Anti-Parvovirus VP2 monoclonal antibody, clone 2D21

Parvoviruses are a diverse group of viruses that are capable of infecting a wide range of animals. In this study, we report the discovery of a novel parvovirus, tilapia parvovirus HMU-HKU, in the fecal samples of crocodiles and intestines of tilapia in Hainan Province, China. The novel parvovirus was firstly identified from crocodiles fed with tilapia using next-generation sequencing (NGS). Screening studies revealed that the prevalence of the novel parvovirus in crocodile feces samples fed on tilapia (75-86%) was apparently higher than that in crocodiles fed with chicken (4%). Further studies revealed that the prevalence of the novel parvovirus in tilapia feces samples collected at four areas in Hainan Province was between 40 and 90%. Four stains of the novel parvovirus were identified in this study based on sequence analyses of NS1 and all the four strains were found in tilapia in contrast only two of them were detected in crocodile feces. The nearly full-length genome sequence of the tilapia parvovirus HMU-HKU-1 was determined and showed less than 45.50 and 40.38% amino acid identity with other members of Parvoviridae in NS1 and VP1 genes, respectively. Phylogenetic analysis based on the complete helicase domain amino acid sequences showed that the tilapia parvovirus HMU-HKU-1 formed a relatively independent branch in the newly proposed genus Chaphamaparvovirus in the subfamily Hamaparvovirinae according to the ICTV's most recent taxonomic criteria for Parvoviridae classification. Tilapia parvovirus HMU-HKU-1 likely represented a new species within the new genus Chaphamaparvovirus. The identification of tilapia parvovirus HMU-HKU provides further insight into the viral and genetic diversity of parvoviruses and its infections in tilapia populations need to be evaluated in terms of pathogenicity and production losses in tilapia farming.

Canine circovirus (canine CV) is an etiological agent associated with diarrhea, hemorrhagic gastroenteritis and vasculitis. Although canine CV has been identified and characterized in southern China in recent years, its epidemiology in other regions of China and its precise molecular characteristics have not been examined. In this study, we examined 141 fecal specimens collected from domestic dogs with or without diarrhea in Heilongjiang province, Northeastern China, during 2014 to 2016. A total of 18 out of 141 samples were found to be positive for canine CV by real-time quantitative PCR. In the diarrhea samples, canine CV was detected in coinfections with canine parvovirus 2. More importantly, two different canine CV strains were detected in one sample. Five canine CV genomes were successfully amplified. Sequence analysis showed that there were two unique amino acid changes in the Rep protein (N39S in the K1 strain, and T71A in the XF16 strain). Phylogenetic analysis indicated that canine CV could be divided into four genotypes, and specific nucleotide mutations could be used for confirming the four genotypes. Moreover, recombination analysis revealed that a total of eight recombination events were found in five genomic sequences. Molecular evolution analysis showed that the canine CV has been under purifying selection. This study provides evidence that at least three genotypes of canine CV are co-circulating in China. Continuous epidemiological surveillance is therefore necessary to understand their importance for the evolution of canine CV.