Seroprevalence of avian cause H3N2 canine flu infection disease in pet dogs in Shenzhen, China

Canine influenza virus (CIV) is an emerging pathogen that causes severe and acute respiratory disease in dogs. Canine influenza is caused by two subtypes of influenza. A virus: H3N2 and H3N8. In recent years, surveys of avian origin CIV infection in dogs have been reported worldwide. However, little is known about the prevalence of CIV in pet dogs in China. In the present study, the prevalence of avian origin CIV H3N2 in pet dogs in Shenzhen, Southern China was investigated using the enzyme-linked immunosorbent assay (ELISA) and hemagglutination inhibition (HI) assay. Thirty-one (6.71%) of the 462 serum samples tested were seropositive for avian origin CIV by ELISA. Use of the HI test revealed the presence of anti-H3 antibodies in 28 (6.06%) of 462 serum samples. The prevalence ranged from 4.87% (HI) or 6.19% (ELISA) to 7.41% among dogs of different ages, with high prevalence in pet dogs of 1 to 3 years old, but low prevalence in pet dogs ≤1 year. The seroprevalence in female dogs was 5.21%, and in male dogs it was 7.78% (ELISA) or 6.67% (HI). These findings demonstrated that avian origin canine influenza virus infection is prevalent in pet dogs and can spread rapidly through local dog populations, which indicates its potential for becoming established in pet dogs throughout China.