Abstract:[Objective] To learn the prevalence and genotypic diversity of canine coronavirus (CCoV) in healthy and diarrhea dogs in Shandong Province. [Methods] We collected 199 anal swabs from healthy and diarrhea dogs in pet markets, stray dog centers, kennels, and pet hospitals in Shandong Province since 2017. CCoV was detected and genotyped by PCR method, and then the amplified M and S genes were sequenced and analyzed. [Results] Among the 199 anal swabs, 79 were CCoV-positive. The positive rate of CCoV was 40.2% (33/82) in healthy dogs and 39.3% (46/117) in diarrhea dogs. The positive rates of CCoV-Ⅰ and CCoV-Ⅱ were 78.8% (26/33) and 51.5% (17/33) in healthy dogs, and 39.13% (18/46) and 80.4% (37/46) in diarrhea dogs, respectively. CCOV-Ⅰ had the highest single infection rate (48.5%, 16/33) in healthy dogs, while CCoV-Ⅱ had the highest single infection rate (47.8%, 22/46) in diarrhea dogs. The M gene sequences of 48 strains were determined by sequencing analysis. Phylogenetic analysis showed that 11 out of the 12 CCoV-Ⅰ strains were isolated from healthy dogs. Among the 36 CCoV-Ⅱ strains, 7 strains were isolated from healthy dogs and the rest from diarrhea dogs. The 3 strains with whole S gene and obtained from diarrhea dogs all belonged to CCoV-Ⅱ.[Conclusion] The high positive rate of CCoV in the dogs in Shandong Province indicates that the virus is widely prevalent. Multiple infections exist in both healthy and diarrhea dogs. The main prevalent CCoV type is CCoV-I in healthy dogs and CCoV-Ⅱa in diarrhea dogs.
