Detection and molecular characterization of canine circovirus circulating in northeastern China during 2014–2016

Abstract

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.

First detection and full genomic analysis of Canine Circovirus in CPV-2 infected dogs in Colombia, South America

“…The phylogenetic relationships based on the nucleotide alignment of complete genome sequences inferred by distances (neighbor joining) and characters (maximum likelihood) approaches exhibited trees with the same topology (data no shown). As previously reported 21 , we confirmed that worldwide reported CanineCV strains were separated into four distinct genotypes (previously denoted as CanineCV-1 to -4) with a greater majority of sequences with a Chinese origin and a paraphyletic distribution of each subclade. Due to the current distribution of new CanineCV sequences, we propose to designate different clades according to the geographical distribution (Genotypes).…”

“…Later on, the virus was reported in Argentina in an outbreak of fatal gastroenteritis in www.nature.com/scientificreports/ dogs 25 , which was detected in multiple organs of the infected animals (pancreas, liver, kidney, lung, lymph nodes, spleen and large intestine). Since Kapoor et al, reported the detection of CanineCV for the first time in the serum of healthy dogs in the USA 1 , several studies have demonstrated the high circulation of CanineCV in different canine populations around world, with prevalences (or diagnostic rates) from 1 to 33% of the evaluated samples and it has been reported in almost all continents 20,21,23 . Our results strongly agree with the frequencies reported for northern China where the prevalence of CanineCV among diarrheic dogs was 15.6% 21 .…”

“…The critical role of CanineCV as single diarrheagenic agent has been extensively discussed and its pathogenicity has not been clarified yet. The CanineCV has been detected in both symptomatic and asymptomatic dogs 21,25,34 , and only vasculitis and histiocytic inflammation have been associated in some dogs 2 . CanineCV have not been involved as the primary causative agent of the acute haemorrhagic diarrhoea syndrome in dogs, but might play an important role as a negative co-factor in the disease outcome in dogs with CPV-2 infection 34 .…”

“…The best-fit model of nucleotide substitution was selected (GTR + G + I) and Maximum-likelihood and neighbor joining trees with a bootstrap value of 1000 were inferred. Phylogenetic analysis was inferred as previously reported, in order to characterize the CanineCV into four distinct genotypes (denoted as CanineCV-1 to -4) 21 . All Phylogenetic analysis were performed by using MEGA 7.0 for Windows.…”

“…It is well known that gastrointestinal disorders in canines are one of the most common diseases reported in clinics of companion animal and that these disease can be caused by a number of synergistic viral, bacterial and parasitic pathogens 20 . Recent molecular surveys have proposed the role of CanineCV not only as a causative agent but also it might play a role as a co-pathogen in the development of gastrointestinal disorders, mainly acting in synergism with other enteric viruses such as Canine Parvovirus-2 (CPV-2) [20][21][22][23] .…”