Prevalence of H9N2 subtype Avian influenza viruses in alive poultry selling in some markets in 4 northern provinces, Viet Nam

Abstract

The poultry (chicken and duck) in Viet Nam are the host of H5N1 and H9N2 subtypes avian influenza viruses. We investigated the trading practices for the alive poultry at some markets in Bac Ninh, Thai Nguyen, Hung Yen provinces and Ha Noi City to determine the prevalence of avian influenza virus in the investigating areas. The studied result showed that from 169 positive
poultry samples with avian influenza, the prevalence of H9 was determined to be 20.7% in Pho Hien market (Hung Yen), 27.2% in Ngu Hiep market (Ha Noi), followed by Do market (Bac Ninh) and Ngan market (Hung Yen), the lowest was in Tuc Duyen market (Thai Nguyen) and Ga market (Bac Ninh), the poultry in Ha Vi market (Ha Noi) was identified to be negative with H9. The result of analysing pedigree based on the HA gene sequence revealed that H9 subtype
avian influenza virus strains belonged to sub-clade Y280. The result of analysing pedigree based on the NA gene sequences showed these strains belonged to F98 like branch.