Characterization of canine coronavirus spread among domestic dogs inVietnam

[摘要] Canine coronavirus (CCoV) is an important pathogen that causes enteritis in dogs, butthere is no information on CCoV infection in Vietnam. To examine the prevalence of CCoVinfection among Vietnamese dogs, 201 serum samples were analyzed by virus-neutralization(VN) test. The results showed that antibody against CCoV-II was present in 87 dogs(43.3%). To detect genes of CCoV, fecal samples collected from 30 diarrheic and 50 healthydogs were examinated by RT-PCR, confirming that 2 diarrheic dogs and 5 healthy dogs werepositive for CCoV. Nucleotide sequences of N-terminal region of spike (S)gene indicated that CCoV strains were divided into two subgenotypes, CCoV-IIa and -IIb,respectively. Furthemore, we succeeded in isolating CCoV/dog/HCM47/2015, the isolate wasplaque-purified three times, and 3’-terminal one-third of the genome was analyzed.Interestingly, the plaque-purified virus had a large deletion in ORF3abc and E genes(1,165 nt), and a short deletion in ORF7b gene (60 nt), suggesting that these regions arenot necessary for in vitro replication of CCoV. Next, the antigenicitybetween the isolated CCoV-IIb and the other CCoV-IIa was compared by VN test, revealingthat antigenicty of the isolated CCoV is equal or higher than that of the other CCoV. Insummary, two subgenotypes of CCoV-II are spreading among Vietnamese dogs. The isolatedvirus with a large deletion after in vitro passage may be useful for thedevelopment of vaccine, owing to its antigenicity and efficient viral growth invitro.

[学科分类] 兽医学

[关键词] coronavirus;dog;genotype