Novel canine bocavirus strain associated with severe enteritis in a dog litter

Molecular Surveillance for Bocaparvoviruses and Bufaviruses in the European Hedgehog (Erinaceus europaeus)

The presence of bocaparvoviruses (BoVs) and bufaviruses (BuVs) in the European hedgehog (Erinaceus europaeus) was investigated by screening duodenal and liver samples collected from 183 carcasses, delivered to wildlife rescue centers located in northwestern Italy. BoV DNA was detected in 15 animals (8.2%), with prevalences of 7.1% (13/183) and 2.7% (5/183) in intestine and liver samples, respectively. Upon the sequence analyses of the NS1 gene, two highly divergent BoVs (65.5-67.8% nt identities) were identified. Fourteen strains showed the highest identity (98.3-99.4% nt) to the hedgehog BoV strains recently detected in China in Amur hedgehogs (Erinaceus amurensis), whilst four strains were genetically related (98.9-99.4% nt identities) to the porcine BoVs identified in pigs and classified in the species Bocaparvovirus ungulate 4, which included related viruses also found in rats, minks, shrews, and mice. BuV DNA was detected in the duodenal samples of two hedgehogs, with a prevalence rate of 1.1%. The nearly full-length genome of two BuV strains, Hedgehog/331DU-2022/ITA and Hedgehog/1278DU/2019/ITA, was reconstructed. Upon phylogenetic analysis based on the NS and VP aa sequences, the Italian hedgehog BuVs tightly clustered with the BuVs recently identified in the Chinese Amur hedgehogs, within a potential novel candidate species of the genus Protoparvovirus.

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.

Suttonella ornithocola detected within lesions of tit birds (Paridae) from epidemic death episodes in Germany, 2018–2020

Several episodes of increased mortality in wild birds of the families Paridae and Aegithalidae have been documented in recent decades. The majority of affected animals exhibited necrotizing pneumonia with intralesional bacteria. Suttonella (S.) ornithocola, a gram-negative bacterium in the Cardiobacteriaceae family, has been regularly cultured bacteriologically from affected birds and has long been suspected as a potentially fatal cause of respiratory disease in birds. However, a direct causal relationship between this specific bacterium and the observed lesions within birds has not yet been established. Therefore, postmortem tissue from six tits was used in the present study, including three blue tits (Cyanistes caeruleus) and three great tits (Parus major). Five of the six tits tested positive for S. ornithocola in bacteriological examination and originated from two incidents of increased mortality in Paridae in Germany. Animals found dead in the administrative district of Arnsberg (North Rhine Westphalia) in 2018 and 2020 were investigated for genomic fragments of S. ornithocola by chromogenic in situ hybridization using a newly developed DNA probe based on publicly assessable DNA sequences of the 16S rRNA gene of S. ornithocola. Positive hybridization signals were detected in five out of five animals and were predominantly detected within necrotizing lesions in lung and occasionally in lesions affecting liver and trachea. Interestingly, the lung of one animal without obvious necrotizing pulmonary lesions revealed positive hybridization results in the lumen of one pulmonary blood vessel. Two negative controls, including one bacteriologically S. ornithocola-negative great tit and a cattle egret (Bubulcus ibis) suffering from salmonellosis, did not yield positive signals, indicating high sensitivity and specificity of the probe used. This is the first time that S. ornithocola has been clearly identified within necrotizing lesions in deceased tits. Although Koch's postulates have yet to be fulfilled, positive hybridization signals in association with detectable lesions are considered as further and strong evidence of the significant contribution of S. ornithocola to the several episodes of tit mortality recorded in Germany.

Detection and molecular characterization of astro and bocaviruses in dogs in Minnesota

Canine astrovirus (CAstV) and canine bocavirus (CBoV) are involved in cases of mild, and sometimes severe, gastroenteritis in dogs. Fecal samples from two dead dogs with gastroenteritis were received at the University of Minnesota Veterinary Diagnostic Laboratory to determine the cause of death. Small round viruses of 20-35 nm diameter were observed by negative contrast electron microscopy. The samples were subjected to Illumina MiSeq sequencing. Both samples were strongly positive for CAstV; all viral reads were related to CAstV. In addition, sample number 1 had a few reads of CBoV. Two complete sequences of CAstV were identified (6625 and 6627 nt in length) with 95% nt identity. RT-PCR and PCR were used to confirm CAstV and CBoV infections in successive samples of canine gastroenteritis. Sanger sequencing was done on nucleic acids from positive samples. Of a total of ten samples, CAstV and CBoV infections were confirmed in six and eight animals, respectively. Four animals had mixed infection with both viruses. All sequences of ORF1b gene of CAstVs showed closest clusters in phylogenetic tree with 96-100% nucleotide and amino acids identity. On the other hand, identity between VP2 gene of different CBoV strains in this study ranged from 93%- 100%. All strains were located close to each other except the divergent MT078234 strain, which was arranged in a separate branch and was closer to reference strain JN648103/USA/2010. This study highlights the importance of electron microscopy and next generation sequencing for early detection and characterization of viruses associated with dog gastroenteritis.

Identification and characterization of a novel bocaparvovirus in tufted deer (Elaphodus cephalophus) in China

We used viral metagenomics and next-generation sequencing to identify a novel strain of bocaparvovirus in the intestinal tract of tufted deer (Elaphodus cephalophus), tentatively named "Elaphodus cephalophus bocaparvovirus" (ECBOV). A nearly complete genome sequence of 5,354 nucleotides was obtained, which had the typical genome organization and protein motifs of a bocaparvovirus. Sequence comparisons and phylogenetic analysis revealed that ECBOV may be a new ungulate bocaparvovirus. The identification and characterization of viruses in wildlife will facilitate our understanding of genetic evolution and cross-species transmission and thus further reduce the potential threat to human and animal health.

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.

First detection of feline bocaparvovirus 2 and feline chaphamaparvovirus in healthy cats in Turkey

The pet cat’s population and the number of viruses that infect them are increasing worldwide. Recently, feline chaphamaparvovirus (FeChPV, also called fechavirus) and feline bocaparvovirus (FBoV) infections, which are novel parvovirus species, have been reported in cats from different geographic regions. Here, we investigated FBoV 1–3 and FeChPVs in healthy cats in Turkey using PCR, where nuclear phosphoprotein 1 (NP1) is targeted for FBoV and NP for FeChPV. For this purpose, oropharygeal swabs were obtained from 70 healthy cats with different housing status from June 15 to December 1, 2020. After PCR screening tests, six out of 70 cats (5/47 shelter cats; 1/23 domestic cats) were found to be positive for FBOV, while two were positive for FeChPV (1/47 shelter cats; 1/23 domestic cats). No cat was found in which both viruses were detected. The nucleotide (nt) sequence comparison in the 310 base pair (bp) NP gene of the two FeChPVs identified in this study shared a high identity with each other (95.0% nt and 99% aa identities) and with previously reported FeChPVs (92.4–97.1% nt and 98.1–99.0% aa identities), including 313R/2019/ITA, 49E/2019/ITA, VRI_849, 284R/2019/ITA, and IDEXX-1. Here, the near-full length (1489 nt, 495 amino acids-aa) of the VP2 gene of the FechaV/Tur-2020/68 isolate obtained from the study was also sequenced. The nt and aa identity ratio of this isolate with other FeChPVs was 98.0–98.5%-96–96.5%, respectively. Sequences of the 465 bp NP1 gene of the six Turkish FBoV strains shared high identities with each other (99.6–100% nt and 99.3–100% aa identities) and with those of FBoV-2 strains (97.8–99.1% nt and 98.0–100% aa identities), including 16SY0701, 17CC0505-BoV2, HFXA-6, and POR1. All FBoVs detected in this study were classified as genotype 2, similar to the study conducted in Japan and Portugal. Here, the NS1 (partial), NP1, VP1 and VP2 gene of the FBoV-2/TUR/2020–14 strain obtained from the study were also sequenced and the nt and aa sequences showed high identities to the above-mentioned FBoV-2 strain/isolates (> 96%, except for the aa ratio of strain 16SY0701). In conclusion, this study shows that FBoV and FeChPV are present in healthy cats in Turkey, and these viruses can be detected from oropharyngeal swabs. Our findings contribute to further investigation of the prevalence, genotype distribution, and genetic diversity of Turkish FBoVs and FeChPVs, adding to the molecular epidemiology of FBoV and FeChPVs worldwide.

Canine bocavirus-2 infection and its possible association with encephalopathy in domestic dogs

Canine bocaviruses (CBoVs) have been recognized as pathogens associated with intestinal diseases. Hematogenous spreading caused by CBoV has been documented and may potentiate the virus entry across the blood-brain barrier to initiate a brain infection. This study focused attention on CBoV detection in cases of encepahlopathy and attempted to determine its viral localization. A total of 107 dog brains that histologically exhibited encephalopathy (ED) were investigated for the presence of CBoVs using polymerase chain reaction (PCR). Thirty-three histologically normal brain samples from dogs were used as a control group (CD). CBoV-2 was detected in 15 ED dogs (14.02%) but not in CD dogs (p = 0.02), while no CBoV-1 and -3 were detected. Among the CBoV-2 positive dogs, brain histological changes were characterized by nonsuppurative encephalitis, with inclusion body-like materials in some brains. In situ hybridization (ISH) and transmission electron microscopy (TEM) confirmed the presence of CBoV-2 viral particles in glial cells, supporting neurotropism of this virus. ISH signals were also detected in the intestines, lymphoid organs, and the heart, suggesting both enteral and parenteral infections of this virus. Whole genome characterization and evolutionary analysis revealed genetic diversity of CBoV-2 sequences and it was varying among the different countries where the virus was detected. This study points to a possible association of CBoV-2 with encephalopathy in dogs. It also highlights the genetic diversity and cellular tropism of this virus.

Porcine Bocavirus: A 10-Year History since Its Discovery

Porcine bocavirus (PBoV) is a single-stranded DNA virus, belongs to the genus Bocaparvovirus of family Parvoviridae. It was discovered along with porcine circovirus 2 (PCV 2) and torque tenovirus (TTV) in the lymph nodes of pigs suffering from postweaning multisystemic wasting syndrome (PMWS) in Sweden in 2009. PBoV has been reported throughout the world, mostly in weaning piglets, and has a broad range of tissue tropism. Since PBoV is prevalent in healthy as well as clinically infected pigs and is mostly associated with coinfection with other viruses, the pathogenic nature of PBoV is still unclear. Currently, there are no cell lines available for the study of PBoV, and animal model experiments have not been described. This review summarizes the current state of knowledge about PBoV, including the epidemiology, evolution analysis, detection methods, pathogenesis and public health concerns.

Bovine Babesiosis Diagnosed in Formalin-Fixed, Paraffin-Embedded Tissues by Using In Situ Hybridization

Bovine babesiosis, caused by Babesia divergens, is in general a rare disease in Europe. Nonetheless, local outbreaks can cause severe economic damage, and postmortem identification represents a diagnostic challenge. During a recent outbreak in May 2018 in northern Germany, 21 animals of a herd of 150 cattle died within 40 days having had clinical signs of fever and hemoglobinuria. Gross examination of 4 of the 21 deceased animals revealed a tick infestation, jaundice, and dark brown staining of urine and kidneys. Histologically, there were iron-positive deposits, hyperplasia of the red pulp of the spleen, and centrilobular necrosis of hepatocytes. In several locations, small basophilic granules suggestive of intraerythrocytic parasites were visible in hematoxylin-eosin- and Giemsa-stained sections. Peripheral blood smears from a living cow from the herd and polymerase chain reaction (PCR) of feeding ticks revealed B. divergens infection. In situ hybridization (ISH) was applied on formalin-fixed, paraffin-embedded (FFPE) tissue of the necropsied cattle to confirm babesiosis in these animals postmortem. Digoxigenin-labeled DNA probes were generated based on a specific nucleotide sequence for B. divergens, obtained by PCR and sequencing of DNA isolates from infected Ixodes ricinus ticks from deceased cattle. ISH using these probes allowed postmortem diagnosis of B. divergens infection in routinely fixed FFPE tissues.

Feline bocavirus-1 associated with outbreaks of hemorrhagic enteritis in household cats: potential first evidence of a pathological role, viral tropism and natural genetic recombination

Feline bocavirus-1 (FBoV-1) was identified in cats from different households with hemorrhagic enteritis during outbreaks of an unusual clinical presentation of feline panleukopenia virus (FPLV) in Thailand. Use of polymerase chain reaction revealed the presence of the FBoV-1 DNA in several tissues, suggesting hematogenous viremia, with the viral nucleic acid, detected by in situ hybridization (ISH), was localized in intestinal cells and vascular endothelium of intestinal mucosa and serosa, and in necrosis areas primarily in various lymph nodes while FPLV-immunohistochemical analysis revealed viral localization only in cryptal cells, neurons, and limited to leukocytes in the mesenteric lymph node. Full-length coding genome analysis of the Thai FBoV-1 strains isolated from moribund cats revealed three distinct strains with a high between-strain genetic diversity, while genetic recombination in one of the three FBoV-1 strains within the NS1 gene. This is the first report identifying natural genetic recombination of the FBoV-1 and describing the pathology and viral tropism of FBoV-1 infection in cats. Although the role of FBoV-1 associated with systemic infection of these cats remained undetermined, a contributory role of enteric infection of FBoV-1 is possible. Synergistic effects of dual infection with FPLV and FBoV-1 are hypothesized, suggesting more likely severe clinical presentations.

Effect of Geographic Isolation on the Nasal Virome of Indigenous Children

The influence of living in small remote villages on the diversity of viruses in the nasal mucosa was investigated in three Colombian villages with very different levels of geographic isolation. Metagenomic analysis was used to characterize viral nucleic acids in nasal swabs from 63 apparently healthy young children. Sequences from human virus members of the families Anelloviridae, Papillomaviridae, Picornaviridae, Herpesviridae, Polyomaviridae, Adenoviridae, and Paramyxoviridae were detected in decreasing proportions of children. The number of papillomavirus infections detected was greater among Hispanic children most exposed to outside contacts, while anellovirus infections were more common in the isolated indigenous villages. The diversity of the other human viruses detected did not differ among the villages. Closely related variants of rhinovirus A or B were identified in 2 to 4 children from each village, reflecting ongoing transmission clusters. Genomes of viruses not currently known to infect humans, including members of the families Parvoviridae, Partitiviridae, Dicistroviridae, and Iflaviridae and circular Rep-encoding single-stranded DNA (CRESS-DNA) virus, were also detected in nasal swabs, possibly reflecting environmental contamination from insect, fungal, or unknown sources. Despite the high levels of geographic and cultural isolation, the overall diversity of human viruses in the nasal passages of children was not reduced in highly isolated indigenous villages, indicating ongoing exposure to globally circulating viruses.IMPORTANCE Extreme geographic and cultural isolation can still be found in some indigenous South American villages. Such isolation may be expected to limit the introduction of otherwise common and widely distributed viruses. Very small population sizes may also result in rapid local viral extinction due to a lack of seronegative subjects to maintain transmission chains for rapidly cleared viruses. We compared the viruses in the nasal passages of young children in three villages with increasing levels of geographic isolation. We found that isolation did not reduce the overall diversity of viral infections. Multiple infections with nearly identical rhinoviruses could be detected within each village, likely reflecting recent viral introductions and transmission clusters among epidemiologically linked members of these very small communities. We conclude that, despite their geographic isolation, remote indigenous villages show evidence of ongoing exposure to globally circulating viruses.

Complete genome sequence analysis of canine bocavirus 1 identified for the first time in domestic cats

In this study, we investigated the presence of canine bocaviruses (CBoVs) in fecal samples from 105 cats with diarrhea and 92 asymptomatic cats in northeast China. One fecal sample, 17CC0312, collected from an asymptomatic cat, was found to be positive for canine bocavirus 1 (CBoV1). The nearly complete genome of this virus was cloned and sequenced. The viral genome was 5,069 nucleotides (nt) in length and combined four open reading frames (ORFs) in the order 5′-NS1-ORF4-NP1-VP1/VP2-3′. The 17CC0312 virus shared more than 90.3% nucleotide sequence identity with CBoV1 reference sequences and was placed within the CBoV1 group in a phylogenetic tree based on complete genome sequences. Further phylogenetic analysis based on the deduced amino acid sequence of the VP2 gene showed that this feline CBoV1 strain belongs to CBoV1 lineage 3. These data provide the first molecular evidence of the presence of CBoV1 in a domestic cat and suggest that cats might be carriers of CBoV1.

Development of an in-situ hybridization assay using riboprobes for detection of viral haemorrhagic septicemia virus (VHSV) mRNAs in a cell culture model

An in situ hybridization (RNA-ISH) assay has been developed and optimized to detect viral haemorrhagic septicemia virus (VHSV), an OIE listed piscine rhabdovirus, in infected fish cells using fathead minnow (FHM) as a model cell line. Two antisense riboprobes (RNA probes) targeting viral transcripts from a fragment of nucleoprotein (N) and glycoprotein (G) genes were generated by reverse transcription polymerase chain reaction (RT-PCR) using VHSV specific primers followed by a transcription reaction in the presence of digoxigenin dUTP. The synthesized RNA probes were able to detect viral mRNAs in formalin fixed VHSV infected FHM cells at different time points post inoculation (pi). To correlate the signal intensity, a time dependent quantitation of the viral mRNA transcript and infectivity titer was done by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and 50% tissue culture infectivity dose (TCID₅₀), respectively, from the infected cells and culture supernatants. Further, we compared the diagnostic sensitivity of ISH assay with immunocytochemistry (ICC). Both the riboprobes used in the ISH assay detected VHSV as early as 6 hpi in the FHM cells inoculated with a multiplicity of infection (moi) of 2. Also, the signal detection in ISH was at an early stage in comparison to ICC, wherein, signal was first detected at 12 hpi. Our results clearly highlight that current ISH assay can be of value as a diagnostic tool to localize and detect VHSV in conjunction with conventional virus isolation in cell culture.

Detection and genetic characterization of feline bocavirus in Northeast China

Background

Bocaviruses have been reported to cause respiratory tract infection and gastroenteritis in most animal species. In cats, different genotype bocaviruses have been identified in USA, Japan, Hong Kong and Portugal. However, the clear relationship between the clinical symptoms and FBoV infection is unknown, and the prevalence of FBoV and the distribution of FBoV genotypes in China are still unclear.

Results

In this study, 197 fecal samples from cats with diarrhea (n = 105) and normal cats (n = 92) were collected in different regions between January 2016 and November 2017 and investigated using PCR targeting different FBoV genotypes. Screening results showed that 51 of 197 samples (25.9%) were positive for FBoV, and a higher positive rate was observed in cats with diarrhea (33.3%, 35/105) than in normal cats (17.4%, 16/92). Of these FBoV-positive samples, 35 were identified as FBoV-1, 12 as FBoV-2 and 4 as coinfection of FBoV-1 and FBoV-2. A phylogenetic analysis based on partial NS1 gene indicated that 24 sequences from randomly selected FBoV-positive samples were divided into 2 different FBoV groups: FBoV-1 and FBoV-2. Furthermore, 6 strains were randomly selected, and the complete genome was sequenced and analyzed. These strains exhibited the typical genome organization of bocavirus and were closely related to FBoV. Two FBoV-2 identified strains shared high homologies with FBoV-2 reference strains based on the complete genome and entire encoding gene, but lower identities were exhibited in the NP1 and VP1 regions for the other 4 FBoV-1 identified strains compared with FBoV-1 reference strains.

Conclusion

These findings demonstrate that genetically diverse FBoV-1 and FBoV-2 widely circulate in cats in Northeast China and that FBoV-1 is more prevalent. The high prevalence of FBoV in cats with diarrhea symptoms suggests that FBoV infection may be associated with diarrhea in cats.

Electronic supplementary material

The online version of this article (10.1186/s12985-018-1034-3) contains supplementary material, which is available to authorized users.

Comparison of Different In Situ Hybridization Techniques for the Detection of Various RNA and DNA Viruses

In situ hybridization (ISH) is a technique to determine potential correlations between viruses and lesions. The aim of the study was to compare ISH techniques for the detection of various viruses in different tissues. Tested RNA viruses include atypical porcine pestivirus (APPV) in the cerebellum of pigs, equine and bovine hepacivirus (EqHV, BovHepV) in the liver of horses and cattle, respectively, and Schmallenberg virus (SBV) in the cerebrum of goats. Examined DNA viruses comprise canine bocavirus 2 (CBoV-2) in the intestine of dogs, porcine bocavirus (PBoV) in the spinal cord of pigs and porcine circovirus 2 (PCV-2) in cerebrum, lymph node, and lung of pigs. ISH with self-designed digoxigenin-labelled RNA probes revealed a positive signal for SBV, CBoV-2, and PCV-2, whereas it was lacking for APPV, BovHepV, EqHV, and PBoV. Commercially produced digoxigenin-labelled DNA probes detected CBoV-2 and PCV-2, but failed to detect PBoV. ISH with a commercially available fluorescent ISH (FISH)-RNA probe mix identified nucleic acids of all tested viruses. The detection rate and the cell-associated positive area using the FISH-RNA probe mix was highest compared to the results using other probes and protocols, representing a major benefit of this method. Nevertheless, there are differences in costs and procedure time.

Novel canine circovirus strains from Thailand: Evidence for genetic recombination

Canine circoviruses (CanineCV's), belonging to the genus Circovirus of the Circoviridae family, were detected by next generation sequencing in samples from Thai dogs with respiratory symptoms. Genetic characterization and phylogenetic analysis of nearly complete CanineCV genomes suggested that natural recombination had occurred among different lineages of CanineCV's. Similarity plot and bootscaning analyses indicated that American and Chinese viruses had served as major and minor parental viruses, respectively. Positions of recombination breakpoints were estimated using maximum-likelihood frameworks with statistical significant testing. The putative recombination event was located in the Replicase gene, intersecting with open reading frame-3. Analysis of nucleotide changes confirmed the origin of the recombination event. This is the first description of naturally occurring recombinant CanineCV's that have resulted in the circulation of newly emerging CanineCV 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.

New viruses associated with canine gastroenteritis

A number of novel viruses have been associated with canine gastroenteritis in recent years, from viral families as diverse as Caliciviridae and Picornaviridae to Parvoviridae and Circoviridae. The ability of many of these viruses to cause disease is uncertain, but epidemiological studies are continually adding to our knowledge of these potential pathogens. This review presents a summary of the latest research and current understanding of novel viruses associated with canine gastroenteritis.

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.

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.

Pathological findings in the red fox (Vulpes vulpes), stone marten (Martes foina) and raccoon dog (Nyctereutes procyonoides), with special emphasis on infectious and zoonotic agents in Northern Germany

Anthropogenic landscape changes contributed to the reduction of availability of habitats to wild animals. Hence, the presence of wild terrestrial carnivores in urban and peri-urban sites has increased considerably over the years implying an increased risk of interspecies spillover of infectious diseases and the transmission of zoonoses. The present study provides a detailed characterisation of the health status of the red fox (Vulpes vulpes), stone marten (Martes foina) and raccoon dog (Nyctereutes procyonoides) in their natural rural and peri-urban habitats in Schleswig-Holstein, Germany between November 2013 and January 2016 with focus on zoonoses and infectious diseases that are potentially threatening to other wildlife or domestic animal species. 79 red foxes, 17 stone martens and 10 raccoon dogs were collected from traps or hunts. In order to detect morphological changes and potential infectious diseases, necropsy and pathohistological work-up was performed. Additionally, in selected animals immunohistochemistry (influenza A virus, parvovirus, feline leukemia virus, Borna disease virus, tick-borne encephalitis, canine adenovirus, Neospora caninum, Toxoplasma gondii and Listeria monocytogenes), next-generation sequencing, polymerase chain reaction (fox circovirus) and serum-neutralisation analysis (canine distemper virus) were performed. Furthermore, all animals were screened for fox rabies virus (immunofluorescence), canine distemper virus (immunohistochemistry) and Aujeszky's disease (virus cultivation). The most important findings included encephalitis (n = 16) and pneumonia (n = 20). None of the investigations revealed a specific cause for the observed morphological alterations except for one animal with an elevated serum titer of 1:160 for canine distemper. Animals displayed macroscopically and/or histopathologically detectable infections with parasites, including Taenia sp., Toxocara sp. and Alaria alata. In summary, wildlife predators carry zoonotic parasitic disease and suffer from inflammatory diseases of yet unknown etiology, possibly bearing infectious potential for other animal species and humans. This study highlights the value of monitoring terrestrial wildlife following the "One Health" notion, to estimate the incidence and the possible spread of zoonotic pathogens and to avoid animal to animal spillover as well as transmission to humans.

[Prevalence of Dog circovirus in healthy and diarrhoeic dogs]

OBJECTIVE

In 2012, a Dog circovirus (DogCV) was discovered in the USA, which was followed by further descriptions of the virus in the USA, Italy and Germany. The present study is the first to examine the prevalence of DogCV in faeces of dogs from Germany and other European countries.

MATERIAL AND METHODS

Faecal samples from 184 dogs with diarrhoea and from 82 clinically healthy dogs (control group) were analysed for the presence of DogCV by PCR. Furthermore, the detection of parvovirus, coronavirus, Giardia and Cryptosporidium was performed in all samples.

RESULTS

In the group of dogs with diarrhoea the prevalence of DogCV was 20.1% (37/184), in the healthy control group it was 7.3% (6/82). Therefore, the virus could be detected significantly more frequently in dogs with diarrhoea. The detection frequency of DogCV is comparable with those of the other tested pathogens. In approximately 50% of the DogCV-positive dogs, infections with other enteropathogenic organisms were diagnosed.

CONCLUSION AND CLINICAL RELEVANCE

The role of co-infection in the pathogenesis of the disease remains unclear, but there appears to be an association between co-infection and disease severity. Evidence of DogCV in clinically healthy dogs appears important for the epidemiology and raises questions about its pathogenicity. Further studies are needed to clarify questions regarding the pathogenesis, causal relevance and possible interference by other diarrhoeal pathogens. Nevertheless, the results of this study are an important indication that DogCV should be considered as a differential diagnosis in dogs with diarrhoea.

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.

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.

Co-Circulation of the Rare CPV-2c with Unique Gln370Arg Substitution, New CPV-2b with Unique Thr440Ala Substitution, and New CPV-2a with High Prevalence and Variation in Heilongjiang Province, Northeast China

To trace evolution of canine parvovirus-2 (CPV-2), a total of 201 stool samples were collected from dogs with diarrhea in Heilongjiang province of northeast China from May 2014 to April 2015. The presence of CPV-2 in the samples was determined by PCR amplification of the VP2 gene (568 bp) of CPV-2. The results revealed that 95 samples (47.26%) were positive for CPV-2, and they showed 98.8%–100% nucleotide identity and 97.6%–100% amino acid identity. Of 95 CPV-2-positive samples, types new2a (Ser297Ala), new2b (Ser297Ala), and 2c accounted for 64.21%, 21.05%, and 14.74%, respectively. The positive rate of CPV-2 and the distribution of the new2a, new2b and 2c types exhibited differences among regions, seasons, and ages. Immunized dogs accounted for 48.42% of 95 CPV-2-positive samples. Coinfections with canine coronavirus, canine kobuvirus, and canine bocavirus were identified. Phylogenetic analysis revealed that the identified new2a, new2b, and CPV-2c strains in our study exhibited a close relationship with most of the CPV-2 strains from China; type new2a strains exhibited high variability, forming three subgroups; type new2b and CPV-2c strains formed one group with reference strains from China. Of 95 CPV-2 strains, Tyr324Ile and Thr440Ala substitutions accounted for 100% and 64.21%, respectively; all type new2b strains exhibited the Thr440Ala substitution, while the unique Gln370Arg substitution was found in all type 2c strains. Recombination analysis using entire VP2 gene indicated possible recombination events between the identified CPV-2 strains and reference strains from China. Our data revealed the co-circulation of new CPV-2a, new CPV-2b, and rare CPV-2c, as well as potential recombination events among Chinese CPV-2 strains.

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.

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.

Human bocavirus infection as a cause of severe acute respiratory tract infection in children

In 2005 human bocavirus (HBoV) was discovered in respiratory tract samples of children. The role of HBoV as the single causative agent for respiratory tract infections remains unclear. Detection of HBoV in children with respiratory disease is frequently in combination with other viruses or bacteria. We set up an algorithm to study whether HBoV alone can cause severe acute respiratory tract infection (SARI) in children. The algorithm was developed to exclude cases with no other likely cause than HBoV for the need for admission to the paediatric intensive care unit (PICU) with SARI. We searched for other viruses by next-generation sequencing (NGS) in these cases and studied their HBoV viral loads. To benchmark our algorithm, the same was applied to respiratory syncytial virus (RSV)-positive patients. From our total group of 990 patients who tested positive for a respiratory virus by means of RT-PCR, HBoV and RSV were detected in 178 and 366 children admitted to our hospital. Forty-nine HBoV-positive patients and 72 RSV-positive patients were admitted to the PICU. We found seven single HBoV-infected cases with SARI admitted to PICU (7/49, 14%). They had no other detectable virus by NGS. They had much higher HBoV loads than other patients positive for HBoV. We identified 14 RSV-infected SARI patients with a single RSV infection (14/72, 19%). We conclude that our study provides strong support that HBoV can cause SARI in children in the absence of viral and bacterial co-infections.