A cross-sectional descriptive study was conducted to describe the relationship of biological and social factors with the positive sero-conversion against influenza A/H5N1 virus among 607 subjects who traded and slaughtered the poultry in Ha Noi city, Thai Binh and Thanh Hoa provinces for 4 months (September to December, 2011). The data were collected through direct interviews with the structured questionnaire and collected the 3-5ml venous blood for testing by haemagglutination-inhibition test (HAl) and neutralizing micronutrients (MN) techniques. The results showed the positive rate (HAl titres or = 40 and MN titres or = 10) were 6.1 percent, while it was 7.2 percent in Ha Noi city, 5.3 percent in Thai Binh and 4.5 percent in Thanh Hoa provinces. Some factors indicated the direction to increase the risk of influenza A/H5N1 virus infection including the practicing for more than 5 years
poultry exposure 3 hours/day
sell live poultry daily
trafficking sick and/or dead poultry meat
slaughter poultry
does not wear a mask, boots or wash hand regularly while contacting with chickens or geese.