Genome Sequences of a Rat Polyomavirus Related to Murine Polyomavirus, Rattus norvegicus Polyomavirus 1

Complete genome characterization and phylogenetic analysis of a novel polyomavirus detected in Eurasian beavers (Castor fiber)

The Eurasian beaver (Castor fiber), native to Hungary, faced local extinction in 1865 and was successfully reintroduced between mid-1980s and 2008. Despite screening programs focusing on animal health during reintroduction in other countries, information about viruses in the Hungarian beaver population remains limited. Polyomaviruses (PyVs) have been identified in various rodents, and have been detected just recently in beavers by us. In this paper we present the full genome analysis of the first PyV detected in Eurasian beaver. The novel PyV was discovered in the kidney tissues of two specimens. The genome is 5244 bp, and contains four genes. Small T-antigen (STAg) and alternative large T ORF (ALTO) genes are directly fused together forming the middle T-antigen (MTAg). VP3 is absent from the genome. Its large T-antigen (LTAg) coding sequence exhibited over 15% genetic divergence from known PyVs, supporting its classification into a new species within the genus Alphapolyomavirus, suggesting to be named Alphapolyomavirus castoris. Phylogenetic analysis, based on the LTAg gene showed, that the beaver PyV forms a distinct clade with primate PyVs within the genus Alphapolyomavirus, separate from other rodent PyVs. Phylogenetic study of the VP1 gene however showed this virus to belong in a distinct clade with the same primate PyVs, and additionally PyVs from rodents and a myocastor, which suggest host virus co-evolution. The virus detection of the euthanized beavers suggests an apathogenic persistent infections. The aquatic lifestyle of beavers may influence virus transmission, warranting further exploration of undiscovered viruses in beavers.

Physiological strategies in wild rodents: immune defenses of commensal rats

The importance of issues associated with urban/commensal rats and mice (property damage, management costs, and health risks) press upon research on these animals. While the demography of commensal rodents is mostly studied, the need for understanding factors influencing their natural morbidity/mortality is also stressed. In this respect, more attention is expected to be paid to immunity, the physiological mechanism of defense against host survival threats (pathogens, parasites, diseases). Commensal rats and mice carry numerous pathogens that evoke diverse immune responses. The state of immunity in commensal house mice is studied in great detail, owing to the use of laboratory strains in biomedical research. Because commensal rats are, compared to mice, carriers of more zoonotic agents, rats' immunity is studied mainly in that context. Some of these zoonotic agents cause chronic, asymptomatic infections, which justified studies of immunological mechanisms of pathogen tolerance versus clearance regulation in rats. Occurrence of some infections in specific tissues/organs pressed upon analysis of local/regional immune responses and/or immunopathology. A survey of immunological activity/responses in commensal rats is given in this review, with mention of existing data in commensal mice. It should throw some light on the factors relevant to their morbidity and lifespan, supplementing the knowledge of commensal rodent ecology.

Presence and Diversity of Different Enteric Viruses in Wild Norway Rats (Rattus norvegicus)

Rodents are common reservoirs for numerous zoonotic pathogens, but knowledge about diversity of pathogens in rodents is still limited. Here, we investigated the occurrence and genetic diversity of enteric viruses in 51 Norway rats collected in three different countries in Europe. RNA of at least one virus was detected in the intestine of 49 of 51 animals. Astrovirus RNA was detected in 46 animals, mostly of rat astroviruses. Human astrovirus (HAstV-8) RNA was detected in one, rotavirus group A (RVA) RNA was identified in eleven animals. One RVA RNA could be typed as rat G3 type. Rat hepatitis E virus (HEV) RNA was detected in five animals. Two entire genome sequences of ratHEV were determined. Human norovirus RNA was detected in four animals with the genotypes GI.P4-GI.4, GII.P33-GII.1, and GII.P21. In one animal, a replication competent coxsackievirus A20 strain was detected. Additionally, RNA of an enterovirus species A strain was detected in the same animal, albeit in a different tissue. The results show a high detection rate and diversity of enteric viruses in Norway rats in Europe and indicate their significance as vectors for zoonotic transmission of enteric viruses. The detailed role of Norway rats and transmission pathways of enteric viruses needs to be investigated in further studies.

Hamster Polyomavirus Research: Past, Present, and Future

Hamster polyomavirus (Mesocricetus auratus polyomavirus 1, HaPyV) was discovered as one of the first rodent polyomaviruses at the end of the 1960s in a colony of Syrian hamsters (Mesocricetus auratus) affected by skin tumors. Natural HaPyV infections have been recorded in Syrian hamster colonies due to the occurrence of skin tumors and lymphomas. HaPyV infections of Syrian hamsters represent an important and pioneering tumor model. Experimental infections of Syrian hamsters of different colonies are still serving as model systems (e.g., mesothelioma). The observed phylogenetic relationship of HaPyV to murine polyomaviruses within the genus Alphapolyomavirus, and the exclusive detection of other cricetid polyomaviruses, i.e., common vole (Microtus arvalis polyomavirus 1) and bank vole (Myodes glareolus polyomavirus 1) polyomaviruses, in the genus Betapolyomavirus, must be considered with caution, as knowledge of rodent-associated polyomaviruses is still limited. The genome of HaPyV shows the typical organization of polyomaviruses with an early and a late transcriptional region. The early region encodes three tumor (T) antigens including a middle T antigen; the late region encodes three capsid proteins. The major capsid protein VP1 of HaPyV was established as a carrier for the generation of autologous, chimeric, and mosaic virus-like particles (VLPs) with a broad range of applications, e.g., for the production of epitope-specific antibodies. Autologous VLPs have been applied for entry and maturation studies of dendritic cells. The generation of chimeric and mosaic VLPs indicated the high flexibility of the VP1 carrier protein for the insertion of foreign sequences. The generation of pseudotype VLPs of original VP1 and VP2–foreign protein fusion can further enhance the applicability of this system. Future investigations should evaluate the evolutionary origin of HaPyV, monitor its occurrence in wildlife and Syrian hamster breeding, and prove its value for the generation of potential vaccine candidates and as a gene therapy vehicle.

Viral Disease

This chapter discusses infections of rats with viruses in the following 14 virus families: Adenoviridae, Arenaviridae, Coronaviridae, Flaviviridae, Hantaviridae, Hepeviridae, Herpesviridae, Paramyxoviridae, Parvoviridae, Picornaviridae, Pneumoviridae, Polyomaviridae, Poxviridae, and Reoviridae . Serological surveys indicate that parvoviruses, coronaviruses, cardioviruses, and pneumoviruses are the most prevalent in laboratory rats. A new polyomavirus and a new cardiovirus that cause disease in laboratory rats are described. Metagenomic analyses of feces or intestinal contents from wild rats have detected viruses from an additional nine virus families that could potentially cause infections in laboratory rats.

Codon usage patterns of LT-Ag genes in polyomaviruses from different host species

Background

Polyomaviruses (PyVs) have a wide range of hosts, from humans to fish, and their effects on hosts vary. The differences in the infection characteristics of PyV with respect to the host are assumed to be influenced by the biochemical function of the LT-Ag protein, which is related to the cytopathic effect and tumorigenesis mechanism via interaction with the host protein.

Methods

We carried out a comparative analysis of codon usage patterns of large T-antigens (LT-Ags) of PyVs isolated from various host species and their functional domains and sequence motifs. Parity rule 2 (PR2) and neutrality analysis were applied to evaluate the effects of mutation and selection pressure on codon usage bias. To investigate evolutionary relationships among PyVs, we carried out a phylogenetic analysis, and a correspondence analysis of relative synonymous codon usage (RSCU) values was performed.

Results

Nucleotide composition analysis using LT-Ag gene sequences showed that the GC and GC3 values of avian PyVs were higher than those of mammalian PyVs. The effective number of codon (ENC) analysis showed host-specific ENC distribution characteristics in both the LT-Ag gene and the coding sequences of its domain regions. In the avian and fish PyVs, the codon diversity was significant, whereas the mammalian PyVs tended to exhibit conservative and host-specific evolution of codon usage bias. The results of our PR2 and neutrality analysis revealed mutation bias or highly variable GC contents by showing a narrow GC12 distribution and wide GC3 distribution in all sequences. Furthermore, the calculated RSCU values revealed differences in the codon usage preference of the LT-AG gene according to the host group. A similar tendency was observed in the two functional domains used in the analysis.

Conclusions

Our study showed that specific domains or sequence motifs of various PyV LT-Ags have evolved so that each virus protein interacts with host cell targets. They have also adapted to thrive in specific host species and cell types. Functional domains of LT-Ag, which are known to interact with host proteins involved in cell proliferation and gene expression regulation, may provide important information, as they are significantly related to the host specificity of PyVs.

Novel Polyomaviruses in Mammals from Multiple Orders and Reassessment of Polyomavirus Evolution and Taxonomy

As the phylogenetic organization of mammalian polyomaviruses is complex and currently incompletely resolved, we aimed at a deeper insight into their evolution by identifying polyomaviruses in host orders and families that have either rarely or not been studied. Sixteen unknown and two known polyomaviruses were identified in animals that belong to 5 orders, 16 genera, and 16 species. From 11 novel polyomaviruses, full genomes could be determined. Splice sites were predicted for large and small T antigen (LTAg, STAg) coding sequences (CDS) and examined experimentally in transfected cell culture. In addition, splice sites of seven published polyomaviruses were analyzed. Based on these data, LTAg and STAg annotations were corrected for 10/86 and 74/86 published polyomaviruses, respectively. For 25 polyomaviruses, a spliced middle T CDS was observed or predicted. Splice sites that likely indicate expression of additional, alternative T antigens, were experimentally detected for six polyomaviruses. In contrast to all other mammalian polyomaviruses, three closely related cetartiodactyl polyomaviruses display two introns within their LTAg CDS. In addition, the VP2 of Glis glis (edible dormouse) polyomavirus 1 was observed to be encoded by a spliced transcript, a unique experimental finding within the Polyomaviridae family. Co-phylogenetic analyses based on LTAg CDS revealed a measurable signal of codivergence when considering all mammalian polyomaviruses, most likely driven by relatively recent codivergence events. Lineage duplication was the only other process whose influence on polyomavirus evolution was unambiguous. Finally, our analyses suggest that an update of the taxonomy of the family is required, including the creation of novel genera of mammalian and non-mammalian polyomaviruses.

Isolation and characterization of an Aves polyomavirus 1 from diseased budgerigars in China

Aves polyomavirus 1 (APV) causes inflammatory disease in psittacine birds, especially in young budgerigar. In this study, an APV virus (SD18 strain) was isolated from a diseased psittacine birds breeding facility. The full genome (4981 bp) of SD18 was determined and analyzed. Phylogenetic analysis of full genome sequences indicated all the APV strains form two groups. The SD18 strain showed close relationship with APV isolated from Poland, however, the other Chinese strains are located in group II, which suggested different genotypes APVs are co-circulating in China. Compared with the consensus sequence of APV full genome, the SD18 strain contains 13 nucleotide mutations, and 2 unique amino acid substitutions (R179M and Q382K) located in VP2/3 and Large T proteins. To explore the pathogenicity of the virus, the SD18 strain was used to challenge 2-week-old budgerigars. All infected birds died no later than 5 days post infection, and virus was detected in multiple organs including brain, heart, ingluvies, liver, and intestine, which indicated that SD18 is fatal and causes systemic infection in young budgerigar. In vitro studies showed that SD18 replicated efficiently in CEF cells and reached the highest viral titers at 9 days post infection. Notably, replication of SD18 stimulated IFN-β response in CEF cells and overexpression of the VP4 or VP4Delta proteins significantly inhibited IFN-β promoter activation, which could be the strategy of APV to escape from the host innate immunity.

Norway and black rats in Europe: potential reservoirs for zoonotic arthropod-borne pathogens?

BACKGROUND

Norway rats (Rattus norvegicus) and black rats (R. rattus) are known to be cosmopolitan reservoirs for zoonotic agents. Nevertheless, little is known about prevalence and distribution of arthropod-borne pathogens in rats from Europe. Therefore, this survey focused on the detection of arthropod-borne pathogens. Spleen-derived DNA samples were available from 528 Norway rats and 74 black rats collected in several European countries. Further, these samples were processed by polymerase chain reaction for the detection of zoonotic pathogens such as Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis (CNM), Babesia spp. and Bartonella spp. eventually followed by sequencing.

RESULTS

Babesia spp. was not detected. Four Norway rat samples were positive for A. phagocytophilum DNA and two for CNM. In 50 rat samples, Bartonella spp. DNA was detected (8.1%; 95% Confidence interval (CI) 6.2-10.61). Whereas B. tribocorum (n = 45) and B. grahamii (n = 1) were carried exclusively in Norway rats from Central Europe (Belgium, Germany), B. coopersplainsensis (n = 4) was detected only in black rats from southern European countries (Spain, Italy).

CONCLUSIONS

Pathogenic Bartonella spp. DNA was found in black and Norway rats from Germany, Italy, Spain and Belgium for the first time. Bartonellae were found focally in zoos suggesting Norway rats as a possible reservoir for B. tribocorum and black rats as a reservoir for B. coopersplainsensis in Europe. These findings should raise awareness of pathogenic Bartonella spp. in Norway rats, especially in terms of pest management control in zoos. Norway and black rats seem not to be predominantly involved in the life cycle of the other examined arthropod-borne pathogens in Europe. © 2019 Society of Chemical Industry.

New polyomavirus species identified in nutria, Myocastor coypus polyomavirus 1

A novel polyomavirus (PyVs) comprising 5,422 bp was identified by high-throughput sequencing (HTS) in pooled organs of nutria (Myocastor coypus). The new genome displays the archetypal organization of PyVs, which includes open reading frames for the regulatory proteins small T antigen (sTAg) and large T antigen (LTAg), as well as for the capsid proteins VP1, VP2 and VP3. Based on the International Committee on Taxonomy of Viruses (ICTV) Polyomaviridae Study Group criteria, this genome comprises a new PyVs species for the Alphapolyomavirus genus and is putatively named "Myocastor coypus Polyomavirus 1" . The complete genome sequence of this Myocastor coypus Polyomavirus 1 (McPyV1) isolate is publically available under the GenBank accession no. MH182627.

Rat polyomavirus 2 infection in a colony of X-linked severe combined immunodeficiency rats in Japan

Polyomaviruses (PyVs) infect a wide range of animals and provoke wasting diseases, particularly in immunosuppressed hosts. Recently, a novel Rattus norvegicus polyomavirus 2 (RatPyV2) has been identified in a colony of X-linked severe combined immunodeficiency (X-SCID) rats in the United States. Here, we describe the first report of the RatPyV2 infection in an X-SCID rat colony in Japan. The affected rats exhibited adult-onset wasting. Histologically, we observed large basophilic intranuclear inclusion bodies within the hyperplastic or dysplastic epithelial cells in the salivary glands, Harderian glands, extraorbital lacrimal glands, and in respiratory and reproductive tissues. Among these organs, the parotid salivary, Harderian, and extraorbital lacrimal glands were most obviously affected. In particular, the parotid salivary glands were the most severely and diffusely affected and atrophic lesions were prominent even at 1 month of age, which suggested that the parotid salivary glands would be highly susceptible to RatPyV2 in X-SCID rats. RatPyV2 inclusion bodies were also detected in the tail of the epididymis and deferent duct. Such reproductive lesions developed significantly in the later stage of breeding age, and therefore may be associated with the reduced fecundity observed in the infected X-SCID rats. We also established a simple, rapid, and non-invasive diagnostic method based on the Amp-FTA method, using buccal swabs for the detection of RatPyV2 in immunodeficient rats. Our findings contribute to the early detection and diagnosis of RatPyV2 infections.

Merkel Cell Polyomavirus Infection of Animal Dermal Fibroblasts

Merkel cell polyomavirus (MCPyV) is the first polyomavirus to be associated with human cancer. Mechanistic studies attempting to fully elucidate MCPyV's oncogenic mechanisms have been hampered by the lack of animal models for MCPyV infection. In this study, we examined the ability of MCPyV-GFP pseudovirus (containing a green fluorescent protein [GFP] reporter construct), MCPyV recombinant virions, and several MCPyV chimeric viruses to infect dermal fibroblasts isolated from various model animals, including mouse (Mus musculus), rabbit (Oryctolagus cuniculus), rat (Rattus norvegicus), chimpanzee (Pan troglodytes), rhesus macaque (Macaca mulatta), patas monkey (Erythrocebus patas), common woolly monkey (Lagothrix lagotricha), red-chested mustached tamarin (Saguinus labiatus), and tree shrew (Tupaia belangeri). We found that MCPyV-GFP pseudovirus was able to enter the dermal fibroblasts of all species tested. Chimpanzee dermal fibroblasts were the only type that supported vigorous MCPyV gene expression and viral replication, and they did so to a level beyond that of human dermal fibroblasts. We further demonstrated that both human and chimpanzee dermal fibroblasts produce infectious MCPyV virions that can successfully infect new cells. In addition, rat dermal fibroblasts supported robust MCPyV large T antigen expression after infection with an MCPyV chimeric virus in which the entire enhancer region of the MCPyV early promoter has been replaced with the simian virus 40 (SV40) analog. Our results suggest that viral transcription and/or replication events represent the major hurdle for MCPyV cross-species transmission. The capacity of rat dermal fibroblasts to support MCPyV early gene expression suggests that the rat is a candidate model organism for studying viral oncogene function during Merkel cell carcinoma (MCC) oncogenic progression.IMPORTANCE MCPyV plays an important role in the development of a highly aggressive form of skin cancer, Merkel cell carcinoma (MCC). With the increasing number of MCC diagnoses, there is a need to better understand the virus and its oncogenic potential. However, studies attempting to fully elucidate MCPyV's oncogenic mechanisms have been hampered by the lack of animal models for MCPyV infection. To pinpoint the best candidate for developing an MCPyV infection animal model, we examined MCPyV's ability to infect dermal fibroblasts isolated from various established model animals. Of the animal cell types we tested, chimpanzee dermal fibroblasts were the only isolates that supported the full MCPyV infectious cycle. To overcome the infection blockade in the other model animals, we constructed chimeric viruses that achieved robust MCPyV entry and oncogene expression in rat fibroblasts. Our results suggest that the rat may serve as an in vivo model to study MCV oncogenesis.

Novel polyomaviruses in shrews (Soricidae) with close similarity to human polyomavirus 12

Shrews (family Soricidae) have already been reported to host microorganisms pathogenic for humans. In an effort to search for additional infectious agents with zoonotic potential, we detected polyomaviruses (PyVs) in common shrew, crowned shrew, and pygmy shrew (Sorex araneus, S. coronatus and S. minutus). From these, 11 full circular genomes were determined. Phylogenetic analysis based on large T protein sequences showed that these novel PyVs form a separate clade within the genus Alphapolyomavirus. Within this clade, the phylogenetic relationships suggest host-virus co-divergence. Surprisingly, one PyV from common shrew showed a genomic sequence nearly identical to that of the human polyomavirus 12 (HPyV12). This indicated that HPyV12 is a variant of a non-human PyV that naturally infects shrews. Whether HPyV12 is a bona fide human-tropic polyomavirus arising from a recent shrew-to-human transmission event or instead reflects a technical artefact, such as consumable contamination with shrew material, needs further investigation.

Assessing the Diversity of Rodent-Borne Viruses: Exploring of High-Throughput Sequencing and Classical Amplification/Sequencing Approaches

Rodents are distributed throughout the world and interact with humans in many ways. They provide vital ecosystem services, some species are useful models in biomedical research and some are held as pet animals. However, many rodent species can have adverse effects such as damage to crops and stored produce, and they are of health concern because of the transmission of pathogens to humans and livestock. The first rodent viruses were discovered by isolation approaches and resulted in break-through knowledge in immunology, molecular and cell biology, and cancer research. In addition to rodent-specific viruses, rodent-borne viruses are causing a large number of zoonotic diseases. Most prominent examples are reemerging outbreaks of human hemorrhagic fever disease cases caused by arena- and hantaviruses. In addition, rodents are reservoirs for vector-borne pathogens, such as tick-borne encephalitis virus and Borrelia spp., and may carry human pathogenic agents, but likely are not involved in their transmission to human. In our days, next-generation sequencing or high-throughput sequencing (HTS) is revolutionizing the speed of the discovery of novel viruses, but other molecular approaches, such as generic RT-PCR/PCR and rolling circle amplification techniques, contribute significantly to the rapidly ongoing process. However, the current knowledge still represents only the tip of the iceberg, when comparing the known human viruses to those known for rodents, the mammalian taxon with the largest species number. The diagnostic potential of HTS-based metagenomic approaches is illustrated by their use in the discovery and complete genome determination of novel borna- and adenoviruses as causative disease agents in squirrels. In conclusion, HTS, in combination with conventional RT-PCR/PCR-based approaches, resulted in a drastically increased knowledge of the diversity of rodent viruses. Future improvements of the used workflows, including bioinformatics analysis, will further enhance our knowledge and preparedness in case of the emergence of novel viruses. Classical virological and additional molecular approaches are needed for genome annotation and functional characterization of novel viruses, discovered by these technologies, and evaluation of their zoonotic potential.

A Naturally Transmitted Epitheliotropic Polyomavirus Pathogenic in Immunodeficient Rats: Characterization, Transmission, and Preliminary Epidemiologic Studies

We report the identification, pathogenesis, and transmission of a novel polyomavirus in severe combined immunodeficient F344 rats with null Prkdc and interleukin 2 receptor gamma genes. Infected rats experienced weight loss, decreased fecundity, and mortality. Large basophilic intranuclear inclusions were observed in epithelium of the respiratory tract, salivary and lacrimal glands, uterus, and prostate gland. Unbiased viral metagenomic sequencing of lesioned tissues identified a novel polyomavirus, provisionally named Rattus norvegicus polyomavirus 2 (RatPyV2), which clustered with Washington University (WU) polyomavirus in the Wuki clade of the Betapolyomavirus genus. In situ hybridization analyses and quantitative polymerase chain reaction (PCR) results demonstrated viral nucleic acids in epithelium of respiratory, glandular, and reproductive tissues. Polyomaviral disease was reproduced in Foxn1^rnu nude rats cohoused with infected rats or experimentally inoculated with virus. After development of RatPyV2-specific diagnostic assays, a survey of immune-competent rats from North American research institutions revealed detection of RatPyV2 in 7 of 1,000 fecal samples by PCR and anti-RatPyV2 antibodies in 480 of 1,500 serum samples. These findings suggest widespread infection in laboratory rat populations, which may have profound implications for established models of respiratory injury. Additionally, RatPyV2 infection studies may provide an important system to investigate the pathogenesis of WU polyomavirus diseases of man.

Polyomavirus-associated Prostatitis in Wistar Han Rats Following Immunosuppression in a Chronic Toxicity Study

Chronic prostatitis characterized on light microscopic examination by moderate, multifocal, predominantly lymphocytic inflammation associated with epithelial atypia and intranuclear and cytoplasmic inclusion-like material was identified in the prostate gland of 2 Wistar Han rats administered an immunomodulatory test article in a 6-month chronic toxicity study. Transmission electron microscopy of the prostate glands identified 45-nm, nonenveloped, icosahedral virions arranged in paracrystalline array within the cell nuclei in 1 of the 2 rats. The size, shape, location, and array pattern were most consistent with a polyomavirus. The light and electron microscopic findings after immunosuppression in our case have a resemblance to a polyomavirus recently reported to affect prostate gland epithelium in a colony of immunocompromised X-linked severe combined immune deficiency rats. To the best of our knowledge, this is the first report of light and electronic microscopic lesions in the reproductive tract associated with polyomavirus following chronic immunosuppression in a widely used, wild-type Wistar Han rat.

Survey for zoonotic pathogens in Norway rat populations from Europe

BACKGROUND

The Norway rat Rattus norvegicus is an important reservoir of various zoonotic pathogens, such as cowpox virus and Leptospira, but also for agents of no or unknown zoonotic potential. We describe a survey of 426 Norway rats originating from five European countries and different habitats for Leptospira spp., rickettsiae, orthopoxvirus (OPV), avian metapneumovirus subtypes A and B (aMPV) and rat polyomavirus (rat PyV).

RESULTS

Leptospira DNA was detected in 60 out of 420 (14.3%) rats, and Rickettsia DNA was found in three out of 369 (0.8%) rats investigated. PCR-based typing resulted in the identification of L. interrogans sequence type 17, which corresponds to the serogroup Icterohaemorrhagiae, and Rickettsia helvetica respectively. Rat PyV DNA was detected in 103 out of 421 (24.5%) rats. OPV DNA and aMPV RNA were detected in none of the rats, but OPV-specific antibodies were detected in three out of 388 (0.8%) rats. The frequency of single Leptospira and rat PyV infections and coinfections was, independent of sex, greater for adults compared with juveniles/subadults and greater at rural sites compared with urban areas.

CONCLUSIONS

Study results indicate a broad geographical distribution of Leptospira DNA in rats within Europe, underlining the need to investigate further the potential mechanisms leading to increased prevalence in rural habitats and to assess the relevance to public health. In contrast, rickettsia and OPV infections rarely occurred in wild rat populations. The potential influence of rat PyV on the susceptibility to infections with other pathogens should be investigated in future studies. © 2016 Society of Chemical Industry.

Identification and Characterization of Novel Rat Polyomavirus 2 in a Colony of X-SCID Rats by P-PIT assay

Although P-PIT was developed to detect diseases associated with known human polyomaviruses, the identification of a new polyomavirus in rats suggests that it may have utility as a broad-based screen for new, as well as known polyomaviruses. Our findings suggest that RatPyV2 may be a commensal infection of laboratory rats that can lead to disseminated disease in T cell immune-deficient rats. Infection of the X-SCID rats with RatPyV2 and Pneumocystis carinii is a potential model for coinfection pathogenesis and treatment options during transplant preclinical studies.

Polyomaviruses (PyVs) are known to infect a wide range of vertebrates and invertebrates and are associated with a broad spectrum of diseases, including cancers, particularly in immune-suppressed hosts. A novel polyomavirus, designated rat polyomavirus 2 (RatPyV2), was identified from a breeding colony of rats having X-linked severe combined immunodeficiency. Using a human panpolyomavirus immunohistochemistry test (P-PIT), RatPyV2 was initially detected in the parotid salivary gland of a colony member. Rolling circle amplification using DNA from harderian and parotid glands identified a novel 5.1-kb polyomavirus genome closely related to human Washington University (WU) and Karolinska Institute (KI) and vole polyomaviruses but notably divergent from Rattus norvegicus PyV1 (RnorPyV1; also designated RatPyV1). Further screening showed RatPyV2 inclusion body infection in the lung epithelium and variably in other respiratory, reproductive, and glandular tissues of 12/12 (100%) rats.

IMPORTANCE Although P-PIT was developed to detect diseases associated with known human polyomaviruses, the identification of a new polyomavirus in rats suggests that it may have utility as a broad-based screen for new, as well as known polyomaviruses. Our findings suggest that RatPyV2 may be a commensal infection of laboratory rats that can lead to disseminated disease in T cell immune-deficient rats. Infection of the X-SCID rats with RatPyV2 and Pneumocystis carinii is a potential model for coinfection pathogenesis and treatment options during transplant preclinical studies.

Genome Sequences of Polyomaviruses from the Wild-Living Red Colobus (Piliocolobus badius) and Western Chimpanzee (Pan troglodytes verus)

We identified with PCR and sequencing the full genomes of the recently discovered Pan troglodytes verus polyomavirus 8 and Piliocolobus badius polyomavirus 2 in a western chimpanzee and a western red colobus free-ranging in Taï National Park of Côte d’Ivoire.