Avian influenza outbreaks of poultry in high risk areas of Thailand, June-December 2005

Abstract

There were 848 suspected and 188 confirmed Avian Influenza (AI) in poultry flocks in Thailand in 2005. Between June to December 2005, the Suphanburi province reported the highest number of AI confirmed flocks. This chapter is an account of the outbreak with a description of risk factors and recommended preventive measures in poultry farming. Our case definition of a suspected flock is a poultry flock with abnormal deaths of more than 10% within one day or more than 40% within three days, while an AI confirmed flock is a suspected flock with laboratory confirmation. We interviewed poultry owners and conducted a case control study in the Suphanburi province in which 25 of 79 reported cases of suspected flocks were confirmed between June to December 2005. Most of the confirmed flocks (about 64%) were backyard native chickens. The percentage of deaths in the first three days for backyard native chicken and free-grazing duck flocks were 19% compared to 0.46% for layer and broiler flocks. A number of risk factors, such as contact with waterfowl or proximity to feeding areas, was associated with the AI infection. The association between the number of poultry population and that of AI confirmed flocks by areas was also explored. Other than improving bio-security in poultry farms, some practical recommendations including how to deal with dead birds and how to protect poultry from neighboring infected poultry should be communicated especially to backyard chicken owners.