrovirus sequences were found to be highly saturated indicating that phylogenetic relationships should be interpreted carefully. An astrovirus clustering in a group with other viruses from diverse hosts, including from ungulates and porcupines, was found in a Rousettus bat. These findings suggest that diverse astroviruses can be found in many species of mammals, including bats.

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Diverse astroviruses detected in bats in Lao PDR and Cambodia

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High polymorphism of astroviruses found in insectivorous and frugivorous bats

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High level of genome saturation and hypermutation potential evidenced in astrovirus

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Detection of additional astrovirus bat hosts, i.e. nectar bats from the genus Eonycteris

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Discovery of a new species of astrovirus in fruit bats (Rousettus sp.)

Bats as Viral Reservoirs

Bats are hosts of a range of viruses, including ebolaviruses, and many important human viral infections, such as measles and mumps, may have their ancestry traced back to bats. Here, I review viruses of all viral families detected in global bat populations. The viral diversity in bats is substantial, and viruses with all known types of genomic structures and replication strategies have been discovered in bats. However, the discovery of viruses is not geographically even, with some apparently undersampled regions, such as South America. Furthermore, some bat families, including those with global or wide distributions such as Emballonuridae and Miniopteridae, are underrepresented on viral databases. Future studies, including those that address these sampling gaps along with those that develop our understanding of viral-host relationships, are highlighted.

Alphacoronavirus in urban Molossidae and Phyllostomidae bats, Brazil

Background

Bats have been implicated as the main reservoir of coronavirus (CoV). Thus the role of these hosts on the evolution and spread of CoVs currently deserve the attention of emerging diseases surveillance programs. On the view of the interest on and importance of CoVs in bats the occurrence and molecular characterization of CoV were conducted in bats from Brazil.

Findings

Three hundred five enteric contents of 29 bat species were tested using a panCoV nested RT-PCR. Nine specimens were positive and eight was suitable for RdRp gene sequencing. RdRp gene phylogeny showed that all CoVs strains from this study cluster in Alphacoronavirus genus, with one Molossidae and one Phlyllostomidae-CoV specific groups. Phylogenetic analyses of two S gene sequences showed a large diversity within the Alphacoronavirus genus.

Conclusions

This study indicated a CoV-to-host specificity and draws attention for CoV detection in Cynomops sp, a potential new reservoir. The phylogenetic analyses indicate that diversity of CoV in bats is higher than previously known.