Survey of influenza A viruses in live bird markets in Thailand

Abstract

Live bird markets (LBMs) are places where the birds are sold as pet or poultry meat. LBMs settings usually appear with dense population, multiple species and different sources in order to supply the customers demand. With these conditions, many diseases can transmit and spread within LBMs while some species such as waterfowls and ducks are known as reservoir of influenza A virus entering LBMs everyday. In this study, we conducted a 12 months survey of influenza A virus in 10 LBMs in Thailand, 2009. A total of 5,304 samples from 2,652 animals were collected and tested for influenza A virus. Influenza A viruses subtype H4N6 (n=2), H4N9 (n=1) and H10N3 (n=16) were identified with 0.36% positive (19/5,304). All influenza A isolates were collected from Muscovy ducks in a market located in Bangkok. In Thailand, none of these 3 influenza A subtypes had ever been reported in the country. In this study, H5N1 subtype was not detected which concordant with the report of none influenza A H5N1 outbreak in Thailand during 2009. Our results showed that two influenza A subtypes (H4N6 and H4N9) can be isolated from the same bird at the same collecting time. This result suggested that the reassortment of influenza A virus can occurs in LBMs. In summary, survey of influenza A virus in LBMs is very important and can serves as an early warning system for viral reassortment and spreading of the virus to various avian and mammal species which can cause economical losses and public health problems in the future.