Surveillance on prevalence of influenza A/H5 virus at live bird market in Ha Noi in 2016

Abstract

Avian influenza surveillance is always a matter that should be paid special attention due to the infection and transmission of avian influenza A/H5 virus are very complicated. In this study we conducted surveillance on prevalence of influenza A/H5 virus in 4 live poultry markets. The swab samples were collected from the poultry, including chickens and ducks with 5 swab samples were pooled into a tube. The swab samples were used to isolate avian influenza virus on embryonated eggs. The identified viruses were analyzed for detection of influenza A by Realtime RT-PCR. The positive samples for influenza type A was further subtyped for H5 by Realtime RT-PCR. The studied results showed that from 900 samples collected in 2016, 105 isolates were successfully determined, of which 92 samples were positive with  influenza A virus, of which 34 samples were derived from chickens and 58 samples were derived from ducks. Four samples were positive with H5, including 3 samples of H5N6 and one sample of H5N1. All positive samples with influenza H5 virus were derived from ducks in the provinces surrounding Ha Noi. The occurrence of H5 virus in the market demonstrated that trading the live poultry was a risky factor for H5 virus entering in Ha Noi, warning that H5 virus could be transmitted to human. The successful isolation for the influenza type A virus in general and influenza H5 virus in particular from the live bird markets should be emphasized that continuous surveillance on influenza A/H5 virus is necessary