Monitoring of influenza a viruses in Thailand and pathogenicity in dogs and guinea pigs

Abstract

Influenza A virus causes respiratory disease in many species such as birds, horses, pigs, dogs and cats as well as humans. This thesis consists of 5 phases. Phases 1 was monitoring of canine influenza virus infection in Thailand. Phase 2 was determining the intravenous pathogenicity index of Thai canine influenza virus. Phase 3, 4 and 5 were investigating the pathogenicity of canine influenza viruses in dogs, chickens and guinea pigs, respectivly. Our results showed that 0.97% of canine serum samples (9/932) and 1.20% of feline serum sample (1/79) were tested positive for influenza A antibodies by NP-ELISA. Six serum samples (0.64%, 6/932) had HA specific antibodies against pandemic H1N1-2009 by HI assay. Seasonal pattern was also observed. In phase 2, Thai CIV-H3N2 was identified as LPAI based on intravenous pathogenicity test (IVPI), however in phase 3, the intra-species transmission of Thai CIV-H3N2 was confirmed. The CIV-H3N2 infected dogs showed significant clinical signs and H3 specific antibodies. In phase 4, the transmission of Thai CIV-H3N2 in chickens could not be efficiently detected in chickens. In phase 5, the CIV-H3N2 infected guinea pigs and developed mild clinical signs and H3 specific antibodies. In conclusion, our results provided useful information of CIV infection in dogs and cats and the pathogenicity of the Thai CIV-H3N2. These information could be used to develop a strategic plan for influenza prevention and control using One Health approach.