Identification and characterization of a new bocavirus species in gorillas

Novel viruses discovered in metatranscriptomic analysis of farmed barramundi in Asia and Australia

Barramundi aquaculture is at risk of severe disease outbreaks and massive production losses. Here we used bioinformatics to screen 84 farmed barramundi transcriptomes to identify novel viruses that could threaten barramundi aquaculture and to establish a barramundi aquaculture virome. We discovered five novel viruses: latid herpesvirus 1 (LatHV-1) from the Alloherpesviridae family, barramundi parvovirus 1 (BParV1) from the Parvoviridae family, barramundi calicivirus 1 (BCaV1) from the Caliciviridae family, and barramundi associated picorna-like virus 1 and 2 (BPicV1 and BPicV2) from the Picornaviridae family. LatHV-1, BCaV1, and BParV1 are closely related to pathogenic viruses found in other fish species that can cause mass mortality in farms. To aid in future viral surveillance, we also designed and successfully tested an RT-PCR assay for the detection of BCaV1. Overall, we discovered a range of pathogenic viruses in barramundi aquaculture, paving the way for developing effective detection methods to assist early outbreak management.

Epidemiology and genetic diversity of bocavirus in wild rodents in urban areas of Guangzhou, Southern China

Members of the genus Bocaparvovirus have a significant impact on human health and can infect a wide range of hosts, increasing the likelihood of crossing species barriers. Among the various mammalian hosts, rodents are widely recognized as important reservoirs for emerging and zoonotic viruses. However, despite recent reports of bocavirus infections in rodents, our current understanding of rat bocavirus (RBoV) genetic diversity and evolution is limited. In this study, rodent samples were collected from the urban areas of Guangzhou city, Southern China, to investigate the presence and genetic diversity of RBoV. Through PCR-based screening of 296 rodent spleens, 54 samples were determined to be positive for RBoV infection, and 12 nearly complete genome sequences of RBoV were recovered. Phylogenetic analysis revealed distinct lineages and sub-lineages of RBoV, and six recombination events with strong statistical support were identified, with five of these events involving sequences obtained from this study. These results highlight the genetic diversity of RBoV circulating in rodents in Guangzhou city and emphasize the importance of extensive surveillance to gain a better understanding of RBoV epidemiology, evolutionary characteristics, and potential for cross-species transmission.

Epidemiology and genotypic diversity of feline bocavirus identified from cats in Harbin, China

Feline bocavirus (FBoV) is a globally distributed linear, single-stranded DNA virus infect cats, currently classified into three distinct genotypes. Although FBoV can lead to systemic infections, its complete pathogenic potential remains unclear. In this study, 289 blood samples were collected from healthy cats in Harbin, revealing an overall FBoV prevalence of 12.1%. Notably, genotypes 1 and 3 of FBoV were found co-circulating among the cat population in Harbin. Additionally, recombination events were detected, particularly in the newly discovered NG/104 and DL/102 strains. Furthermore, negative selection sites were predominantly observed across the protein coding genes of FBoV. These findings suggest a co-circulation of genetically diverse FBoV strains among cats in Harbin, indicate that purifying selection is the primary driving force shaping the genomic evolution of FBoV, and also underscore the importance of comprehensive surveillance efforts to enhance our understanding of the epidemiology and evolutionary characteristics of FBoV.

Virome characterization and identification of a putative parvovirus and poxvirus in bat ectoparasites of Yunnan Province, China

Ectoparasites found on bats are known to contain important microbes. However, the viruses hosted by these obligate parasites are understudied. This has led to the near oversight of the potential role of these ectoparasites in virus maintenance and transmission from bats to other interacting species and the environment. Here, we sampled bat ectoparasites parasitizing a diverse selection of bat species in the families Rhinolophidae, Vespertilionidae, Megadermatidae, Hipposideridae and Pteropodidae in Yunnan Province, China. We show that the ectoparasite prevalence was generally higher in male compared to female bats. Most ectoparasites were found to fall within the Nycteribiidae, Spinturnicidae and Streblidae bat ectoparasite families. We subsequently applied a non-biased sequencing of libraries prepared from the pooled ectoparasites, followed by an in-silico virus-centric analysis of the resultant reads. We show that ectoparasites hosted by the sampled families of bats are found to carry, in addition to a diverse set of phages, vertebrate and insect viruses in the families Aliusviridae, Ascoviridae, Chuviridae, Circoviridae, Flaviviridae, Hepadnaviridae, Hepeviridae, Herpesviridae, Iridoviridae, Marseilleviridae, Nairoviridae, Orthomyxoviridae, Parvoviridae, Poxviridae, Reoviridae, Retroviridae, and Rhabdoviridae. We further report a partial Parvovirus VP1/VP2 gene and partial Poxvirus ubiquitin-like gene predicted by two independent next generation sequencing data analysis pipelines. This study describes the natural virome of bat ectoparasites, providing a platform for understanding the role these ectoparasites play in the maintenance and spread of viruses to other animals.

Old and Novel Enteric Parvoviruses of Dogs

Parvovirus infections have been well known for around 100 years in domestic carnivores. However, the use of molecular assays and metagenomic approaches for virus discovery and characterization has led to the detection of novel parvovirus species and/or variants in dogs. Although some evidence suggests that these emerging canine parvoviruses may act as primary causative agents or as synergistic pathogens in the diseases of domestic carnivores, several aspects regarding epidemiology and virus-host interaction remain to be elucidated.

Novel Virus Identification through Metagenomics: A Systematic Review

Metagenomic Next Generation Sequencing (mNGS) allows the evaluation of complex microbial communities, avoiding isolation and cultivation of each microbial species, and does not require prior knowledge of the microbial sequences present in the sample. Applications of mNGS include virome characterization, new virus discovery and full-length viral genome reconstruction, either from virus preparations enriched in culture or directly from clinical and environmental specimens. Here, we systematically reviewed studies that describe novel virus identification through mNGS from samples of different origin (plant, animal and environment). Without imposing time limits to the search, 379 publications were identified that met the search parameters. Sample types, geographical origin, enrichment and nucleic acid extraction methods, sequencing platforms, bioinformatic analytical steps and identified viral families were described. The review highlights mNGS as a feasible method for novel virus discovery from samples of different origins, describes which kind of heterogeneous experimental and analytical protocols are currently used and provides useful information such as the different commercial kits used for the purification of nucleic acids and bioinformatics analytical pipelines.

Diversity of CRESS DNA Viruses in Squamates Recapitulates Hosts Dietary and Environmental Sources of Exposure

Replication-associated protein (Rep)-encoding single-stranded (CRESS) DNA viruses comprise viruses with covalently closed, circular, single-stranded DNA (ssDNA) genomes, and are considered the smallest known autonomously replicating, capsid-encoding animal pathogens. CRESS DNA viruses (phylum Cressdnaviricota) encompass several viral families including Circoviridae. Circoviruses are classified into two genera, Circovirus and Cyclovirus, and they are known to cause fatal diseases in birds and pigs. Circoviruses have also been identified in human stools, blood, and cerebrospinal fluid (CSF), as well as in various wild and domestic vertebrates, including reptiles. The synanthropic presence of Squamata reptiles has increased in the last century due to the anthropic pressure, which has shifted forested animal behavior to an urban and peri-urban adaptation. In this paper, we explored the diversity of CRESS DNA viruses in Squamata reptiles from different Italian areas representative of the Mediterranean basin. CRESS DNA viruses were detected in 31.7% (33/104) of sampled lizards and geckoes. Different CRESS DNA viruses likely reflected dietary composition or environmental contamination and included avian-like (n = 3), dog (n = 4), bat-like (n = 1), goat-like (n = 1), rodent-like (n = 4), and insect-like (n = 2) viruses. Rep sequences of at least two types of human-associated cycloviruses (CyV) were identified consistently, regardless of geographic location, namely, TN9-like (n = 11) and TN12-like (n = 6). A third human-associated CyV, TN25-like, was detected in a single sample. The complete genome of human-like CyVs, of a rodent-like, insect-like, and of a bat-like virus were generated. Collectively, the results recapitulate hosts dietary and environmental sources of exposure and may suggest unexpected ecological niches for some CRESS DNA viruses.

IMPORTANCE CRESS DNA viruses are significant pathogens of birds and pigs and have been detected repeatedly in human samples (stools, serum, and cerebrospinal fluid), both from healthy individuals and from patients with neurological disease, eliciting in 2013 a risk assessment by the European Centre for Disease Prevention and Control (ECDC). Sequences of CRESS DNA viruses previously reported in humans (TN9, TN12, and TN25), and detected in different animal species (e.g., birds, dogs, and bats) were herein detected in fecal samples of synanthropic squamates (geckos and lizards). The complete genome sequence of six viruses was generated. This study extends the information on the genetic diversity and ecology of CRESS DNA viruses. Because geckos and lizards are synanthropic animals, a role in sustaining CRESS DNA virus circulation and increasing viral pressure in the environment is postulated.

Correlation between Metabolic Rate and Salinity Tolerance and Metabolic Response to Salinity in Grass Carp (Ctenopharyngodon idella)

Simple Summary

The association between the metabolic rate and salinity tolerance in stenohaline freshwater fish could affect how fish adapt to changes in environmental salinity. In Experiment I, the metabolic rates and upper salinity tolerance limit of the grass carp were determined individually, and we aimed to test whether an association existed between the salinity tolerance capacity and both the resting metabolic rate and maximum metabolic rate. In Experiment II, the effects of increasing salinity on metabolic rates, gill histology, and Na⁺-K⁺-ATPase activities were determined in grass carp. The results suggest that a lower metabolic rate may not necessarily allow for a better salinity tolerance capacity of grass carp. Salinity-induced changes in the gill surface contribute more to ion exchange capacity than to oxygen uptake capacity.

Abstract

The metabolic rate could be one of the factors affecting the salinity tolerance capacity of fish. Experiment I tested whether metabolic rates correlate with the upper salinity tolerance limit among individual grass carp by daily increasing salinity (1 g kg⁻¹ day⁻¹). The feeding dropped sharply as the salinity reached 10 g kg⁻¹ and ceased when salinities exceeded 11 g kg⁻¹. The ventilation frequency decreased weakly as salinity increased from 0 to 12 g kg⁻¹ and then increased rapidly as salinity reached 14 g kg⁻¹. The fish survived at salinities lower than 14 g kg⁻¹, and all fish died when salinity reached 17 g kg⁻¹. The upper salinity tolerance limit was not correlated with metabolic rates. Therefore, a lower metabolic rate may not necessarily allow for better salinity tolerance capacity. Experiment II tested how different salinities (0, 0.375, 0.75, 1.5, 3, and 6 g kg⁻¹ for 2 weeks) affect the metabolic parameters of grass carp. The changes in the resting metabolic rate with increasing salinity could be explained by the relative changes in interlamellar cell mass and protruding lamellae. The maximum metabolic rate remained constant, suggesting that the salinity-induced changes in the gill surface had a minor effect on oxygen uptake capacity.

Best of most possible worlds: Hybrid gene therapy vectors based on parvoviruses and heterologous viruses

Parvoviruses and especially the adeno-associated virus (AAV) species provide an exciting and versatile platform for the rational design or molecular evolution of human gene-therapy vectors, documented by literature from over half a century, hundreds of clinical trials, and the recent commercialization of multiple AAV gene therapeutics. For the last three decades, the power of these vectors has been further potentiated through various types of hybrid vectors created by intra- or inter-genus juxtaposition of viral DNA and protein cis elements or by synergistic complementation of parvoviral features with those of heterologous, prokaryotic, or eukaryotic viruses. Here, we provide an overview of the history and promise of this rapidly expanding field of hybrid parvoviral gene-therapy vectors, starting with early generations of chimeric particles composed of a recombinant AAV genome encapsidated in shells of synthetic AAVs or of adeno-, herpes-, baculo-, or protoparvoviruses. We then dedicate our attention to two newer, highly promising types of hybrid vectors created via (1) pseudotyping of AAV genomes with bocaviral serotypes and capsid mutants or (2) packaging of AAV DNA into, or tethering of entire vector particles to, bacteriophages. Finally, we conclude with an outlook summarizing critical requirements and improvements toward clinical translation of these original concepts.

Small but mighty: old and new parvoviruses of veterinary significance

In line with the Latin expression "sed parva forti" meaning "small but mighty," the family Parvoviridae contains many of the smallest known viruses, some of which result in fatal or debilitating infections. In recent years, advances in metagenomic viral discovery techniques have dramatically increased the identification of novel parvoviruses in both diseased and healthy individuals. While some of these discoveries have solved etiologic mysteries of well-described diseases in animals, many of the newly discovered parvoviruses appear to cause mild or no disease, or disease associations remain to be established. With the increased use of animal parvoviruses as vectors for gene therapy and oncolytic treatments in humans, it becomes all the more important to understand the diversity, pathogenic potential, and evolution of this diverse family of viruses. In this review, we discuss parvoviruses infecting vertebrate animals, with a special focus on pathogens of veterinary significance and viruses discovered within the last four years.

Human bocavirus 2 detected in Rattus norvegicus feces in China

Bocaviruses are typical zoonotic pathogens with a wide range of hosts. Here, we report the detection of human bocavirus (HBoV) in Rattus norvegicus captured in China and the results of sequencing and phylogenetic analysis based on the partial VP1 region and the entire viral genome. A total of 357 fecal samples from rats were collected in 2015-2017 and analyzed for HBoV using PCR. The detection rate of HBoV was 0.84% (3/357). Phylogenetic analysis revealed that this virus is genetically closely related to HBoV-2. R. norvegicus may be a carrier of HBoV, and its impact on public health merits attention.

Recent Advances in Molecular Biology of Human Bocavirus 1 and Its Applications

Human bocavirus 1 (HBoV1) was discovered in human nasopharyngeal specimens in 2005. It is an autonomous human parvovirus and causes acute respiratory tract infections in young children. HBoV1 infects well differentiated or polarized human airway epithelial cells in vitro. Unique among all parvoviruses, HBoV1 expresses 6 non-structural proteins, NS1, NS1-70, NS2, NS3, NS4, and NP1, and a viral non-coding RNA (BocaSR), and three structural proteins VP1, VP2, and VP3. The BocaSR is the first identified RNA polymerase III (Pol III) transcribed viral non-coding RNA in small DNA viruses. It plays an important role in regulation of viral gene expression and a direct role in viral DNA replication in the nucleus. HBoV1 genome replication in the polarized/non-dividing airway epithelial cells depends on the DNA damage and DNA repair pathways and involves error-free Y-family DNA repair DNA polymerase (Pol) η and Pol κ. Importantly, HBoV1 is a helper virus for the replication of dependoparvovirus, adeno-associated virus (AAV), in polarized human airway epithelial cells, and HBoV1 gene products support wild-type AAV replication and recombinant AAV (rAAV) production in human embryonic kidney (HEK) 293 cells. More importantly, the HBoV1 capsid is able to pseudopackage an rAAV2 or rHBoV1 genome, producing the rAAV2/HBoV1 or rHBoV1 vector. The HBoV1 capsid based rAAV vector has a high tropism for human airway epithelia. A deeper understanding in HBoV1 replication and gene expression will help find a better way to produce the rAAV vector and to increase the efficacy of gene delivery using the rAAV2/HBoV1 or rHBoV1 vector, in particular, to human airways. This review summarizes the recent advances in gene expression and replication of HBoV1, as well as the use of HBoV1 as a parvoviral vector for gene delivery.

Emerging Parvoviruses in Domestic Cats

Parvovirus infections in cats have been well known for around 100 years. Recently, the use of molecular assays and metagenomic approaches for virus discovery and characterization has led to the detection of novel parvovirus lineages and/or species infecting the feline host. However, the involvement of emerging parvoviruses in the onset of gastroenteritis or other feline diseases is still uncertain.

Characterization of the GBoV1 Capsid and Its Antibody Interactions

Human bocavirus 1 (HBoV1) has gained attention as a gene delivery vector with its ability to infect polarized human airway epithelia and 5.5 kb genome packaging capacity. Gorilla bocavirus 1 (GBoV1) VP3 shares 86% amino acid sequence identity with HBoV1 but has better transduction efficiency in several human cell types. Here, we report the capsid structure of GBoV1 determined to 2.76 Å resolution using cryo-electron microscopy (cryo-EM) and its interaction with mouse monoclonal antibodies (mAbs) and human sera. GBoV1 shares capsid surface morphologies with other parvoviruses, with a channel at the 5-fold symmetry axis, protrusions surrounding the 3-fold axis and a depression at the 2-fold axis. A 2/5-fold wall separates the 2-fold and 5-fold axes. Compared to HBoV1, differences are localized to the 3-fold protrusions. Consistently, native dot immunoblots and cryo-EM showed cross-reactivity and binding, respectively, by a 5-fold targeted HBoV1 mAb, 15C6. Surprisingly, recognition was observed for one out of three 3-fold targeted mAbs, 12C1, indicating some structural similarity at this region. In addition, GBoV1, tested against 40 human sera, showed the similar rates of seropositivity as HBoV1. Immunogenic reactivity against parvoviral vectors is a significant barrier to efficient gene delivery. This study is a step towards optimizing bocaparvovirus vectors with antibody escape properties.

Development of SYBR Green I-based polymerase chain reaction for feline bocavirus 1 detection

Feline bocavirus 1 (FBoV-1) may be associated with diarrhea in cats. In this study, a SYBR Green I-based quantitative polymerase chain reaction (qPCR) assay was established to detect FBoV-1. The melting curve showed a single melting peak at 83.0 ℃. The results of sensitivity showed that the detection limit of the qPCR was 3.87 × 10¹ copies/μL. Of note, the detection limit of the conventional polymerase chain reaction (cPCR) was 3.87 × 10³ copies/μL. The highest intra-assay and inter-assay coefficients of variation (CV%) were 0.98% and 1.42%, respectively. The positive detection rate of 128 clinical samples using the qPCR and the cPCR was 7.0% (9/128) and 4.7% (6/128), respectively. Taken together, these results indicated that the established qPCR assay has good sensitivity, high specificity, and good reproducibility. Therefore, it could provide support for the rapid and efficient clinical detection of FBoV-1.

Computational genomics of Torque teno sus virus and Porcine circovirus in swine samples from Canada

Emerging viral diseases include pathogens that can threaten the health of the Canadian swineherd. Anelloviruses and Circoviruses comprise of pathogens with veterinary significance. The aim of this study was to determine the genomic organization and phylogenetic relationships of Torque teno sus virus (TTsusV) and Porcine circovirus (PCV) from Canadian pig samples. Fecal and tissue specimens were collected during the winter, spring and summer of 2018. We utilized either virus- or genus-specific PCR assays to characterize the occurrence and genetic diversity of TTsusV and PCV in Canadian pigs. Pairwise comparison of all partial sequences and identity calculation was performed using MAFFT algorithm implemented in Sequence Demarcation Tool (SDT). The obtained full-length sequences were aligned using ClustalW, and phylogeny was inferred using a Maximum likelihood (ML) method by Geneious software. The PCR detection results revealed that the overall positive rate of TTsusV type-1 and type-2 was 45.6% and 32.6%, respectively. The TTsusV isolate MK990454 from Canada clustered in the subtype TTsusV1b, while the TTsusV isolate MK872392 fell in the subtype TTsusV2c, and all showed similarity to known American and Chinese isolates. In addition, our screening PCR showed that 2.7% of stool samples were positive for PCV1. Phylogenetic analysis using the full-length sequence demonstrated that PCV1 (MK872393) isolated from Quebec clustered with other Chinese PCV1 strains. Despite the far geographical distance between Canada and China, the close similarity between Canadian and Chinese TTsusV1 and 2, and PCV1 sequences may be explained by a considerable amount of pig trade between these two nations.

Human Bocavirus infection and respiratory tract disease identified in a UK patient cohort

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Human Bocavirus 1 (HBoV1) was commonly detected in a survey of circa 13,000 UK respiratory samples between 2015 and 2019.

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Co-infection with other viruses was observed in approximately three quarters of samples.

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However, mono-infection was also prevalent, and associated with clinically relevant disease.

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Intensive care was required in 31% of HBoV1 mono-infections and ventilation in 17%.

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Fatal multi-organ failure was observed in an apparently HBoV1 mono-infected and otherwise healthy child.

Background

Since its first isolation in 2005, Human Bocavirus (HBoV) has been repeatedly associated with acute respiratory tract infections, although its role in pathogenicity remains unclear due to high co-infection rates.

Objectives

To assess HBoV prevalence and associated disease in a cohort of respiratory patients in the East Midlands, UK between 2015 and 2019.

Study design

We initially investigated the undiagnosed burden of HBoV in a retrospective paediatric cohort sampled between 2015 and 2017 using an in-house PCR assay. HBoV was subsequently incorporated into the standard respiratory diagnostic pathway and we audited a calendar year of HBoV positive results between 2018 and 2019.

Results

Our retrospective PCR screening of previously routine diagnostic-negative samples from juvenile patients identified a 9% (n = 30) prevalence of HBoV type 1. These apparent HBoV1 mono-infections were frequently associated with respiratory tract symptoms, often severe requiring ventilation, oxygen and steroid intervention with 31% (n = 9) of individuals requiring intensive care. When HBoV screening was subsequently adopted into the routine respiratory diagnostic pathway, year-round infections were observed in both children and adults peaking in February. 185 of 9098 (2.03%) individuals were found to be HBoV positive with children aged 12–24 months the principally infected group. However, HBoV infection was also observed in patients aged over 60, predominantly as a mono-infection. 23% of the 185 unique patients were HBoV monoinfected and persistent low-level DNA positivity was observed in 15 individuals up to 6-months after initial presentation.

Conclusion

HBoV1 is a prevalent respiratory infection in the UK capable of causing serious monoinfections.

Impact of Natural or Synthetic Singletons in the Capsid of Human Bocavirus 1 on Particle Infectivity and Immunoreactivity

Human bocavirus 1 (HBoV1) is a parvovirus that gathers increasing attention due to its pleiotropic role as a pathogen and emerging vector for human gene therapy. Curiously, albeit a large variety of HBoV1 capsid variants has been isolated from human samples, only one has been studied as a gene transfer vector to date. Here, we analyzed a cohort of HBoV1-positive samples and managed to PCR amplify and sequence 29 distinct HBoV1 capsid variants. These differed from the originally reported HBoV1 reference strain in 32 nucleotides or four amino acids, including a frequent change of threonine to serine at position 590. Interestingly, this T590S mutation was associated with lower viral loads in infected patients. Analysis of the time course of infection in two patients for up to 15 weeks revealed a gradual accumulation of T590S, concurrent with drops in viral loads. Surprisingly, in a recombinant vector context, T590S was beneficial and significantly increased titers compared to that of T590 variants but had no major impact on their transduction ability or immunoreactivity. Additional targeted mutations in the HBoV1 capsid identified several residues that are critical for transduction, capsid assembly, or DNA packaging. Our new findings on the phylogeny, infectivity, and immunoreactivity of HBoV1 capsid variants improve our understanding of bocaviral biology and suggest strategies to enhance HBoV1 gene transfer vectors.IMPORTANCE The family of Parvoviridae comprises a wide variety of members that exhibit a unique biology and that are concurrently highly interesting as a scaffold for the development of human gene therapy vectors. A most notable example is human bocavirus 1 (HBoV1), which we and others have recently harnessed to cross-package and deliver recombinant genomes derived from another parvovirus, the adeno-associated virus (AAV). Here, we expanded the repertoire of known HBoV1 variants by cloning 29 distinct HBoV1 capsid sequences from primary human samples and by analyzing their properties as AAV/HBoV1 gene transfer vectors. This led to our discovery of a mutational hot spot at HBoV1 capsid position 590 that accumulated in two patients during natural infection and that lowers viral loads but increases vector yields. Thereby, our study expands our current understanding of HBoV1 biology in infected human subjects and concomitantly provides avenues to improve AAV/HBoV1 gene transfer vectors.

Identification of viral etiology of acute respiratory tract infections in children and adults in Tabanan, Bali, Indonesia

Acute respiratory tract infection (ARTI) is the most common infectious disease in humans worldwide. The morbidity and mortality rates are high, especially in developing countries from Southeast Asia and Africa. While ARTI is commonly associated with viruses, there is limited data on the spectrum of viruses causing ARTI in developing countries, including Indonesia. This study was based on utilizing molecular techniques targeting a panel of 11 endemic and emerging respiratory viral pathogens including zoonotic viruses in a cohort of children and adults presenting at Tabanan General Hospital, Bali, with acute respiratory illness, from January to November 2017. In total, 98 out of 200 samples (49.0 %) tested positive for viruses. Our study confirmed 64.3 % viral etiology in children and 12.2 % in adults. Viruses that were detected were Herpesviridae (15.0 %) followed by enteroviruses (12.0 %), influenza A virus (11.5 %), respiratory syncytial virus (8.0 %), Adenoviridae (6.5 %), human metapneumovirus (3.5 %), Paramyxoviridae (2.0 %), bocavirus (1.0 %) and Coronaviridae (0.5 %). The study sheds light on the viral spectrum of ARTI in children and adults in Tabanan, Bali, Indonesia.

Feline Virome-A Review of Novel Enteric Viruses Detected in Cats

Recent advances in the diagnostic and metagenomic investigations of the feline enteric environment have allowed the identification of several novel viruses that have been associated with gastroenteritis in cats. In the last few years, noroviruses, kobuviruses, and novel parvoviruses have been repetitively detected in diarrheic cats as alone or in mixed infections with other pathogens, raising a number of questions, with particular regards to their pathogenic attitude and clinical impact. In the present article, the current available literature on novel potential feline enteric viruses is reviewed, providing a meaningful update on the etiology, epidemiologic, pathogenetic, clinical, and diagnostic aspects of the infections caused by these pathogens.

Novel Primate Bocaparvovirus Species 3 Identified in Wild Macaca Mulatta in China

Primate bocaparvovirus (BOV) is a possible cause of respiratory disorders and gastroenteritis in humans. However, the diversity and evolution of these viruses remain largely unknown, despite the identification of a growing number of BOVs in non-human primates (NHPs). Here, we report the identification of a novel BOV (provisionally named Macaca mulatta bocaparvovirus [MmBOV]) in the feces of wild Macaca mulatta in China by viral metagenomic analysis. Seven of 400 fecal samples from Macaca mulatta were positive for MmBOV. An almost complete genome sequence of 4,831 nucleotides was obtained, which had genomic organization and protein motifs similar to human bocaviruses (HOBVs), and shared characteristically low G/C content and weak codon usage bias. Sequence analyses of NS1, NP1, and VP1 revealed that MmBOV was most closely related to HBOV4 of Primate bocaparvovirus 2 (approximately 68.4%/70.6%, 73.3%/67.6%, and 70.4%/73.1% nucleotide/amino acid identities, respectively). Additionally, phylogenetic analysis revealed that MmBOV formed an independent peripheral branch, but clustered closely with those of the Primate bocaparvovirus species in the BOV genus (particularly HBOV4). These data strongly suggest that HBOV4 originated from NHP bocaparvoviruses around 200-300 years ago, and that NHPs may act as HBOV reservoirs. Following the International Committee of Taxonomy for Viruses guidelines, we propose MmBOV as a new species (tentatively named Primate bocaparvovirus 3) in the genus Bocaparvovirus, which is the first report of a novel species of primate BOV. Our data facilitate future research on the genetic diversity and evolution of primate bocaparvoviruses and highlight the importance of bocaparvovirus surveys in wild NHPs.

Metagenomic Next-Generation Sequencing Reveal Presence of a Novel Ungulate Bocaparvovirus in Alpacas

Viruses belonging to the genus Bocaparvovirus(BoV) are a genetically diverse group of DNA viruses known to cause respiratory, enteric, and neurological diseases in animals, including humans. An intestinal sample from an alpaca (Vicugnapacos) herd with reoccurring diarrhea and respiratory disease was submitted for next-generation sequencing, revealing the presence of a BoV strain. The alpaca BoV strain (AlBoV) had a 58.58% whole genome nucleotide percent identity to a camel BoV from Dubai, belonging to a tentative ungulate BoV 8 species (UBoV8). Recombination events were lacking with other UBoV strains. The AlBoV genome was comprised of the NS1, NP1, and VP1 proteins. The NS1 protein had the highest amino acid percent identity range (57.89-67.85%) to the members of UBoV8, which was below the 85% cut-off set by the International Committee on Taxonomy of Viruses. The low NS1 amino acid identity suggests that AlBoV is a tentative new species. The whole genome, NS1, NP1, and VP1 phylogenetic trees illustrated distinct branching of AlBoV, sharing a common ancestor with UBoV8. Walker loop and Phospholipase A2 (PLA2) motifs that are vital for virus infectivity were identified in NS1 and VP1 proteins, respectively. Our study reports a novel BoV strain in an alpaca intestinal sample and highlights the need for additional BoV research.

Oxymatrine Inhibits Bocavirus MVC Replication, Reduces Viral Gene Expression and Decreases Apoptosis Induced by Viral Infection

Oxymatrine (OMT), as the main active component of Sophoraflavescens, exhibits a variety of pharmacological properties, including anti-oxidative, anti-inflammatory, anti-tumor, and anti-viral activities, and currently is extensively employed to treat viral hepatitis; however, its effects on parvovirus infection have yet to be reported. In the present study, we investigated the effects of OMT on cell viability, virus DNA replication, viral gene expression, cell cycle, and apoptosis in Walter Reed canine cells/3873D infected with minute virus of canines (MVC). OMT, at concentrations below 4 mmol/L(no cellular toxicity), was found to inhibit MVC DNA replication and reduce viral gene expression at both mRNA and protein levels, which was associated with the inhibition of cell cycle S-phase arrest in early-stage of MVC infection. Furthermore, OMT significantly increased cell viability, decreased MVC-infected cell apoptosis, and reduced the expression of activated caspase 3. Our results suggest that OMT has potential application in combating parvovirus infection.

Novel Chimeric Gene Therapy Vectors Based on Adeno-Associated Virus and Four Different Mammalian Bocaviruses

Parvoviruses are highly attractive templates for the engineering of safe, efficient, and specific gene therapy vectors, as best exemplified by adeno-associated virus (AAV). Another candidate that currently garners increasing attention is human bocavirus 1 (HBoV1). Notably, HBoV1 capsids can cross-package recombinant (r)AAV2 genomes, yielding rAAV2/HBoV1 chimeras that specifically transduce polarized human airway epithelia (pHAEs). Here, we largely expanded the repertoire of rAAV/BoV chimeras, by assembling packaging plasmids encoding the capsid genes of four additional primate bocaviruses, HBoV2–4 and GBoV (Gorilla BoV). Capsid protein expression and efficient rAAV cross-packaging were validated by immunoblotting and qPCR, respectively. Interestingly, not only HBoV1 but also HBoV4 and GBoV transduced pHAEs as well as primary human lung organoids. Flow cytometry analysis of pHAEs revealed distinct cellular specificities between the BoV isolates, with HBoV1 targeting ciliated, club, and KRT5+ basal cells, whereas HBoV4 showed a preference for KRT5+ basal cells. Surprisingly, primary human hepatocytes, skeletal muscle cells, and T cells were also highly amenable to rAAV/BoV transduction. Finally, we adapted our pipeline for AAV capsid gene shuffling to all five BoV isolates. Collectively, our chimeric rAAV/BoV vectors and bocaviral capsid library represent valuable new resources to dissect BoV biology and to breed unique gene therapy vectors.

New Parvovirus Associated with Serum Hepatitis in Horses after Inoculation of Common Biological Product

Equine serum hepatitis (i.e., Theiler's disease) is a serious and often life-threatening disease of unknown etiology that affects horses. A horse in Nebraska, USA, with serum hepatitis died 65 days after treatment with equine-origin tetanus antitoxin. We identified an unknown parvovirus in serum and liver of the dead horse and in the administered antitoxin. The equine parvovirus-hepatitis (EqPV-H) shares <50% protein identity with its phylogenetic relatives of the genus Copiparvovirus. Next, we experimentally infected 2 horses using a tetanus antitoxin contaminated with EqPV-H. Viremia developed, the horses seroconverted, and acute hepatitis developed that was confirmed by clinical, biochemical, and histopathologic testing. We also determined that EqPV-H is an endemic infection because, in a cohort of 100 clinically normal adult horses, 13 were viremic and 15 were seropositive. We identified a new virus associated with equine serum hepatitis and confirmed its pathogenicity and transmissibility through contaminated biological products.

Detection and phylogenetic analysis of porcine bocaviruses carried by murine rodents and house shrews in China

Bocaparvovirus infections of humans and both wild and domestic animals have been widely reported around the world. In this study, we detected and genetically characterized porcine bocavirus (PBoV) carried by murine rodents (Rattus norvegicus, Rattus tanezumi, and Rattus losea) and house shrews (Suncus murinus) in China. Between May 2015 and May 2017, 496 murine rodents and 23 house shrews were captured in four Chinese provinces. Nested polymerase chain reaction was used to investigate the prevalence of PBoV in throat swab, faecal and serum samples. A total of 7.5% (39/519) throat swab samples, 60.5% (309/511) faecal samples, and 22.9% (52/227) serum samples were PBoV-positive. The prevalence among R. norvegicus and R. tanezumi was higher than that among R. losea and house shrews. PBoV-positive samples were found in all four provinces. Phylogenetic analysis based on partial viral capsid protein 1/2 (VP1/VP2) showed that sequences obtained in this study formed a novel group (PBoV G4). In addition, five near full-length PBoV genomes (4,715-4,798 nt) were acquired. These genomes encoded two non-structural proteins, NS1 (1,908 nt in four genomes and 1,923 nt in the remaining genome) and NP1 (600 nt), and the structural proteins, VP1/VP2 (1,851 nt). Phylogenetic analysis showed that PBoV G4 is distinct from rodent, human, and other bocaviruses. In conclusion, PBoV G4 prevalence was high among two common murine rodents in China, and the pathogenecity of PBoV G4 need to be further clarified.

Presence of rat bocavirus in oropharyngeal and fecal samples from murine rodents in China

In this study, we detected and genetically characterized rat bocavirus (RBoV) carried in 496 murine rodents that were captured in four provinces in China between May 2015 and May 2017. RBoV-positive samples were found in all four provinces, with a total positive rate of 24.8% (123/496) in throat swabs and 58.1% (286/492) in fecal samples. Twelve nearly full-length genome sequences of RBoV were determined, and the average sequence identity was 96.2%. Phylogenetic analysis showed that RBoVs formed a distinct clade that was distinguishable from the bocaviruses discovered in humans and other animals.

Detection of nineteen enteric viruses in raw sewage in Japan

One-year surveillance for enteric viruses in raw sewage was conducted in Kansai area, central part of Japan from July 2015 to June 2016. The raw sewage was collected monthly from an inlet polluted pool and was concentrated by polyethylene glycol (PEG) precipitation. Twelve sewage samples were screened for nineteen kinds of enteric viruses by using RT-PCR method and further analyzed by nucleotide sequencing. Twelve enteric viruses were found in the investigative sewage samples. Rotavirus A and norovirus GI and GII with several genotypes were detected all year round. Interestingly, norovirus GII.17 (Kawasaki-like strain) and rotavirus G2 that caused the outbreaks in Japan last epidemic season were also found in sewage. Moreover, adenovirus, astrovirus, sapovirus, bocavirus, human parechovirus, enterovirus, Aichi virus, Saffold virus and salivirus were also detected. Enterovirus D68 was detected only in the same month as those of enterovirus D68 outbreak in Japan. The rotavirus B and C, hepatitis A and E viruses, human cosavirus, bufavirus and rosavirus were not detected in this surveillance. The study provides the information on the enteric viruses contaminated in raw sewage, which is valuable for risk assessment. Our results imply that the viruses detected in sewage may be associated with infections in the Japanese population.

Identification and characterization of a novel rodent bocavirus from different rodent species in China

Members in the genus Bocaparvovirus are closely related to human health and have a wide host range. The diverse hosts raise the possibility of crossing species barrier, which is a feature of emerging viruses. Among the mammalian hosts, rodents are generally acknowledged to be important reservoirs of emerging viruses. Here, rodent samples collected from six provinces and autonomous regions of China (Liaoning, Inner Mongolia, Tibet, Xinjiang, Guangxi and Yunnan) were used to investigate the prevalence and distribution of bocaparvoviruses. By using next-generation sequencing first, a partial non-structural protein 1 (NS1) gene belonging to a possible novel bocaparvovirus was discovered. Following this, PCR-based screening of NS1 gene was conducted in 485 rodent samples, with 106 positive results found in seven rodent species (Rattus norvegicus, Mus musculus, Apodemus agrarius, Cricetulus barabensis, Rattus flavipectus, Rattus rattus and Rhombomys opimus). Finally, six nearly full-length genomes and three complete CDS were obtained and the newly identified bocaparvovirus was tentatively named rodent bocavirus (RoBoV). RoBoV has three ORFs: NS1, NP1, and VP, which are characteristics of bocaparvoviruses. Phylogenetic analyses revealed that porcine bocavirus isolate PBoV-KU14, a member of Ungulate bocaparvovirus 4, was the most related virus to RoBoV, with 92.1-92.9% amino acid identities in NS1 protein. Alignments of RoBoV-related sequences showed RoBoV isolates could be classified into two clades, demonstrating an inter-host genetic diversity. The results indicate a potential interspecies transmission of RoBoV between rodents and swine and expand our knowledge on bocaparvoviruses in rodent populations.

DNA indicative of human bocaviruses detected in non-human primates in the Democratic Republic of the Congo

Bocaparvoviruses are members of the family Parvovirinae and human bocaviruses have been found to be associated with respiratory and gastrointestinal disease. There are four known human bocaviruses, as well as several distinct ones in great apes. The goal of the presented study was to detect other non-human primate (NHP) bocaviruses in NHP species in the Democratic Republic of the Congo using conventional broad-range PCR. We found bocavirus DNA in blood and tissues samples in 6 out of 620 NHPs, and all isolates showed very high identity (>97 %) with human bocaviruses 2 or 3. These findings suggest cross-species transmission of bocaviruses between humans and NHPs.

First report of feline bocavirus associated with severe enteritis of cat in Northeast China, 2015

Feline bocavirus (FBoV) is a newly identified bocavirus of cats in the family Parvoviridae. A novel FBoV HRB2015-LDF was first identified from the cat with severe enteritis in Northeast China, with an overall positive rate of 2.78% (1/36). Phylogenetic and homologous analysis of the complete genome showed that FBoV HRB2015-LDF was clustered into the FBoV branch and closely related to other FBoVs, with 68.7–97.5% identities. And the genes of VP1, NPA and NS1 shared 70.7–97.6, 72.4–98.6 and 67.2–98.0% nucleotide identities with other FBoVs, respectively. The results suggested that the FBoVs could be divided into two distinct lineages, and the difference of nucleotide identities was >20–30% between the lineages.

The Role of the Human Bocavirus (HBoV) in Respiratory Infections

The human bocavirus is one of the most common respiratory viruses and occurs in all age groups. Because Koch’s postulates have been fulfilled unintendedly, it is currently accepted that the virus is a real pathogen associated with upper and lower respiratory tract infections causing clinical symptoms ranging from a mild common cold to life-threatening respiratory diseases. In order to exclude a viremia, serological analysis should be included during laboratory diagnostics, as acute and chronic infections cannot be differentiated by detection of viral nucleic acids in respiratory specimen alone due to prolonged viral shedding. Besides its ability to persist, the virus appears to trigger chronic lung disease and increases clinical symptoms by causing fibrotic lung diseases. Due to the lack of an animal model, clinical trials remain the major method for studying the long-term effects of HBoV infections.

First molecular detection of porcine bocavirus in Malaysia

Several strains of porcine bocaviruses have been reported worldwide since their first detection in Sweden in 2009. Subsequently, the virus has been reported to be associated with gastrointestinal and respiratory signs in weaner and grower pigs. Although Malaysia is host to a self-sufficient swine livestock industry, there is no study that describes porcine bocavirus in the country. This report is the first to describe porcine bocavirus (PBoV) in Malaysian swine herds. PBoV was identified in various tissues from sick and runt pigs using the conventional PCR method with primers targeting conserved regions encoding for the nonstructural protein (NS1) gene. Out of 103 samples tested from 17 pigs, 32 samples from 15 pigs were positive for porcine bocavirus. In addition, a higher detection rate was identified from mesenteric lymph nodes (52.9%), followed by tonsil (37.0%), and lungs (33.3%). Pairwise comparison and phylogenetic analyses based on a 658-bp fragment of NS1 gene revealed that the Malaysian PBoV strains are highly similar to PBoV3 isolated in Minnesota, USA. The presence of porcine bocavirus in Malaysia and their phylogenetic bond was marked for the first time by this study. Further studies will establish the molecular epidemiology of PBoV in Malaysia and clarify pathogenicity of the local isolates.

Two novel bocaparvovirus species identified in wild Himalayan marmots

Bocaparvovirus (BOV) is a genetically diverse group of DNA viruses and a possible cause of respiratory, enteric, and neurological diseases in humans and animals. Here, two highly divergent BOVs (tentatively named as Himalayan marmot BOV, HMBOV1 and HMBOV2) were identified in the livers and feces of wild Himalayan marmots in China, by viral metagenomic analysis. Five of 300 liver samples from Himalayan marmots were positive for HMBOV1 and five of 99 fecal samples from these animals for HMBOV2. Their nearly complete genome sequences are 4,672 and 4,887 nucleotides long, respectively, with a standard genomic organization and containing protein-coding motifs typical for BOVs. Based on their NS1, NP1, and VP1, HMBOV1 and HMBOV2 are most closely related to porcine BOV SX/1-2 (approximately 77.0%/50.0%, 50.0%/53.0%, and 79.0%/54.0% amino acid identity, respectively). Phylogenetic analysis of these three proteins showed that HMBOV1 and HMBOV2 formed two distinctly independent branches in BOVs. According to these results, HMBOV1 and HMBOV2 are two different novel species in the Bocaparvovirus genus. Their identification expands our knowledge of the genetic diversity and evolution of BOVs. Further studies are needed to investigate their potential pathogenicity and their impact on Himalayan marmots and humans.

Genome Sequence of a Porcine Bocavirus Detected in Feces of Domestic Minks in China

We report here the genome sequence of porcine bocavirus strain PBov-JZ08, which was isolated from mink feces in China. Sequence analysis implied that PBov-JZ08 clustered with three porcine bocaviruses.

Two novel dromedary camel bocaparvoviruses from dromedaries in the Middle East with unique genomic features

The recent emergence of Middle East respiratory syndrome (MERS) coronavirus and its discovery from dromedary camels has boosted interest in the search for novel viruses in dromedaries. While bocaparvoviruses are known to infect various animals, it was not known that they exist in dromedaries. In this study, we describe the discovery of two novel dromedary camel bocaparvoviruses (DBoVs), DBoV1 and DBoV2, from dromedary faecal samples in Dubai. Among 667 adult dromedaries and 72 dromedary calves, 13.9 % of adult dromedaries and 33.3 % of dromedary calves were positive for DBoV1, while 7.0 % of adult dromedaries and 25.0 % of dromedary calves were positive for DBoV2, as determined by PCR. Sequencing of 21 DBoV1 and 18 DBoV2 genomes and phylogenetic analysis showed that DBoV1 and DBoV2 formed two distinct clusters, with only 32.6-36.3 % amino acid identities between the DBoV1 and DBoV2 strains. Quasispecies were detected in both DBoVs. The amino acid sequences of the NS1 proteins of all the DBoV1 and DBoV2 strains showed <85 % identity to those of all the other bocaparvoviruses, indicating that DBoV1 and DBoV2 are two bocaparvovirus species according to the ICTV criteria. Although the typical genome structure of NS1-NP1-VP1/VP2 was observed in DBoV1 and DBoV2, no phospholipase A2 motif and associated calcium binding site were observed in the predicted VP1 sequences for any of the 18 sequenced DBoV2, and no start codons were found for their VP1. For all 18 DBoV2 genomes, an AT-rich region of variable length and composition was present downstream to NP1. Further studies will be crucial to understand the pathogenic potential of DBoVs in this unique group of animals.

Genomic recombination in primate bocavirus: inconsistency and alternative interpretations

Human bocavirus (HBoV) is a single-stranded DNA virus in Parvoviridae family, causing respiratory diseases in human. The recent identifications of genomic recombination among the four human bocavirus genotypes and related non-human primate bocaviruses have shed lights into the evolutionary processes underpinning the diversity of primate bocavirus. Among these reports, however, we found inconsistency and possible alternative interpretations of the recombination events. In this study, these recombination events were reviewed, and the related genome sequences were re-analysed, aiming to inform the research community of bocavirus with more consistent knowledge and comprehensive interpretations on the recombination history of primate bocavirus.

Human Parvoviruses

Parvovirus B19 (B19V) and human bocavirus 1 (HBoV1), members of the large Parvoviridae family, are human pathogens responsible for a variety of diseases. For B19V in particular, host features determine disease manifestations. These viruses are prevalent worldwide and are culturable in vitro, and serological and molecular assays are available but require careful interpretation of results. Additional human parvoviruses, including HBoV2 to -4, human parvovirus 4 (PARV4), and human bufavirus (BuV) are also reviewed. The full spectrum of parvovirus disease in humans has yet to be established. Candidate recombinant B19V vaccines have been developed but may not be commercially feasible. We review relevant features of the molecular and cellular biology of these viruses, and the human immune response that they elicit, which have allowed a deep understanding of pathophysiology.

DNA Damage Signaling Is Required for Replication of Human Bocavirus 1 DNA in Dividing HEK293 Cells

Human bocavirus 1 (HBoV1), an emerging human-pathogenic respiratory virus, is a member of the genus Bocaparvovirus of the Parvoviridae family. In human airway epithelium air-liquid interface (HAE-ALI) cultures, HBoV1 infection initiates a DNA damage response (DDR), activating all three phosphatidylinositol 3-kinase-related kinases (PI3KKs): ATM, ATR, and DNA-PKcs. In this context, activation of PI3KKs is a requirement for amplification of the HBoV1 genome (X. Deng, Z. Yan, F. Cheng, J. F. Engelhardt, and J. Qiu, PLoS Pathog, 12:e1005399, 2016, https://doi.org/10.1371/journal.ppat.1005399), and HBoV1 replicates only in terminally differentiated, nondividing cells. This report builds on the previous discovery that the replication of HBoV1 DNA can also occur in dividing HEK293 cells, demonstrating that such replication is likewise dependent on a DDR. Transfection of HEK293 cells with the duplex DNA genome of HBoV1 induces hallmarks of DDR, including phosphorylation of H2AX and RPA32, as well as activation of all three PI3KKs. The large viral nonstructural protein NS1 is sufficient to induce the DDR and the activation of the three PI3KKs. Pharmacological inhibition or knockdown of any one of the PI3KKs significantly decreases both the replication of HBoV1 DNA and the downstream production of progeny virions. The DDR induced by the HBoV1 NS1 protein does not cause obvious damage to cellular DNA or arrest of the cell cycle. Notably, key DNA replication factors and major DNA repair DNA polymerases (polymerase η [Pol η] and polymerase κ [Pol κ]) are recruited to the viral DNA replication centers and facilitate HBoV1 DNA replication. Our study provides the first evidence of the DDR-dependent parvovirus DNA replication that occurs in dividing cells and is independent of cell cycle arrest.

IMPORTANCE

The parvovirus human bocavirus 1 (HBoV1) is an emerging respiratory virus that causes lower respiratory tract infections in young children worldwide. HEK293 cells are the only dividing cells tested that fully support the replication of the duplex genome of this virus and allow the production of progeny virions. In this study, we demonstrate that HBoV1 induces a DDR that plays significant roles in the replication of the viral DNA and the production of progeny virions in HEK293 cells. We also show that both cellular DNA replication factors and DNA repair DNA polymerases colocalize within centers of viral DNA replication and that Pol η and Pol κ play an important role in HBoV1 DNA replication. Whereas the DDR that leads to the replication of the DNA of other parvoviruses is facilitated by the cell cycle, the DDR triggered by HBoV1 DNA replication or NS1 is not. HBoV1 is the first parvovirus whose NS1 has been shown to be able to activate all three PI3KKs (ATM, ATR, and DNA-PKcs).

Identification and genomic characterization of a novel rat bocavirus from brown rats in China

Despite recent discoveries of novel animal bocaparvoviruses, current understandings on the diversity and evolution of bocaparvoviruses are still limited. We report the identification and genome characterization of a novel bocaparvovirus, rat bocaparvovirus (RBoV), in brown rats (Rattus norvegicus) in China. RBoV was detected in 11.5%, 2.4%, 16.2% and 0.3% of alimentary, respiratory, spleen and kidney samples respectively, of 636 brown rats by PCR, but not in samples of other rodent species, suggesting that brown rats are the primary reservoir of RBoV. Six RBoV genomes sequenced from three brown rats revealed the presence of three ORFs, characteristic of bocaparvoviruses. Phylogenetic analysis showed that RBoV was distantly related to other bocaparvoviruses, forming a distinct cluster within the genus, with ≤55.5% nucleotide identities to the genome of ungulate bocaparvovirus 3, supporting its classification as a novel bocaparvovirus species. RBoV possessed a putative second exon encoding the C-terminal region of NS1 and conserved RNA splicing signals, similar to human bocaparvoviruses and canine bocaparvovirus. In contrast to human, feline and canine bocaparvoviruses which demonstrates inter/intra-host viral diversity, partial VP1/VP2 sequences of 49 RBoV strains demonstrated little inter-host genetic diversity, suggesting a single genetic group. Although the pathogenicity of RBoV remains to be determined, its presence in different host tissues suggests wide tissue tropism. RBoV represents the first bocaparvovirus in rodents with genome sequenced, which extends our knowledge on the host range of bocaparvoviruses. Further studies are required to better understand the epidemiology, genetic diversity and pathogenicity of bocaparvoviruses in different rodent populations.

Multiplex RT-PCR for rapid detection of viruses commonly causing diarrhea in pediatric patients

Multiplex RT-PCR method using five sets of panel primers was developed for the detection of diarrheal viruses, including rotavirus A, B, and C, adenovirus, astrovirus, norovirus GI and GII, sapovirus, Aichi virus, parechovirus, enterovirus, cosavirus, bocavirus, and Saffold virus. The sensitivity of the method was evaluated and tested with 751 fecal specimens collected from Japanese children with acute diarrhea. Several kinds of viruses were detected in 528 out of 751 (70.3%) fecal specimens. Mixed-infection with different viruses in clinical specimens could also be effectively detected. The method proved to be reliable with highly sensitive and specific and useful for routine diagnosis. J. Med. Virol. 89:818-824, 2017. © 2016 Wiley Periodicals, Inc.

Identification and interspecies transmission of a novel bocaparvovirus among different bat species in China

We report the discovery of a novel bocaparvovirus, bat bocaparvovirus (BtBoV), in one spleen, four respiratory and 61 alimentary samples from bats of six different species belonging to three families, Hipposideridae, Rhinolophidae and Vespertilionidae. BtBoV showed a higher detection rate in alimentary samples of Rhinolophus sinicus (5.7 %) than those of other bat species (0.43-1.59 %), supporting R. sinicus as the primary reservoir and virus spillover to accidental bat species. BtBoV peaked during the lactating season of R. sinicus, and it was more frequently detected among female than male adult bats (P<0.05), and among lactating than non-lactating female bats (P<0.0001). Positive BtBoV detection was associated with lower body weight in lactating bats (P<0.05). Ten nearly complete BtBoV genomes from three bat species revealed a unique large ORF1 spanning NS1 and NP1 in eight genomes and conserved splicing signals leading to multiple proteins, as well as a unique substitution in the conserved replication initiator motif within NS1. BtBoV was phylogenetically distantly related to known bocaparvoviruses with ≤57.3 % genome identities, supporting BtBoV as a novel species. Ms-BtBoV from Miniopterus schreibersii and Hp-BtBoV from Hipposideros pomona demonstrated 97.2-99.9 % genome identities with Rs-BtBoVs from R. sinicus, supporting infection of different bat species by a single BtBoV species. Rs-BtBoV_str15 represents the first bat parvovirus genome with non-coding regions sequenced, which suggested the presence of head-to-tail genomic concatamers or episomal forms of the genome. This study represents the first to describe interspecies transmission in BoVs. The high detection rates in lactating female and juvenile bats suggest possible vertical transmission of BtBoV.

Analysis of cis and trans Requirements for DNA Replication at the Right-End Hairpin of the Human Bocavirus 1 Genome

Parvoviruses are single-stranded DNA viruses that use the palindromic structures at the ends of the viral genome for their replication. The mechanism of parvovirus replication has been studied mostly in the dependoparvovirus adeno-associated virus 2 (AAV2) and the protoparvovirus minute virus of mice (MVM). Here, we used human bocavirus 1 (HBoV1) to understand the replication mechanism of bocaparvovirus. HBoV1 is pathogenic to humans, causing acute respiratory tract infections, especially in young children under 2 years old. By using the duplex replicative form of the HBoV1 genome in human embryonic kidney 293 (HEK293) cells, we identified the HBoV1 minimal replication origin at the right-end hairpin (OriR). Mutagenesis analyses confirmed the putative NS1 binding and nicking sites within the OriR. Of note, unlike the large nonstructural protein (Rep78/68 or NS1) of other parvoviruses, HBoV1 NS1 did not specifically bind OriR in vitro, indicating that other viral and cellular components or the oligomerization of NS1 is required for NS1 binding to the OriR. In vivo studies demonstrated that residues responsible for NS1 binding and nicking are within the origin-binding domain. Further analysis identified that the small nonstructural protein NP1 is required for HBoV1 DNA replication at OriR. NP1 and other viral nonstructural proteins (NS1 to NS4) colocalized within the viral DNA replication centers in both OriR-transfected cells and virus-infected cells, highlighting a direct involvement of NP1 in viral DNA replication at OriR. Overall, our study revealed the characteristics of HBoV1 DNA replication at OriR, suggesting novel characteristics of autonomous parvovirus DNA replication.

IMPORTANCE

Human bocavirus 1 (HBoV1) causes acute respiratory tract infections in young children. The duplex HBoV1 genome replicates in HEK293 cells and produces progeny virions that are infectious in well-differentiated airway epithelial cells. A recombinant AAV2 vector pseudotyped with an HBoV1 capsid has been developed to efficiently deliver the cystic fibrosis transmembrane conductance regulator gene to human airway epithelia. Here, we identified both cis-acting elements and trans-acting proteins that are required for HBoV1 DNA replication at the right-end hairpin in HEK293 cells. We localized the minimal replication origin, which contains both NS1 nicking and binding sites, to a 46-nucleotide sequence in the right-end hairpin. The identification of these essential elements of HBoV1 DNA replication acting both in cis and in trans will provide guidance to develop antiviral strategies targeting viral DNA replication at the right-end hairpin and to design next-generation recombinant HBoV1 vectors, a promising tool for gene therapy of lung diseases.

A novel bocavirus from domestic mink, China

Bocaviruses have been found in the feces of humans and a variety of animals, including pigs, cattle, dogs, gorillas, cats, and sea lions. Here, we have characterized the almost complete genome (5224 nt) of a novel bocavirus from feces of domestic minks, which has been provisionally named mink bocavirus. The NS1 protein of mink bocavirus shared 36.9-52 % amino acid sequence identities with those of other known bocaviruses and phylogenetically clustered with bocaviruses from other carnivores. According to the genetic distance-based criteria, mink bocavirus qualifies as a novel species of bocavirus. PCR of feces from a group of domestic minks, which included both healthy animals and animals suffering from diarrhea, revealed that 30 % (9/30) shed virus. However, no association between viral shedding and the presence of diarrhea could be determined.

Development and validation of a multiplex conventional PCR assay for simultaneous detection and grouping of porcine bocaviruses

Porcine bocavirus (PBoV), a newly described porcine parvovirus, has received attention because it can be commonly identified in clinically affected pigs including pigs with post-weaning multisystemic wasting syndrome (PWMS) and pigs with diarrhea. In recent years, novel PBoVs have been identified and were classified into three genogroups, but the ability to detect and classify these novel PBoVs is not comprehensive to date. In this study, a multiplex conventional PCR assay for simultaneous detection and grouping of PBoVs was developed by screening combinations of mixed primer pairs followed by optimization of the PCR conditions. This method exclusively amplifies targeted fragments of 531bp from the VP1 gene of PBoV G1, 291bp from the NP1 gene of PBoV G2, and 384bp from the NP1/VP1 gene of PBoV G3. The assay has a detection limit of 1.0×10(3)copies/μL for PBoV G1 4.5×10(3) for PBoV G2 and 3.8×10(3) for PBoV G3 based on testing mixed purified plasmid constructs containing the specific viral target fragments. The performance of the multiplex PCR assay was comparable to that of the single PCRs which used the same primer pairs. Using the newly established multiplex PCR assay, 227 field samples including faeces, serum and tissue samples from pigs were investigated. All three PBoV genogroups were detected in the clinical samples with a detection rate of 1.3%, 2.6% and 12.3%, respectively for PBoV G1, G2 and G3. Additionally, coinfections with two or more PBoV were detected in 1.7% of the samples investigated. These results indicate the multiplex PCR assay is specific, sensitive and rapid, and can be used for the detection and differentiation of single and multiple infections of the three PBoV genogroups in pigs.

[Natural reservoirs of viruses of the genus Hepacivirus, Flaviviridae]

HCV is a cause of acute and chronic liver diseases, including chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Under natural conditions, HCV is able to infect only humans, and only chimpanzees are sensitive to experimental infection. In recent years, viruses genetically related to HCV were discovered in wild mammals (rodents, bats, rabbits), as well as in domestic animals living in close contact with humans (dogs, horses, cows). The hepacivirus genus of the family Flaviviridae, previously represented only by HCV and, presumably, by GBV-B, now includes new related viruses of animals. The results of the study of molecular-genetic and biological properties of the hepaciviruses provide an opportunity to understand the history, evolution, and the origin of HCV. It also opens up the prospect of using HCV homologues of non-primates as a laboratory model for preclinical medical and prophylactic drugs against hepatitis c. It was found that the hepacivirus of horses is the most closely related to HCV among currently known HCV homologues.

Epidemiological investigation reveals genetic diversity and high co-infection rate of canine bocavirus strains circulating in Heilongjiang province, Northeast China

To trace evolution of CBoV in Northeast China, 201 fecal samples from rectal swabs of diarrheic dogs collected from May 2014 to April 2015 were investigated using PCR targeting partial NS1 gene (440 bp). Furthermore, phylogenetic analysis of the identified CBoV strains was conducted using nucleotide sequences of the partial NS1 gene. The results indicated that 15 of 201 fecal samples (7.5%) were positive for CBoV; the partial NS1 genes of the 15 CBoV strains exhibited 83.1%–100% nucleotide identity, and 75.8%–100% amino acid identity; the entire VP2 gene of five selected CBoV strains exhibited 82.9%–96.8% nucleotide identity, and 90.4%–99.1% amino acid identity. The 15 CBoV strains exhibited high co-infection rates with CPV-2 (40%), CCoV (20%), and CaKV (26.67%). Phylogenetic analysis of the partial NS1 gene revealed that the 15 CBoV strains were divided into different subgroups of CBoV-2 when compared with CBoV-2 strains from South Korea, USA, Germany, and Hong Kong in China. Moreover, phylogenetic analysis of the VP2 gene indicated that five selected CBoV strains were divided into three different genetic groups of CBoV-2, involving in CBoV-2HK group, CBoV-2C group, and CBoV-2B group. The recombination analysis using the entire VP2 gene revealed three potential recombination events that occurred among five selected strains in our study. These data demonstrated that the CBoV strains circulating in Heilongjiang province, Northeast China showed genetic diversities, potential recombination events, and high co-infection rate. Further studies will be required to address the potential pathogenic role of these diverse CBoV strains.

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Canine bocavirus (CBoV) exhibits high prevalence in Northeast China from 2.8% to 20%.

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We revealed high co-infection of CBoV with canine parvovirus-2, canine coronavirus, and canine kobuvirus.

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The CBoV strains circulating in Northeast China show multiple genetic groups.

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Potential recombination events occur among the CBoV strains circulating in Northeast China.

Genetic and phylogenetic characterization of novel bocaparvovirus infecting chimpanzee

Primate bocaparvoviruses were first described in 2005, since then further human and gorilla bocaparvoviruses have been identified. To uncover diversity of non-human primates' bocaparvoviruses, their phylogenetic relationship and potential to cross the host species barrier, we tested 153 fecal samples from 17 captive primate species. The only one captive female of central chimpanzee (coded CPZh2) has been identified as bocaparvovirus positive. Based on the full genome phylogenetic analyses, CPZh2 strain shows close relationship to HBoV3 and GBoV. Further recombination analysis confirmed expected mosaic origin of CPZh2 strain. According the phylogenetic position, following the ICTV recommendations, we propose a novel genotype within the Primate bocaparvovirus 1 species infecting chimpanzee.

Virome Analysis of Transfusion Recipients Reveals a Novel Human Virus That Shares Genomic Features with Hepaciviruses and Pegiviruses

To investigate the transmission of novel infectious agents by blood transfusion, we studied changes in the virome composition of blood transfusion recipients pre- and posttransfusion. Using this approach, we detected and genetically characterized a novel human virus, human hepegivirus 1 (HHpgV-1), that shares features with hepatitis C virus (HCV) and human pegivirus (HPgV; formerly called GB virus C or hepatitis G virus). HCV and HPgV belong to the genera Hepacivirus and Pegivirus of the family Flaviviridae. HHpgV-1 was found in serum samples from two blood transfusion recipients and two hemophilia patients who had received plasma-derived clotting factor concentrates. In the former, the virus was detected only in the posttransfusion samples, indicating blood-borne transmission. Both hemophiliacs were persistently viremic over periods of at least 201 and 1,981 days. The 5′ untranslated region (UTR) of HHpgV-1 contained a type IV internal ribosome entry site (IRES), structurally similar to although highly divergent in sequence from that of HCV and other hepaciviruses. However, phylogenetic analysis of nonstructural genes (NS3 and NS5B) showed that HHpgV-1 forms a branch within the pegivirus clade distinct from HPgV and homologs infecting other mammalian species. In common with some pegivirus variants infecting rodents and bats, the HHpgV-1 genome encodes a short, highly basic protein upstream of E1, potentially possessing a core-like function in packaging RNA during assembly. Identification of this new human virus, HHpgV-1, expands our knowledge of the range of genome configurations of these viruses and may lead to a reevaluation of the original criteria by which the genera Hepacivirus and Pegivirus are defined.

More than 30 million blood components are transfused annually in the United States alone. Surveillance for infectious agents in the blood supply is key to ensuring the safety of this critical resource for medicine and public health. Here, we report the identification of a new and highly diverse HCV/GB virus (GBV)-like virus from human serum samples. This new virus, human hepegivirus 1 (HHpgV-1), was found in serum samples from blood transfusion recipients, indicating its potential for transmission via transfusion products. We also found persistent long-term HHpgV-1 viremia in two hemophilia patients. HHpgV-1 is unique because it shares genetic similarity with both highly pathogenic HCV and the apparently nonpathogenic HPgV (GBV-C). Our results add to the list of human viruses and provide data to develop reagents to study virus transmission and disease association and for interrupting virus transmission and new human infections.

Genetic characteristics of canine bocaviruses in Korean dogs

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CBoV strains causing infections in 83 Korean dogs were surveyed.

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Strains 13D003, 13D0095, 14D142, and 14D193 had pathogenicity in young puppy.

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These 4 strains also did not contain the ORF region.

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Absence of the ORF4 region may influence CBoV pathogenesis in dogs.

To survey for canine bocavirus (CBoV) infection, 83 Korean dogs showing several clinical signs were collected in different provinces from January 2013 to July 2014. Using polymerase chain reaction (PCR) and in situ hybridization, CBoVs were detected in intestine and/or lung samples of 8 dogs (9.6%). To reveal the genetic characteristics of CBoVs, partial or complete regions of CBoVs were sequenced. In phylogenetic trees, 8 CBoVs fell into three clusters. The CBoV strains 13D226-1, 13D250, and 14Q216 were closely related to the CBoV HK831F strain, and the CBoV 14D142 strain was related to the CBoV HK882F strain. Lastly, CBoV 13D003, 13D095, 14D193, and 14Q209 strains were related to CBoV Dis-023, Dis-040, and Dis-046 strains. Interestingly, no canine pathogens were found in dogs in which four CBoVs (13D003, 13D0095, 14D142, and 14D193 strains) were detected and three of them (13D003, 13D095, and 14D193 strains) had a unique deletion (18 nucleotides) in the VP2 gene. Further, the open reading frame 4 (ORF4) region was absent in these 4CBoVs, but found in the other strains, which indicates that the absence of the ORF4 region rather than a unique deletion may have an influence on the pathogenesis of CBoV in dogs.