Novel papillomaviruses in free-ranging Iberian bats: no virus-host co-evolution, no strict host specificity, and hints for recombination

Full-genome sequencing of dozens of new DNA viruses found in Spanish bat feces

Bats are natural hosts of multiple viruses, many of which have clear zoonotic potential. The search for emerging viruses has been aided by the implementation of metagenomic tools, which have also enabled the detection of unprecedented viral diversity. Currently, this search is mainly focused on RNA viruses, which are largely over-represented in databases. To compensate for this research bias, we analyzed fecal samples from 189 Spanish bats belonging to 22 different species using viral metagenomics. This allowed us to identify 52 complete or near-complete viral genomes belonging to the families Adenoviridae, Circoviridae, Genomoviridae, Papillomaviridae, Parvoviridae, Polyomaviridae and Smacoviridae. Of these, 30 could constitute new species, doubling the number of viruses currently described in Europe. These findings open the door to a more thorough analysis of bat DNA viruses and their zoonotic potential.

IMPORTANCE

Metagenomics has become a fundamental tool to characterize the global virosphere, allowing us not only to understand the existing viral diversity and its ecological implications but also to identify new and emerging viruses. RNA viruses have a higher zoonotic potential, but this risk is also present for some DNA virus families. In our study, we analyzed the DNA fraction of fecal samples from 22 Spanish bat species, identifying 52 complete or near-complete genomes of different viral families with zoonotic potential. This doubles the number of genomes currently described in Europe. Metagenomic data often produce partial genomes that can be difficult to analyze. Our work, however, has characterized a large number of complete genomes, thus facilitating their taxonomic classification and enabling different analyses to be carried out to evaluate their zoonotic potential. For example, recombination studies are relevant since this phenomenon could play a major role in cross-species transmission.

Epidemiological characterization of oral focal epithelial hyperplasia in brown howler monkeys (Alouatta guariba clamitans)

BACKGROUND

Oral focal epithelial hyperplasia (FEH) is an uncommon infection affecting humans, chimpanzees, bonobos, and howler monkeys. This study describes 10 cases of free-ranging brown howler monkeys (Alouatta guariba clamitans) diagnosed with FEH and Alouatta guariba Papillomavirus 1 (AgPV 1).

METHODS

We analyzed demographic characteristics, rescue conditions, clinical and pathological findings, and species-specific behavior factors in these cases. The study assessed the frequency of occurrence and potential contributing factors of FEH and AgPV 1 infection.

RESULTS

The frequency of FEH was 8.13%. Most affected howlers were adult or geriatric males with comorbidities or stressful conditions. Clinical and pathological observations were consistent with AgPV 1 infection. Species-specific behaviors and environmental stressors were identified as contributing factors.

CONCLUSIONS

FEH associated with AgPV 1 affected mainly adult or geriatric males with ongoing comorbidities or stressful conditions. Further research is needed to understand these factors for effective management.

Virome analysis of New Zealand's bats reveals cross-species viral transmission among the Coronaviridae

The lesser short-tailed bat (Mystacina tuberculata) and the long-tailed bat (Chalinolobus tuberculatus) are Aotearoa New Zealand's only native extant terrestrial mammals and are believed to have migrated from Australia. Long-tailed bats arrived in New Zealand an estimated two million years ago and are closely related to other Australian bat species. Lesser short-tailed bats, in contrast, are the only extant species within the Mystacinidae and are estimated to have been living in isolation in New Zealand for the past 16-18 million years. Throughout this period of isolation, lesser short-tailed bats have become one of the most terrestrial bats in the world. Through a metatranscriptomic analysis of guano samples from eight locations across New Zealand, we aimed to characterise the viromes of New Zealand's bats and determine whether viruses have jumped between these species over the past two million years. High viral richness was observed among long-tailed bats with viruses spanning seven different viral families. In contrast, no bat-specific viruses were identified in lesser short-tailed bats. Both bat species harboured an abundance of likely dietary- and environment-associated viruses. We also identified alphacoronaviruses in long-tailed bat guano that had previously been identified in lesser short-tailed bats, suggesting that these viruses had jumped the species barrier after long-tailed bats migrated to New Zealand. Of note, an alphacoronavirus species discovered here possessed a complete genome of only 22,416 nucleotides with entire deletions or truncations of several non-structural proteins, thereby representing what may be the shortest genome within the Coronaviridae identified to date. Overall, this study has revealed a diverse range of novel viruses harboured by New Zealand's only native terrestrial mammals, in turn expanding our understanding of bat viral dynamics and evolution globally.

Interspecies Papillomavirus Type Infection and a Novel Papillomavirus Type in Red Ruffed Lemurs (Varecia rubra)

The Papillomaviridae are a family of vertebrate-infecting viruses of oncogenic potential generally thought to be host species- and tissue-specific. Despite their phylogenetic relatedness to humans, there is a scarcity of data on papillomaviruses (PVs) in speciose non-human primate lineages, particularly the lemuriform primates. Varecia variegata (black-and-white ruffed lemurs) and Varecia rubra (red ruffed lemurs), two closely related species comprising the Varecia genus, are critically endangered with large global captive populations. Varecia variegata papillomavirus (VavPV) types -1 and -2, the first PVs in lemurs with a fully identified genome, were previously characterized from captive V. variegata saliva. To build upon this discovery, saliva samples were collected from captive V. rubra with the following aims: (1) to identify PVs shared between V. variegata and V. rubra and (2) to characterize novel PVs in V. rubra to better understand PV diversity in the lemuriform primates. Three complete PV genomes were determined from V. rubra samples. Two of these PV genomes share 98% L1 nucleotide identity with VavPV2, denoting interspecies infection of V. rubra by VavPV2. This work represents the first reported case of interspecies PV infection amongst the strepsirrhine primates. The third PV genome shares <68% L1 nucleotide identity with that of all PVs. Thus, it represents a new PV species and has been named Varecia rubra papillomavirus 1 (VarPV1). VavPV1, VavPV2, and VarPV1 form a new clade within the Papillomaviridae family, likely representing a novel genus. Future work diversifying sample collection (i.e., lemur host species from multiple genera, sample type, geographic location, and wild populations) is likely to uncover a world of diverse lemur PVs.

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.

Complete genomic characterization of bovine papillomavirus type 1 and 2 strains infers ongoing cross-species transmission between cattle and horses

Infection with bovine papillomavirus (BPV) types 1 and 2 results in the most common skin tumor of horses, termed equine sarcoid. The persistent and recurrent nature of this tumor stands in contrast to the regressive nature of BPV-1/- 2 induced cutaneous papillomas in cattle. The circulation of horse-specific BPV-1/- 2 variants within equine populations has been suggested as a possible explanation for the difference in clinical presentation of BPV-1/- 2 infection between horses and cattle. In order to investigate this hypothesis, we identified 98 complete BPV-1/- 2 genomes using a Nanopore sequencing approach. Separate BPV-1/- 2 alignments were used to infer Bayesian phylogenetic trees. Phylogeny-trait association concerning host species was investigated using Bayesian Tip-association Significance software (BaTS) Overall, 179 unique BPV-1 and 128 BPV-2 substitutions were found. The E2 coding region in the viral genome exhibited an exceptionally high rate of non-synonymous mutations (81 %, n = 13/16). Interestingly, extensive deletions in the L1/L2 region (up to 1.5 kb) were found exclusively in horse-derived samples. Nevertheless, the most frequently detected single nucleotide polymorphisms were shared between equine and bovine hosts, which is in agreement with BaTS results indicating no phylogeny-host correlation. We found indications that horse-specific mutations might exist in subpopulations of equine derived BPV-1/- 2, but these did not result in horse-adapted genetic variants. Based on these observations, cross-species transmission from cattle to horses seems to be an ongoing process, rather than an ancient occurrence that has been followed by the circulation of horse-adapted BPV variants in the horse population..

Identification and evolutionary analysis of papillomavirus sequences in New World monkeys (genera Sapajus and Alouatta) from Argentina

OBJECTIVE

In this study, we investigated the occurrence of papillomavirus (PV) infection in non-human primates (NHPs) in northeastern Argentina. We also explored their evolutionary history and evaluated the co-speciation hypothesis in the context of primate evolution.

METHODS

We obtained DNA samples from 57 individuals belonging to wild and captive populations of Alouatta caraya, Sapajus nigritus, and Sapajus cay. We assessed PV infection by PCR amplification with the CUT primer system and sequencing of 337 bp (112 amino acids) of the L1 gene. The viral sequences were analyzed by phylogenetic and Bayesian coalescence methods to estimate the time to the most common recent ancestor (t_MRCA) using BEAST, v1.4.8 software. We evaluated viral/host tree congruence with TreeMap v3.0.

RESULTS

We identified two novel putative PV sequences of the genus Gammapapillomavirus in Sapajus spp. and Alouatta caraya (SPV1 and AcPV1, respectively). The t_MRCA of SPV1 was estimated to be 11,941,682 years before present (ybp), and that of AcPV1 was 46,638,071 ybp, both before the coalescence times of their hosts (6.4 million years ago [MYA] and 6.8 MYA, respectively). Based on the comparison of primate and viral phylogenies, we found that the PV tree was no more congruent with the host tree than a random tree would be (P > 0.05), thus allowing us to reject the model of virus-host coevolution.

CONCLUSION

This study presents the first evidence of PV infection in platyrrhine species from Argentina, expands the range of described hosts for these viruses, and suggests new scenarios for their origin and dispersal.

Viral Metagenomic Data Analyses of Five New World Bat Species from Argentina: Identification of 35 Novel DNA Viruses

Bats are natural reservoirs of a variety of zoonotic viruses, many of which cause severe human diseases. Characterizing viruses of bats inhabiting different geographical regions is important for understanding their viral diversity and for detecting viral spillovers between animal species. Herein, the diversity of DNA viruses of five arthropodophagous bat species from Argentina was investigated using metagenomics. Fecal samples of 29 individuals from five species (Tadarida brasiliensis, Molossus molossus, Eumops bonariensis, Eumops patagonicus, and Eptesicus diminutus) living at two different geographical locations, were investigated. Enriched viral DNA was sequenced using Illumina MiSeq, and the reads were trimmed and filtered using several bioinformatic approaches. The resulting nucleotide sequences were subjected to viral taxonomic classification. In total, 4,520,370 read pairs were sequestered by sequencing, and 21.1% of them mapped to viral taxa. Circoviridae and Genomoviridae were the most prevalent among vertebrate viral families in all bat species included in this study. Samples from the T. brasiliensis colony exhibited lower viral diversity than samples from other species of New World bats. We characterized 35 complete genome sequences of novel viruses. These findings provide new insights into the global diversity of bat viruses in poorly studied species, contributing to prevention of emerging zoonotic diseases and to conservation policies for endangered species.

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.

Bat virome research: the past, the present and the future

Bats have been increasingly recognised as an exceptional reservoir for emerging zoonotic viruses for the past few decades. Recent studies indicate that the unique bat immune system may be partially responsible for their ability to co-exist with viruses with minimal or no clinical diseases. In this review, we discuss the history and importance of bat virome studies and contrast the vast difference between such studies before and after the introduction of next generation sequencing (NGS) in this area of research. We also discuss the role of discovery serology and high-throughput single cell RNA-seq in future bat virome research.

First detection and complete genome analysis of the Lyon IARC polyomavirus in China from samples of diarrheic cats

Lyon IARC polyomavirus (LIPyV), a newly discovered polyomavirus (PyV), was first identified in 2017 in human skin samples in the USA. Later, it was detected in several other countries in samples of human and feline origin. Our aim was to find out if the virus occurs in China. To this end, 100 fecal samples were collected from cats with diarrhea in Guangxi Province during 2016 and 2018 and tested with polymerase chain reaction (PCR). Only 2 samples that originated from two related individuals were found to be positive. Based on the sequence identity of the 240-bp PCR products, the two positive samples supposedly contained identical viruses. Therefore, only one of them, which was designated as LIPyV-GXNN01, was selected for full genome amplification, cloning, sequencing and analysis. LIPyV-GXNN01, which comprises 5,263 nucleotides, has an early region that consists of small T antigen (ST-Ag) and large T antigen (LT-Ag) and a late region coding for the VP1, VP2, and VP3 structural proteins. Moreover, the LIPyV-GXNN01 strain structural proteins share 95.9–99.4%, 97.6–99.2%, and 97.1–99.2% nucleic acid identity with the VP1, VP2, and VP3of other LIPyV reference strains, respectively. A phylogenetic analysis revealed that GXNN01 clustered together with previously reported LIPyV strain. This present study is the first report of LIPyV in China.

First Report of Phodopus sungorus Papillomavirus Type 1 Infection in Roborovski Hamsters (Phodopus roborovskii)

Papillomaviruses (PVs) are considered highly species-specific with cospeciation as the main driving force in their evolution. However, a recent increase in the available PV genome sequences has revealed inconsistencies in virus–host phylogenies, which could be explained by adaptive radiation, recombination, host-switching events and a broad PV host range. Unfortunately, with a relatively low number of animal PVs characterized, understanding these incongruities remains elusive. To improve knowledge of biology and the spread of animal PV, we collected 60 swabs of the anogenital and head and neck regions from a healthy colony of 30 Roborovski hamsters (Phodopus roborovskii) and detected PVs in 44/60 (73.3%) hamster samples. This is the first report of PV infection in Roborovski hamsters. Moreover, Phodopus sungorus papillomavirus type 1 (PsuPV1), previously characterized in Siberian hamsters (Phodopus sungorus), was the only PV detected in Roborovski hamsters. In addition, after a detailed literature search, review and summary of published evidence and construction of a tanglegram linking the cladograms of PVs and their hosts, our findings were discussed in the context of available knowledge on PVs described in at least two different host species.

The characterization of two novel neotropical primate papillomaviruses supports the ancient within-species diversity model

Papillomaviruses (PVs) are non-enveloped icosahedral viruses with a circular double-stranded DNA genome of ∼8,000 base pairs (bp). More than 200 different PV types have been identified to date in humans, which are distributed in five genera, with several strains associated with cancer development. Although widely distributed in vertebrates, Neotropical Primates (NP) PV infection was described for the first time only in 2016. Currently, four complete genomes of NP PVs have been characterized, three from Saimiri sciureus (SscPV1 to SscPV3) and one from Alouatta guariba (AgPV1). In this work, we describe two novel PV strains infecting Callithrix penicillata (provisionally named CpenPV1 and CpenPV2), using anal swab samples from animals residing at the Brasilia Primatology Center and next generation sequencing. The genomes of CpenPV1 (7,288 bp; 41.5% guanine-cytosine content - GC) and CpenPV2 (7,250 bp; 40.7% GC) contain the characteristic open reading frames (ORFs) for the early (E6, E7, E1, E2, and E4) and late (L2 and L1) PV genes. The L1 ORFs, commonly used for phylogenetic identification, share 76 per cent similarity with each other and differ 32 per cent from any other known PV, indicating that these new strains meet the criteria for defining novel species. PV genes phylogenetic variance was analyzed and different degrees of saturation revealed similar levels of topological heterogeneity, ruling out saturation as primary etiological factor for this phenomenon. Interestingly, the two CpenPV strains form a monophyletic clade within the Gammapapillomavirus genus (provisionally named gammapapillomavirus 32). Unlike for other NP PV strains, which grouped into a new sister genus of Alphapapillomavirus, this is the first report of NP PV strains grouping into a genus previously considered to exclusively comprise Old World Primates (OWP) PVs, including human PVs. These findings confirm the existence of a common ancestor for Gammapapillomavirus already infecting primates before the split of OWP and NP at ∼40 million years ago. Finally, our findings are consistent with an ancient within-species diversity model and emphasize the importance of increasing sampling to help understanding the PV-primate codivergence dynamics and pathogenic potential.

A Preliminary Study of the Virome of the South American Free-Tailed Bats (Tadarida brasiliensis) and Identification of Two Novel Mammalian Viruses

Bats provide important ecosystem services as pollinators, seed dispersers, and/or insect controllers, but they have also been found harboring different viruses with zoonotic potential. Virome studies in bats distributed in Asia, Africa, Europe, and North America have increased dramatically over the past decade, whereas information on viruses infecting South American species is scarce. We explored the virome of Tadarida brasiliensis, an insectivorous New World bat species inhabiting a maternity colony in Rosario (Argentina), by a metagenomic approach. The analysis of five pooled oral/anal swab samples indicated the presence of 43 different taxonomic viral families infecting a wide range of hosts. By conventional nucleic acid detection techniques and/or bioinformatics approaches, the genomes of two novel viruses were completely covered clustering into the Papillomaviridae (Tadarida brasiliensis papillomavirus type 1, TbraPV1) and Genomoviridae (Tadarida brasiliensis gemykibivirus 1, TbGkyV1) families. TbraPV1 is the first papillomavirus type identified in this host and the prototype of a novel genus. TbGkyV1 is the first genomovirus reported in New World bats and constitutes a new species within the genus Gemykibivirus. Our findings extend the knowledge about oral/anal viromes of a South American bat species and contribute to understand the evolution and genetic diversity of the novel characterized viruses.

Genome Plasticity in Papillomaviruses and De Novo Emergence of E5 Oncogenes

The clinical presentations of papillomavirus (PV) infections come in many different flavors. While most PVs are part of a healthy skin microbiota and are not associated to physical lesions, other PVs cause benign lesions, and only a handful of PVs are associated to malignant transformations linked to the specific activities of the E5, E6, and E7 oncogenes. The functions and origin of E5 remain to be elucidated. These E5 open reading frames (ORFs) are present in the genomes of a few polyphyletic PV lineages, located between the early and the late viral gene cassettes. We have computationally assessed whether these E5 ORFs have a common origin and whether they display the properties of a genuine gene. Our results suggest that during the evolution of Papillomaviridae, at least four events lead to the presence of a long noncoding DNA stretch between the E2 and the L2 genes. In three of these events, the novel regions evolved coding capacity, becoming the extant E5 ORFs. We then focused on the evolution of the E5 genes in AlphaPVs infecting primates. The sharp match between the type of E5 protein encoded in AlphaPVs and the infection phenotype (cutaneous warts, genital warts, or anogenital cancers) supports the role of E5 in the differential oncogenic potential of these PVs. In our analyses, the best-supported scenario is that the five types of extant E5 proteins within the AlphaPV genomes may not have a common ancestor. However, the chemical similarities between E5s regarding amino acid composition prevent us from confidently rejecting the model of a common origin. Our evolutionary interpretation is that an originally noncoding region entered the genome of the ancestral AlphaPVs. This genetic novelty allowed to explore novel transcription potential, triggering an adaptive radiation that yielded three main viral lineages encoding for different E5 proteins, displaying distinct infection phenotypes. Overall, our results provide an evolutionary scenario for the de novo emergence of viral genes and illustrate the impact of such genotypic novelty in the phenotypic diversity of the viral infections.

Origin and evolution of papillomavirus (onco)genes and genomes

Papillomaviruses (PVs) are ancient viruses infecting vertebrates, from fishes to mammals. Although the genomes of PVs are small and show conserved synteny, PVs display large genotypic diversity and ample variation in the phenotypic presentation of the infection. Most PV genomes contain two small early genes E6 and E7. In a bunch of closely related human papillomaviruses (HPVs), the E6 and E7 proteins provide the viruses with oncogenic potential. The recent discoveries of PVs without E6 and E7 in different fish species place a new root on the PV tree, and suggest that ancestral PVs consisted of the minimal PV backbone E1-E2-L2-L1. Bayesian phylogenetic analyses date the most recent common ancestor of the PV backbone to 424 million years ago (Ma). Common ancestry tests on extant E6 and E7 genes indicate that they share a common ancestor dating back to at least 184 Ma. In AlphaPVs infecting Old World monkeys and apes, the appearance of the E5 oncogene 53-58 Ma concurred with (i) a significant increase in substitution rate, (ii) a basal radiation and (iii) key gain of functions in E6 and E7. This series of events was instrumental to construct the extant phenotype of oncogenic HPVs. Our results assemble the current knowledge on PV diversity and present an ancient evolutionary timeline punctuated by evolutionary innovations in the history of this successful viral family. This article is part of the theme issue 'Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses'.

New Insight Into Avian Papillomavirus Ecology and Evolution From Characterization of Novel Wild Bird Papillomaviruses

Viruses in the family Papillomaviridae have circular dsDNA genomes of approximately 5.7–8.6 kb that are packaged within non-enveloped, icosahedral capsids. The known papillomavirus (PV) representatives infect vertebrates, and there are currently more than 130 recognized PV species in more than 50 genera. We identified 12 novel avian papillomavirus (APV) types in wild birds that could represent five distinct species and two genera. Viruses were detected in paired oropharyngeal/cloacal swabs collected from six bird species, increasing the number of avian species known to harbor PVs by 40%. A new duck PV (DuPV-3) was found in mallard and American black duck (27.6% estimated prevalence) that was monophyletic with other known DuPVs. A single viral type was identified in Atlantic puffin (PuPV-1, 9.8% estimated prevalence), while a higher genetic diversity was found in other Charadriiformes. Specifically, three types [gull PV-1 (GuPV-1), -2, and -3] were identified in two gull species (estimated prevalence of 17% and 2.6% in American herring and great black-backed gull, respectively), and seven types [kittiwake PV-1 (KiPV-1) through -7] were found in black-legged kittiwake (81.3% estimated prevalence). Significantly higher DuPV-3 circulation was observed in spring compared to fall and in adults compared to juveniles. The studied host species’ tendencies to be in crowded environments likely affect infection rates and their migratory behaviors could explain the high viral diversity, illustrating how host behavior can influence viral ecology and distribution. For DuPV-3, GuPV-1, PuPV-1, and KiPV-2, we obtained the complete genomic sequences, which showed the same organization as other known APVs. Phylogenetic analyses showed evidence for virus–host co-divergence at the host taxonomic levels of family, order, and inter-order, but we also observed that host-specificity constraints are relaxed among highly related hosts as we found cross-species transmission within ducks and within gulls. Furthermore, the phylogeny of viruses infecting the Charadriiformes did not match the host phylogeny and gull viruses formed distinct monophyletic clades with kittiwake viruses, possibly reflecting past host-switching events. Considering the vast PV genotype diversity in other hosts and the large number of bird species, many more APVs likely remain to be discovered.

Detection of adenovirus, papillomavirus and parvovirus in Brazilian bats of the species Artibeus lituratus and Sturnira lilium

Bats play a significant role in maintaining their ecosystems through pollination, dispersal of seeds, and control of insect populations, but they are also known to host many microorganisms and have been described as natural reservoirs for viruses with zoonotic potential. The diversity of viruses in these animals remains largely unknown, however, because studies are limited by species, location, virus target, or sample type. Therefore, the aim of this study was to detect fragments of viral genomes in bat samples. We performed high-throughput sequencing analysis and specific PCR and RT-PCR on pools of anal and oropharyngeal swabs from Artibeus lituratus and Sturnira lilium collected in southern Brazil. As a result, a member of the family Adenoviridae related to human adenovirus C was detected in anal swabs from S. lilium. In addition, we detected a papillomavirus in an anal swab from A. lituratus. Our analyses also allowed the detection of adenoviruses and parvoviruses in oropharyngeal swabs collected from A. lituratus. These results increase our knowledge about viral diversity and illustrate the importance of conducting virus surveillance in bats.

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.

Genomic sequencing of a virus representing a novel type within the species Dyopipapillomavirus 1 in an Indian River Lagoon bottlenose dolphin

Fecal samples collected from free-ranging Atlantic bottlenose dolphins (BDs) in the Indian River Lagoon of Florida were processed for viral discovery using a next-generation sequencing (NGS) approach. A 693-bp contig identified in the NGS data was nearly identical to the partial L1 gene sequence of a papillomavirus (PV) previously found in a penile papilloma in a killer whale (Orcinus orca). Based on this partial bottlenose dolphin papillomavirus (BDPV) sequence, a nested inverse PCR and primer-walking strategy was employed to generate the complete genome sequence. The full BDPV genome consisted of 7299 bp and displayed a typical PV genome organization. The BDPV E6 protein contained a PDZ-binding motif, which has been shown to be involved in carcinogenic transformation involving high-risk genital human PVs. Screening of 12 individual fecal samples using a specific endpoint PCR assay revealed that the feces from a single female BD displaying a genital papilloma was positive for the BDPV. Genetic analysis indicated that this BDPV (Tursiops truncatus papillomavirus 8; TtPV8) is a new type of Dyopipapillomavirus 1, previously sequenced from an isolate obtained from a penile papilloma in a harbor porpoise (Phocoena phocoena). Although only a partial L1 sequence has been determined for a PV detected in a killer whale genital papilloma, our finding of a nearly identical sequence in an Atlantic BD may indicate that members of this viral species are capable of host jumping. Future work is needed to determine if this virus is a high-risk PV that is capable of inducing carcinogenic transformation and whether it poses a significant health risk to wild delphinid populations.

Molecular identification of Betacoronavirus in bats from Sardinia (Italy): first detection and phylogeny

Bats may be natural reservoirs for a large variety of emerging viruses, including mammalian coronaviruses (CoV). The recent emergence of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) in humans, with evidence that these viruses may have their ancestry in bats, highlights the importance of virus surveillance in bat populations. Here, we report the identification and molecular characterization of a bat β-Coronavirus, detected during a viral survey carried out on different bat species in the island of Sardinia (Italy). Cutaneous, oral swabs, and faecal samples were collected from 46 bats, belonging to 15 different species, and tested for viral presence. Coronavirus RNA was detected in faecal samples from three different species: the greater horseshoe bat (Rhinolophus ferrumequinum), the brown long-eared bat (Plecotus auritus), and the European free-tailed bat (Tadarida teniotis). Phylogenetic analyses based on RNA-dependent RNA polymerase (RdRp) sequences assigned the detected CoV to clade 2b within betacoronaviruses, clustering with SARS-like bat CoVs previously reported. These findings point to the need for continued surveillance of bat CoV circulating in Sardinian bats, and extend the current knowledge on CoV ecology with novel sequences detected in bat species not previously described as β-Coronavirus hosts.

Genomic characterization of Erethizon dorsatum papillomavirus 2, a new papillomavirus species marked by its exceptional genome size

We report here the complete sequence and genome organization of a new papillomavirus, Erethizon dorsatum papillomavirus 2 (EdPV2), which was isolated from cutaneous lesions observed on the muzzle of a North American porcupine. The complete genome is 8809 nucleotides long and encodes five early (E6-E7-E1-E2-E4) and two late proteins (L2-L1). In addition to the upstream regulatory region, the EdPV2 genome contains an exceptionally large secondary non-coding region with no apparent functional relevance. EdPV2 is strongly divergent from the previously described porcupine papillomavirus EdPV1 and phylogenetic analysis shows EdPV2 clustering near members of the genus Pipapillomavirus, a group of rodent papillomaviruses. Pairwise sequence comparison based on the L1 open reading frame identifies Rattus norvegicus papillomavirus 1 as the closest related virus (59.97 % similarity). Based on its low sequence similarity to other known papillomaviruses, EdPV2 is thought to represent a new genus in the family Papillomaviridae.

Spatio-temporal dynamics and aetiology of proliferative leg skin lesions in wild British finches

Proliferative leg skin lesions have been described in wild finches in Europe although there have been no large-scale studies of their aetiology or epizootiology to date. Firstly, disease surveillance, utilising public reporting of observations of live wild finches was conducted in Great Britain (GB) and showed proliferative leg skin lesions in chaffinches (Fringilla coelebs) to be widespread. Seasonal variation was observed, with a peak during the winter months. Secondly, pathological investigations were performed on a sample of 39 chaffinches, four bullfinches (Pyrrhula pyrrhula), one greenfinch (Chloris chloris) and one goldfinch (Carduelis carduelis) with proliferative leg skin lesions and detected Cnemidocoptes sp. mites in 91% (41/45) of affected finches and from all species examined. Fringilla coelebs papillomavirus (FcPV1) PCR was positive in 74% (23/31) of birds tested: a 394 base pair sequence was derived from 20 of these birds, from all examined species, with 100% identity to reference genomes. Both mites and FcPV1 DNA were detected in 71% (20/28) of birds tested for both pathogens. Histopathological examination of lesions did not discriminate the relative importance of mite or FcPV1 infection as their cause. Development of techniques to localise FcPV1 within lesions is required to elucidate the pathological significance of FcPV1 DNA detection.

Crystal structure and functional analysis of human C1ORF123

Proteins of the DUF866 superfamily are exclusively found in eukaryotic cells. A member of the DUF866 superfamily, C1ORF123, is a human protein found in the open reading frame 123 of chromosome 1. The physiological role of C1ORF123 is yet to be determined. The only available protein structure of the DUF866 family shares just 26% sequence similarity and does not contain a zinc binding motif. Here, we present the crystal structure of the recombinant human C1ORF123 protein (rC1ORF123). The structure has a 2-fold internal symmetry dividing the monomeric protein into two mirrored halves that comprise of distinct electrostatic potential. The N-terminal half of rC1ORF123 includes a zinc-binding domain interacting with a zinc ion near to a potential ligand binding cavity. Functional studies of human C1ORF123 and its homologue in the fission yeast Schizosaccharomyces pombe (SpEss1) point to a role of DUF866 protein in mitochondrial oxidative phosphorylation.

Generation of a novel next-generation sequencing-based method for the isolation of new human papillomavirus types

With the advent of new molecular tools, the discovery of new papillomaviruses (PVs) has accelerated during the past decade, enabling the expansion of knowledge about the viral populations that inhabit the human body. Human PVs (HPVs) are etiologically linked to benign or malignant lesions of the skin and mucosa. The detection of HPV types can vary widely, depending mainly on the methodology and the quality of the biological sample. Next-generation sequencing is one of the most powerful tools, enabling the discovery of novel viruses in a wide range of biological material. Here, we report a novel protocol for the detection of known and unknown HPV types in human skin and oral gargle samples using improved PCR protocols combined with next-generation sequencing. We identified 105 putative new PV types in addition to 296 known types, thus providing important information about the viral distribution in the oral cavity and skin.

Ancient DNA provides evidence of 27,000-year-old papillomavirus infection and long-term codivergence with rodents

The long-term evolutionary history of many viral lineages is poorly understood. Novel sources of ancient DNA combined with phylogenetic analyses can provide insight into the time scale of virus evolution. Here we report viral sequences from ancient North American packrat middens. We screened samples up to 27,000-years old and found evidence of papillomavirus (PV) infection in Neotoma cinerea (Bushy-tailed packrat). Phylogenetic analysis placed the PV sequences in a clade with other previously published PV sequences isolated from rodents. Concordance between the host and virus tree topologies along with a correlation in branch lengths suggests a shared evolutionary history between rodents and PVs. Based on host divergence times, PVs have likely been circulating in rodents for at least 17 million years. These results have implications for our understanding of PV evolution and for further research with ancient DNA from Neotoma middens.

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.

Molecular characterization, prevalence and clinical relevance of Phodopus sungorus papillomavirus type 1 (PsuPV1) naturally infecting Siberian hamsters (Phodopus sungorus)

Phodopus sungorus papillomavirus type 1 (PsuPV1), naturally infecting Siberian hamsters (Phodopus sungorus) and clustering in the genus Pipapillomavirus (Pi-PV), is only the second PV type isolated from the subfamily of hamsters. In silico analysis of three independent complete viral genomes obtained from cervical adenocarcinoma, oral squamous cell carcinoma and normal oral mucosa revealed that PsuPV1 encodes characteristic viral proteins (E1, E2, E4, E6, E7, L1 and L2) with conserved functional domains and a highly conserved non-coding region. The overall high prevalence (102/114; 89.5 %) of PsuPV1 infection in normal oral and anogenital mucosa suggests that asymptomatic infection with PsuPV1 is very frequent in healthy Siberian hamsters from an early age onward, and that the virus is often transmitted between both anatomical sites. Using type-specific real-time PCR and chromogenic in situ hybridization, the presence of PsuPV1 was additionally detected in several investigated tumours (cervical adenocarcinoma, cervical adenomyoma, vaginal carcinoma in situ, ovarian granulosa cell tumour, mammary ductal carcinoma, oral fibrosarcoma, hibernoma and squamous cell papilloma) and normal tissues of adult animals. In the tissue sample of the oral squamous cell carcinoma individual, punctuated PsuPV1-specific in situ hybridization spots were detected within the nuclei of infected animal cells, suggesting viral integration into the host genome and a potential etiological association of PsuPV1 with sporadic cases of this neoplasm.

Identification of the same polyomavirus species in different African horseshoe bat species is indicative of short-range host-switching events

Polyomaviruses (PyVs) are considered to be highly host-specific in different mammalian species, with no well-supported evidence for host-switching events. We examined the species diversity and host specificity of PyVs in horseshoe bats (Rhinolophus spp.), a broadly distributed and highly speciose mammalian genus. We annotated six PyV genomes, comprising four new PyV species, based on pairwise identity within the large T antigen (LTAg) coding region. Phylogenetic comparisons revealed two instances of highly related PyV species, one in each of the Alphapolyomavirus and Betapolyomavirus genera, present in different horseshoe bat host species (Rhinolophus blasii and R. simulator), suggestive of short-range host-switching events. The two pairs of Rhinolophus PyVs in different horseshoe bat host species were 99.9 and 88.8 % identical with each other over their respective LTAg coding sequences and thus constitute the same virus species. To corroborate the species identification of the bat hosts, we analysed mitochondrial cytb and a large nuclear intron dataset derived from six independent and neutrally evolving loci for bat taxa of interest. Bayesian estimates of the ages of the most recent common ancestors suggested that the near-identical and more distantly related PyV species diverged approximately 9.1E4 (5E3-2.8E5) and 9.9E6 (4E6-18E6) years before the present, respectively, in contrast to the divergence times of the bat host species: 12.4E6 (10.4E6-15.4E6). Our findings provide evidence that short-range host-switching of PyVs is possible in horseshoe bats, suggesting that PyV transmission between closely related mammalian species can occur.

Viral metagenomics of six bat species in close contact with humans in southern China

Accumulating studies have shown that bats could harbor various important pathogenic viruses that could be transmitted to humans and other animals. Extensive metagenomic studies of different organs/tissues from bats have revealed a large number of novel or divergent viruses. To elucidate viral diversity and epidemiological and phylogenetic characteristics, six pooled fecal samples from bats were generated (based on bat species and geographic regions characteristic for virome analysis). These contained 500 fecal samples from six bat species, collected in four geographic regions. Metagenomic analysis revealed a plethora of divergent viruses originally found in bats. Multiple contigs from influenza A virus and coronaviruses in bats shared high identity with those from humans, suggesting possible cross-species transmission, whereas a number of contigs, whose sequences were taxonomically classifiable within Alphapapillomavirus, Betaretrovirus, Alpharetrovirus, Varicellovirus, Cyprinivirus, Chlorovirus and Cucumovirus had low identity to viruses in existing databases, which indicated possible evolution of novel viral species. None of the established caliciviruses and picornaviruses were found in the 500 fecal specimens. Papillomaviruses with high amino acid identity were found in Scotophilus kuhlii and Rhinolophus blythi, challenging the hypotheses regarding the strict host specificity and co-evolution of papillomaviruses. Phylogenetic analysis showed that four bat rotavirus A strains might be tentative G3 strains, according to the Rotavirus Classification Working Group classification.

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.

Assessing Host-Virus Codivergence for Close Relatives of Merkel Cell Polyomavirus Infecting African Great Apes

It has long been hypothesized that polyomaviruses (PyV; family Polyomaviridae) codiverged with their animal hosts. In contrast, recent analyses suggested that codivergence may only marginally influence the evolution of PyV. We reassess this question by focusing on a single lineage of PyV infecting hominine hosts, the Merkel cell polyomavirus (MCPyV) lineage. By characterizing the genetic diversity of these viruses in seven African great ape taxa, we show that they exhibit very strong host specificity. Reconciliation analyses identify more codivergence than noncodivergence events. In addition, we find that a number of host and PyV divergence events are synchronous. Collectively, our results support codivergence as the dominant process at play during the evolution of the MCPyV lineage. More generally, our results add to the growing body of evidence suggesting an ancient and stable association of PyV and their animal hosts.

IMPORTANCE

The processes involved in viral evolution and the interaction of viruses with their hosts are of great scientific interest and public health relevance. It has long been thought that the genetic diversity of double-stranded DNA viruses was generated over long periods of time, similar to typical host evolutionary timescales. This was also hypothesized for polyomaviruses (family Polyomaviridae), a group comprising several human pathogens, but this remains a point of controversy. Here, we investigate this question by focusing on a single lineage of polyomaviruses that infect both humans and their closest relatives, the African great apes. We show that these viruses exhibit considerable host specificity and that their evolution largely mirrors that of their hosts, suggesting that codivergence with their hosts played a major role in their diversification. Our results provide statistical evidence in favor of an association of polyomaviruses and their hosts over millions of years.

Searching beyond the usual papillomavirus suspects in squamous carcinomas of the vulva, penis and head and neck

Human Papillomaviruses (HPVs) are involved in the etiology of anogenital and head and neck cancers. The HPV DNA prevalence greatly differs by anatomical site. Indeed, the high rates of viral DNA prevalence in anal and cervical carcinomas contrast with the lower fraction of cancer cases attributable to HPVs in other anatomical sites, chiefly the vulva, the penis and head and neck. Here we analyzed 2635 Formalin Fixed Paraffin Embedded surgical samples that had previously tested negative for the presence of HPVs DNA using the SPF10/DEIA procedure, in order to identify the presence of other PVs not explicitly targeted by standard molecular epidemiologic approaches. All samples were reanalyzed using five broad-PV PCR primer sets (CP1/2, FAP6064/FAP64, SKF/SKR, MY9/MY11, MFI/MFII) targeting the main PV main clades. In head and neck carcinoma samples (n=1141), we recovered DNA from two BetaHPVs, namely HPV20 and HPV21, and from three cutaneous AlphaPVs, namely HPV2, HPV57 and HPV61. In vulvar squamous cell carcinoma samples (n=902), we found one of the samples containing DNA of one cutaneous HPV, namely HPV2, and 29 samples contained DNA from essentially mucosal HPVs. In penile squamous cell carcinoma samples (n=592), we retrieved the DNA of HPV16 in 16 samples. Our results show first that the SPF10/DEIA is very sensitive, as we recovered only 2.1% (55/2635) false negative results; second, that although the DNA of cutaneous HPVs can be detected in cancer samples, their relative contribution remains anyway minor (0.23%; 6/2635) and may be neglected for screening and vaccination purposes; and third, their contribution to malignancy is not necessarily warranted and needs to be elucidated.

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.

A single bat species in Cameroon harbors multiple highly divergent papillomaviruses in stool identified by metagenomics analysis

A number of PVs have been described in bats but to the best of our knowledge not from feces. Using a previously described NetoVIR protocol, Eidolon helvum pooled fecal samples (Eh) were treated and sequenced by Illumina next generation sequencing technology. Two complete genomes of novel PVs (EhPV2 and EhPV3) and 3 partial sequences (BATPV61, BATPV890a and BATPV890b) were obtained and analysis showed that the EhPV2 and EhPV3 major capsid proteins cluster with and share 60-64% nucleotide identity with that of Rousettus aegyptiacus PV1, thus representing new species of PVs within the genus Psipapillomavirus. The other PVs clustered in different branches of our phylogenetic tree and may potentially represent novel species and/or genera. This points to the vast diversity of PVs in bats and in Eidolon helvum bats in particular, therefore adding support to the current concept that PV evolution is more complex than merely strict PV-host co-evolution.

Characterization of novel human papillomavirus types 157, 158 and 205 from healthy skin and recombination analysis in genus γ-Papillomavirus

Gammapapillomavirus (γ-PV) is a diverse and rapidly expanding genus, currently consisting of 79 fully characterized human PV (HPV) types. In this study, three novel types, HPV157, HPV158 and HPV205, obtained from healthy sun-exposed skin of two immunocompetent individuals, were amplified by the "Hanging droplet" long PCR technique, cloned, sequenced and characterized. HPV157, HPV158 and HPV205 genomes comprise 7154-bp, 7192-bp and 7298-bp, respectively, and contain four early (E1, E2, E6 and E7) and two late genes (L1 and L2). Phylogenetic analysis of the L1 ORF placed all novel types within the γ-PV genus: HPV157 was classified as a new member of species γ-12 while HPV158 and HPV205 belong to species γ-1. We then explored potential recombination events in genus γ-PV with the RDP4 program in a dataset of 74 viruses (71 HPV types with available full-length genomes and the 3 novel types). Two events, both located in the E1 ORF, met the inclusion criterion (p-values <0.05 with at least four methods) and persisted in different ORF combinations: an inter-species recombination in species γ-8 (major and minor parents: species γ-24 and γ-11, respectively), and an intra-species recombination in species γ-7 (recombinant strain: HPV170; major and minor parents: HPV-109 and HPV-149, respectively). These findings were confirmed by phylogenetic tree incongruence analysis. An additional incongruence was found in members of species γ-9 but it was not detected by the RDP4. This report expands our knowledge of the family Papillomaviridae and provides for the first time in silico evidence of recombination in genus γ-PV.

Bovine papillomavirus type 7 in Italy: complete genomes and sequence variants

Two novel bovine papillomavirus type 7 (BPV-7) variants have been identified in teat cutaneous papillomas affecting dairy cows in northern Italy. The entire genome sequences of two BPV-7 Italian variants showed major sequence differences in the long control region (LCR) and in the L2 gene compared to the Japanese reference strain. In order to define the stability of these genetic variants, the L2 and LCR sequences of seven further BPV-7 positive isolates were characterized. An insertion of six amino acids in the L2 structural protein has been detected in all samples while different genetic variants have been identified for the LCR. These findings provide new insights on intra-type variability of BPVs and represent a starting point for future studies aimed at establishing the biological role of the different BPV genomic regions and investigating the pathogenic potential of papillomavirus variants.

Non-invasive monitoring of stress hormones in the bat Eptesicus isabellinus - Do fecal glucocorticoid metabolite concentrations correlate with survival?

Chronic stress may negatively impact fitness and survival in wildlife. Stress hormone analysis from feces is a non-invasive tool for identifying stressors and deducing about individual and population level fitness. Although many bat populations are endangered, fecal stress hormone analysis has not been established in bats as a method for focusing conservation efforts. The isabelline serotine bat, Eptesicus isabellinus, is exposed to human disturbance as its roosts are mostly found in anthropogenic structures. Moreover, this bat is host to various diseases and survival rates between colonies may vary significantly. To validate the analysis of fecal glucocorticoid metabolites, we applied an adrenocorticotropic hormone (ACTH) challenge and tested four different enzyme immunoassays (EIA) for measuring glucocorticoid concentrations. Cortisol and its metabolites showed the highest increase in blood and feces after the ACTH challenge, but corticosterone and its metabolites also increased significantly. Baseline fecal cortisol metabolite (FCM) concentrations did not increase until 1.5h after the animals were captured, which is a convenient time lag for sample collection from captured animals. We furthermore compared baseline FCM concentrations between five colonies of E. isabellinus in Andalusia, Spain, and tested for their correlation with survival rates. FCM concentrations did not vary between colonies, but FCM levels increased with the animals' age. FCM analysis may prove a useful tool for identifying bat colonies that experience uncommon environmental stress. However, inter-individual variation in hormone secretion, due to factors such as age, may require additional information to properly interpret differences in hormone concentrations.

Deciphering the bat virome catalog to better understand the ecological diversity of bat viruses and the bat origin of emerging infectious diseases

Studies have demonstrated that ~60%–80% of emerging infectious diseases (EIDs) in humans originated from wild life. Bats are natural reservoirs of a large variety of viruses, including many important zoonotic viruses that cause severe diseases in humans and domestic animals. However, the understanding of the viral population and the ecological diversity residing in bat populations is unclear, which complicates the determination of the origins of certain EIDs. Here, using bats as a typical wildlife reservoir model, virome analysis was conducted based on pharyngeal and anal swab samples of 4440 bat individuals of 40 major bat species throughout China. The purpose of this study was to survey the ecological and biological diversities of viruses residing in these bat species, to investigate the presence of potential bat-borne zoonotic viruses and to evaluate the impacts of these viruses on public health. The data obtained in this study revealed an overview of the viral community present in these bat samples. Many novel bat viruses were reported for the first time and some bat viruses closely related to known human or animal pathogens were identified. This genetic evidence provides new clues in the search for the origin or evolution pattern of certain viruses, such as coronaviruses and noroviruses. These data offer meaningful ecological information for predicting and tracing wildlife-originated EIDs.

A Century of Shope Papillomavirus in Museum Rabbit Specimens

Sylvilagus floridanus Papillomavirus (SfPV) causes growth of large horn-like tumors on rabbits. SfPV was described in cottontail rabbits (probably Sylvilagus floridanus) from Kansas and Iowa by Richard Shope in 1933, and detected in S. audubonii in 2011. It is known almost exclusively from the US Midwest. We explored the University of Kansas Natural History Museum for historical museum specimens infected with SfPV, using molecular techniques, to assess if additional wild species host SfPV, and whether SfPV occurs throughout the host range, or just in the Midwest. Secondary aims were to detect distinct strains, and evidence for strain spatio-temporal specificity. We found 20 of 1395 rabbits in the KU collection SfPV symptomatic. Three of 17 lagomorph species (S. nuttallii, and the two known hosts) were symptomatic, while Brachylagus, Lepus and eight additional Sylvilagus species were not. 13 symptomatic individuals were positive by molecular testing, including the first S. nuttallii detection. Prevalence of symptomatic individuals was significantly higher in Sylvilagus (1.8%) than Lepus. Half of these specimens came from Kansas, though new molecular detections were obtained from Jalisco—Mexico’s first—and Nebraska, Nevada, New Mexico, and Texas, USA. We document the oldest lab-confirmed case (Kansas, 1915), pre-dating Shope’s first case. SfPV amplification was possible from 63.2% of symptomatic museum specimens. Using multiple methodologies, rolling circle amplification and, multiple isothermal displacement amplification in addition to PCR, greatly improved detection rates. Short sequences were obtained from six individuals for two genes. L1 gene sequences were identical to all previously detected sequences; E7 gene sequences, were more variable, yielding five distinct SfPV1 strains that differing by less than 2% from strains circulating in the Midwest and Mexico, between 1915 and 2005. Our results do not clarify whether strains are host species specific, though they are consistent with SfPV specificity to genus Sylvilagus.

Papillomaviruses: Viral evolution, cancer and evolutionary medicine

Papillomaviruses (PVs) are a numerous family of small dsDNA viruses infecting virtually all mammals. PVs cause infections without triggering a strong immune response, and natural infection provides only limited protection against reinfection. Most PVs are part and parcel of the skin microbiota. In some cases, infections by certain PVs take diverse clinical presentations from highly productive self-limited warts to invasive cancers. We propose PVs as an excellent model system to study the evolutionary interactions between the immune system and pathogens causing chronic infections: genotypically, PVs are very diverse, with hundreds of different genotypes infecting skin and mucosa; phenotypically, they display extremely broad gradients and trade-offs between key phenotypic traits, namely productivity, immunogenicity, prevalence, oncogenicity and clinical presentation. Public health interventions have been launched to decrease the burden of PV-associated cancers, including massive vaccination against the most oncogenic human PVs, as well as systematic screening for PV chronic anogenital infections. Anti-PVs vaccines elicit protection against infection, induce cross-protection against closely related viruses and result in herd immunity. However, our knowledge on the ecological and intrapatient dynamics of PV infections remains fragmentary. We still need to understand how the novel anthropogenic selection pressures posed by vaccination and screening will affect viral circulation and epidemiology. We present here an overview of PV evolution and the connection between PV genotypes and the phenotypic, clinical manifestations of the diseases they cause. This differential link between viral evolution and the gradient cancer-warts-asymptomatic infections makes PVs a privileged playground for evolutionary medicine research.

A large spectrum of alpha and beta papillomaviruses are detected in human stool samples

Human papillomaviruses (HPVs) have been detected in urban wastewaters, demonstrating that epitheliotropic viruses can find their way into sewage through the washing of skin and mucous membranes. Papillomavirus shedding through faeces is still an unexplored issue. The objective of the present study was to investigate the presence of HPVs in stool samples. We analysed 103 faecal specimens collected from hospitalized patients with diarrhoea using validated primers able to detect α, β and γ HPVs. PCR products underwent sequencing analysis and sequences were aligned to reference genomes from the Papillomavirus Episteme database. A total of 15 sequences were characterized from the faecal samples. Thirteen samples (12.6 %) were positive for nine genotypes belonging to the α and β genera: HPV32 (LR, α1), HPV39 (HR, α7), HPV44 (LR, α10), HPV8 (β1), HPV9, HPV23, HPV37, HPV38 and HPV120 (β2). Two putative novel genotypes of the β genus, species 1 and 2, were also detected. The tissue(s) of origin is unknown, since faeces can collect HPVs originating from or passing through the entire digestive system. To our knowledge, this is the first investigation on the occurrence and diversity of HPVs in faecal samples. Results from this study demonstrate that HPVs can find their way into sewage as a consequence of shedding in the faeces. This highlights the need for further studies aimed at understanding the prevalence of HPV in different water environments and the potential for waterborne transmission.

Analysis of the long control region of bovine papillomavirus type 1 associated with sarcoids in equine hosts indicates multiple cross-species transmission events and phylogeographical structure

Papillomaviruses are a family of slowly evolving DNA viruses and their evolution is commonly linked to that of their host species. However, whilst bovine papillomavirus-1 (BPV-1) primarily causes warts in its natural host, the cow, it can also cause locally aggressive and invasive skin tumours in equids, known as sarcoids, and thus provides a rare contemporary example of cross-species transmission of a papillomavirus. Here, we describe the first phylogenetic analysis of BPV-1 in equine sarcoids to our knowledge, allowing us to explore the evolutionary history of BPV-1 and investigate its cross-species association with equids. A phylogenetic analysis of the BPV-1 transcriptional promoter region (the long control region or LCR) was conducted on 15 bovine and 116 equine samples from four continents. Incorporating previous estimates for evolutionary rates in papillomavirus implied that the genetic diversity in the LCR variants was ancient and predated domestication of both equids and cattle. The phylogeny demonstrated geographical segregation into an ancestral group (African, South American and Australian samples), and a more recently derived, largely European clade. Whilst our data are consistent with BPV-1 originating in cattle, we found evidence of multiple, probably relatively recent, cross-species transmission events into horses. We also demonstrated the high prevalence of one particular sequence variant (variant 20), and suggest this may indicate that this variant shows a fitness advantage in equids. Although strong host specificity remains the norm in papillomaviruses, our results demonstrate that exceptions to this rule exist and can become epidemiologically relevant.

European bats as carriers of viruses with zoonotic potential

Bats are being increasingly recognized as reservoir hosts of highly pathogenic and zoonotic emerging viruses (Marburg virus, Nipah virus, Hendra virus, Rabies virus, and coronaviruses). While numerous studies have focused on the mentioned highly human-pathogenic bat viruses in tropical regions, little is known on similar human-pathogenic viruses that may be present in European bats. Although novel viruses are being detected, their zoonotic potential remains unclear unless further studies are conducted. At present, it is assumed that the risk posed by bats to the general public is rather low. In this review, selected viruses detected and isolated in Europe are discussed from our point of view in regard to their human-pathogenic potential. All European bat species and their roosts are legally protected and some European species are even endangered. Nevertheless, the increasing public fear of bats and their viruses is an obstacle to their protection. Educating the public regarding bat lyssaviruses might result in reduced threats to both the public and the bats.