Detection of kobuvirus RNA in Japanese domestic dogs

SOMA, Takehisa; MATSUBAYASHI, Makoto; SASAI, Kazumi

In the present study, kobuvirus RNA was detected at a high rate in the dog fecal samples. As a result of 3D nucleotide sequence analysis, it was revealed that the virus had a very high homology with previously reported CaKoV, suggesting that CaKoV has been transmitted among Japanese dogs. Generally, infectious viral diseases tend to be epidemic during the juvenile period [25, 26, 32] , and we observed a similar tendency for CaKoV in the present study. Surprisingly, however, the frequency of viral RNA detection was confined in the dogs four months old or younger and was never found in those older than five months. These findings indicate that dogs have a strong age-dependent resistance to CaKoV and that the dog infected with CaKoV in the past has a high resistance to reinfection. Unfortunately, since the kenneled dogs of this study were aged 1-3 months, the positivity could not be analyzed by age. Furthermore, our findings showed a high rate of detection of viral RNA in kennels, similar to the finding of Choi et al. [4] . Thus, we speculated that CaKoV prevalence is confined to multi-dog environments.