Isolation 、identification And Phylogenetic Analysie Of H3N2 Subtype Canine Influenza Virus And Sero-epidemiological Investtigation In Guangdong Province

Influenza virus is an important zoonosis virus, including human influenza virus and animal influenza virus. In recent years, there have been continual reports on human infections of influenza viruses from avian-origin and origins of other animals, which pose great threats on human and public health. Since the first report on the emergence of canine influenza virus(CIV) in the USA in 2004. Dog has become a new mammal host of influenza virus,but also poses a threat to human health. So far, two subtype CIVs, H3N8 and H3N2, have entrenched in dogs. The comprehensive epidemiology of influenza infections in dogs in China is unknown, and the pathogenic mechanism of canine influenza virus is also need to be explored. In order to better understand the monitor of infection,spread and epidemic of CIV, serum epidemiology and etiology of H3N2 CIV in Southern China area were studied. The aim was to understand the epidemiology of CIV, and to explore the pathogenic molecular mechanism of canine influenza virus.Epidemiological survey of serum:The collected samples were carried out serum samples from the three dogs: pet market dog, live poultry market dogs and rural dogs collected a total of 764 samples,during the period November 2013 to December2014.Hemagglutination inhibition test(HI) and micro neutralization test(MN) was used to analyze the samples. We found that pet dogs group HI≥1:20 and MN≥1:80 of CIV H3N2 subtype antibody positive rate was17.7%(67/378); rural dog group HI≥1:20 and MN≥1:80of CIV H3N2 subtype antibody positive rate was 15.0%(28/216); live poultry market transactions in dogs HI≥1:20 and MN≥1:80 of CIV H3N2 subtype antibody positive rate for 13.5%( 23/170). The overall positive rate was 15.4%(118/764).There was also evidence that pet dogs infected with canine influenza virus have a relatively large risk. The live bird markets and rural dogs dogs is play a role in the spread of influenza viruses.Isolation and identification of virus : According to the clinical symptoms of dogs infected with influenza virus, a total of 17 nasal swab samples were collected from 24 pet hospitals in Guangzhou City to analysis the characteristics of Guangzhou area epidemic strains.One H3N2 subtype CIV strain were successfully separated, Temporarily named as:A/canine/Guangdong/10/2014(H3N2). the eight fragments were input the tool genotype to carry out restructuring and identification. The analysis showed that the virus was a non recombinant H3N2 avian influenza virus subtype.Through Mega 5.0 analysis software,each gene in the strains H3N2 CIV strains of the open reading frame(ORF) of nucleotide sequences were aligned, and on this basis, rendering system a phylogenetic tree. Genetic analysis showed that the virus was the H3N2 subtype of avian origin, and the evolution of the strains was closed to the isolated from the laboratory before. This shows that the prevalent and spread of H3N2 subtype canine influenza virus is in existence in the canine population of Guangdong province.and there is no large variation. But the H3N2 subtype of influenza virus also needs to continuous tracking and monitoring.