A minute virus of canines (MVC: canine bocavirus) isolated from an elderly dog with severe gastroenteritis, and phylogenetic analysis of MVC strains

Carnivore chaphamaparvovirus-1 (CaChPV-1) infection in diarrheic dogs reveals viral endotheliotropism in intestine and lung

BACKGROUND

Carnivore chaphamaparvovirus-1 (CaChPV-1) is a parvovirus identified in dogs and association of infection with diarrhea is controversial. Information on whether tissue tropism persists is lacking.

OBJECTIVES

To determine the disease association of CaChPV-1 in dogs with diarrhea and to investigate viral tropism and genetic diversity.

ANIMALS AND METHODS

CaChPV-1 infection was investigated in five recently deceased puppies and designed a retrospective study to determine whether the presence of CaChPV-1 is associated with diarrhea. The retrospective study was conducted in 137 intestinal tissue samples and 168 fecal samples obtained from 305 dogs. CaChPV-1 tissue localization was determined using in situ hybridization, and CaChPV-1 complete genomes obtained from dead puppies and retrospective study were sequenced and analyzed.

RESULTS

CaChPV-1 was detected in 6.56% (20/305) of tested dogs, including 14 diarrheic- and 6 non-diarrheic dogs, and was significant in puppies with diarrhea (p = 0.048). Among the CaChPV-1-positive diarrheic dogs, one sample was obtained from intestinal tissue and 13 samples were fecal samples. However, six CaChPV-1 positive non-diarrheic dogs were based on fecal samples but not on intestinal tissue. Within the age range, the presence of CaChPV-1 was significant in puppies (p < 0.00001) and was mainly localized in the stromal and endothelial cells of intestinal villi and pulmonary alveoli. Phylogenetic analysis indicated genetic diversity of CaChPV-1 Thai strains that were mostly clustered within the sequences found in China.

CONCLUSIONS

Although definitive pathogenesis of CaChPV-1 remains undetermined, this study provides evidence supporting that CaChPV-1 localizes in canine cells and could play a potential role as an enteric pathogen.

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.

Divergent minute virus of canines strains identified in illegally imported puppies in Italy

Minute virus of canines (MVC) belongs to the family Parvoviridae, genus Bocaparvovirus, and has been mainly described during enteritis episodes in young dogs. This study reports the characterization of four divergent MVC strains detected between 2012 and 2018, three of which were from dogs illegally imported into Italy, most probably from Eastern Europe, that cluster together phylogenetically but share low genetic similarity with the fourth MVC from an autochthonous dog and other available MVC sequences. Our data indicate that the introduction of genetically distinct MVC strains occurred through the illegal movement of dogs from a geographic area where a distinct MVC lineage was most likely circulating. Enforced surveillance of MVC in the dog population of Eastern Europe and its neighboring countries may shed light on, and eventually trace back to, illegal animal movements.

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.

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.

A novel recombinant genome of minute virus of canines in China

In this study, we determined almost all of the genome sequence of minute virus of canines (MVC) strain CDK47/2017 and performed phylogenetic analysis with this isolate and other MVC isolates. The genome of CDK47/2017 has the following characteristics: 1) The amino acid sequence of the NS1 protein is similar to that of the novel strain 15D009/KT241026.1, which has 17 identical amino acid changes and two identical amino acid insertions compared with other known MVC strains. These two strains clustered in a unique branch in an NSI-based phylogenetic tree. 2) Phylogenetic analysis based on the NP1 protein showed that strain CDK47/2017clustered in an independent branch with strains 15D009/KT241026.1 and HM-6/AB158475.1, both of which has 10 identical amino acid changes compared with other known MVC strains. 3) Eight unique amino acid substitutions of the CDK47/2017 capsid protein resulted in it forming a unique branch in the phylogenetic tree. 4) Recombination events were identified between the 3' end of the NS1 gene and 5' end of NP1 gene. Together, these characteristics suggest that strain CDK47/2017 represents a novel MVC strain that is distinct from all known MVC strains with sequences in the GenBank database. This contributes to a greater understanding of the genetic evolution of MVC.

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.

Canine Bocavirus Type 2 Infection Associated With Intestinal Lesions

Bocaviruses are small nonenveloped DNA viruses belonging to the Bocaparvovirus genus of the Parvoviridae family and have been linked to both respiratory and enteric disease in humans and animals. To date, 3 bocaviruses, canine bocaviruses 1 to 3 (CBoV-1-3), have been shown to affect dogs with different disease manifestations reported for infected animals. We used next-generation sequencing to identify a novel strain of canine CBoV-2 (CBoV TH-2016) in a litter of puppies that died in Thailand from acute dyspnea and hemoptysis, for which no causal pathogen could be identified in routine assays. Analysis of the complete coding sequences of CBoV TH-2016 showed that this virus was most closely related to a strain previously identified in South Korea (isolate 14D193), with evidence of genetic recombination in the VP2 gene with related strains from South Korea and Hong Kong. Use of quantitative polymerase chain reaction showed the presence of CBoV TH-2016 in several tissues, suggesting hematogenous virus spread, while only intestinal tissue was found to be positive by in situ hybridization and electron microscopy. Histologic small intestinal lesions associated with CBoV TH-2016 infection were eosinophilic intranuclear inclusion bodies within villous enterocytes without villous atrophy or fusion, similar to those previously considered pathognomonic for CBoV-1 infection. Therefore, this study provides novel insights in the pathogenicity of canine bocavirus infections and suggests that a novel recombinant CBoV-2 may result in atypical findings of CBoV infection. Although the specific cause of death of these puppies remained undetermined, a contributory role of enteric CBoV TH-2016 infection is possible.

Bocavirus-Nachweis bei 4 Wochen alten Welpen mit akutem Durchfall

Zwei 4 Wochen alte, weibliche Dobermann-Welpen wurden mit akutem Durchfall und Erbrechen vorgestellt. Zusätzlich zeigten sie Niesen und Nasenausfluss. Aufgrund der klinischen Präsentation und einer Neutropenie bestand der hochgradige Verdacht einer Parvovirose. Die Tiere blieben mehrere Tage hospitalisiert und wurden symptomatisch therapiert. Eine parasitologische Kotuntersuchung sowie eine virologische Untersuchung des Kots auf eine Parvovirusinfektion (Polymerasekettenreaktion [PCR] und Immunelektronenmikroskopie) verliefen negativ. Mithilfe einer weiteren, neuen PCR ließ sich das Bocavirus identifizieren, sodass eine Infektion mit diesem Erreger als mögliche Diagnose infrage kommt. Dieser Fallbericht beschreibt eine noch wenig bekannte virale Welpenerkrankung mit erfolgreichem Therapieverlauf.

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.

Viral gut metagenomics of sympatric wild and domestic canids, and monitoring of viruses: Insights from an endangered wolf population

Animal host-microbe interactions are a relevant concern for wildlife conservation, particularly regarding generalist pathogens, where domestic host species can play a role in the transmission of infectious agents, such as viruses, to wild animals. Knowledge on viral circulation in wild host species is still scarce and can be improved by the recent advent of modern molecular approaches. We aimed to characterize the fecal virome and identify viruses of potential conservation relevance of diarrheic free-ranging wolves and sympatric domestic dogs from Central Portugal, where a small and threatened wolf population persists in a highly anthropogenically modified landscape. Using viral metagenomics, we screened diarrheic stools collected from wolves (n = 8), feral dogs (n = 4), and pet dogs (n = 6), all collected within wolf range. We detected novel highly divergent viruses as well as known viral pathogens with established effects on population dynamics, including canine distemper virus, a novel bocavirus, and canine minute virus. Furthermore, we performed a 4-year survey for the six wolf packs comprising this endangered wolf population, screening 93 fecal samples from 36 genetically identified wolves for canine distemper virus and the novel bocavirus, previously identified using our metagenomics approach. Our novel approach using metagenomics for viral screening in noninvasive samples of wolves and dogs has profound implications on the knowledge of both virology and wildlife diseases, establishing a complementary tool to traditional screening methods for the conservation of threatened species.

First complete genome sequence of canine bocavirus 2 in mainland China

We obtained the first full-length genome sequence of canine bocavirus 2 (CBoV2) from the faeces of a healthy dog in Guangzhou city, Guangdong province, mainland China. The genome of GZHD15 consisted of 5059 nucleotides. Sequence analysis suggested that GZHD15 was close to a previously circulated Hong Kong isolate.

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.

Genetic characterization of feline bocavirus detected in cats in Japan

Feline bocavirus (FBoV) has been classified into three genotypes (FBoV1-FBoV3). FBoVs are mainly detected in feces. In the present study, we collected rectal swabs from cats in Japan and examined the samples for the presence of FBoV. The FBoV infection rate was 9.9 % in 101 cats. No significant association was observed between FBoV infection and clinical symptoms. Based on the full-length NS1 protein, the three strains of FBoVs detected in the present study shared high homologies with the genotype 2 FBoV POR1 strain. This is the first study to report FBoV in Japan.

Molecular characteristics of a novel strain of canine minute virus associated with hepatitis in a dog

A 5-year-old female Yorkshire terrier dog died a few days following hernia and ovariohysterectomy surgeries. Necropsy performed on the dog revealed that the surgeries were not the cause of death; however, degenerative viral hepatitis, showing intranuclear inclusion bodies in hepatic cells, was observed in histopathologic examination. Several diagnostic methods were used to screen for the cause of disease, and minute virus of canines (MVC) was detected in all parenchymal organs, including the liver. Other pathogens that may cause degenerative viral hepatitis were not found. Infection with MVC was confirmed by in situ hybridization, which revealed the presence of MVC nucleic acid in the liver tissue of the dog. Through sequencing and phylogenetic analysis of the nearly complete genome sequence, the strain was found to be distinct from other previously reported MVC strains. These results indicate that this novel MVC strain might be related to degenerative viral hepatitis in dogs.

Novel bocaparvoviruses in rabbits

Bocaparvovirus is a newly established genus within the family Parvoviridae and has been identified as a possible cause of enteric, respiratory, reproductive/neonatal and neurological disease in humans and several animal species. In this study, metagenomic analysis was used to identify and characterise a novel bocaparvovirus in the faeces of rabbits with enteric disease. To assess the prevalence of the novel virus, rectal swabs and faecal samples obtained from rabbits with and without diarrhoea were screened with a specific PCR assay. The complete genome sequence of the novel parvovirus was reconstructed. The virus was distantly related to other bocaparvoviruses; the three ORFs shared 53%, 53% and 50% nucleotide identity, respectively, to homologous genes of porcine bocaparvoviruses. The virus was detected in 8/29 (28%) and 16/95 (17%) samples of rabbits with and without diarrhoea, respectively. Sequencing of the capsid protein fragment targeted by the diagnostic PCR identified two distinct bocaparvovirus populations/sub-types, with 91.7-94.5% nucleotide identity to each other. Including these novel parvoviruses in diagnostic algorithms of rabbit diseases might help inform their potential pathogenic role and impact on rabbit production and the virological profiles of laboratory rabbits.

A novel bocavirus in canine liver

BACKGROUND

Bocaviruses are classified as a genus within the Parvoviridae family of single-stranded DNA viruses and are pathogenic in some mammalian species. Two species have been previously reported in dogs, minute virus of canines (MVC), associated with neonatal diseases and fertility disorders; and Canine bocavirus (CBoV), associated with respiratory disease.

FINDINGS

In this study using deep sequencing of enriched viral particles from the liver of a dog with severe hemorrhagic gastroenteritis, necrotizing vasculitis, granulomatous lymphadenitis and anuric renal failure, we identified and characterized a novel bocavirus we named Canine bocavirus 3 (CnBoV3). The three major ORFs of CnBoV3 (NS1, NP1 and VP1) shared less than 60% aa identity with those of other bocaviruses qualifying it as a novel species based on ICTV criteria. Inverse PCR showed the presence of concatemerized or circular forms of the genome in liver.

CONCLUSIONS

We genetically characterized a bocavirus in a dog liver that is highly distinct from prior canine bocaviruses found in respiratory and fecal samples. Its role in this animal's complex disease remains to be determined.

Host range of Canine minute virus in cell culture

Canine minute virus (CnMV) is a member of the Bocavirus genus, together with Bovine parvovirus (BPV), which emerged as a new pathogen of dogs in 1967. The genus Bocavirus gained more recognition after the recent identification of Human bocavirus in pooled specimens from the respiratory tract of children. The cell culture host range of CnMV appears to be restricted to the Walter Reed canine cell (WRCC) line, although there is a report that indicates susceptibility of the Madin-Darby canine kidney (MDCK) cell line. In order to study the susceptibility of different cell lines to CnMV, the replication in cell cultures of canine, bovine, and human origin and the interaction of the virus with freshly isolated canine peripheral blood mononuclear cells were evaluated. The in vitro host range was unexpectedly wide. As shown by indirect fluorescent antibody and polymerase chain reaction assays, CnMV replicates efficiently in the A72 and MDCK canine cell lines. Bovine and human cell lines support the replication of CnMV less efficiently. In contrast, canine mononuclear blood cells are permissive to replication of CnMV in vitro. The present study revealed the ability of CnMV to replicate in continuous cell lines of different origin and, partially, in canine mononuclear cells.

Molecular characterization of Canine minute virus associated with neonatal mortality in a litter of Jack Russell terrier dogs

The molecular characterization of a strain of Canine minute virus (CnMV) associated with neonatal death is reported. Three newborn puppies of a litter of Jack Russell terrier dogs died after displaying systemic disease, whereas 2 surviving puppies showed no clinical signs with the exception of transient cardiac abnormalities that were evident by electrocardiography. Necropsy of 1 dead puppy revealed severe lesions in the internal organs. A strain of Canine minute virus was detected in tissue samples collected from the puppy, and virus circulation was demonstrated by molecular or serological testing in the dam, puppies of the same litter, and other puppies in the same kennel. By sequence and phylogenetic analysis of the gene encoding for the VP2 capsid protein, the strain circulating in the kennel was found to be related to recent Asian CnMV isolates. Continuous molecular surveillance for CnMV in kennels, shelters, and rescue centers would expand the knowledge base on the epidemiological and pathogenetic features of CnMV, which has been known for several decades but still poorly understood.