Assessment of biosecurity practices and risk factors for avian influenza outbreaks in commercial poultry farms in Bangladesh.

High pathogenicity avian influenza (HPAI) continues to be a major threat to poultry production in Bangladesh, where poultry is a primary source of affordable protein and outbreaks also pose zoonotic risks to humans. We conducted a cross-sectional study in 331 commercial broiler, layer, and Sonali poultry farms to evaluate biosecurity and farm management practices across different poultry production systems in relation to government-recommended biosecurity guidelines, and to identify risk factors associated with avian influenza (AI) outbreaks, as well as to assist in mitigating AI outbreak risks and improving disease prevention in poultry farms. We found that 93.4% of farms were in residential areas and 68.8% of the farms were near waterbodies. A significant number of farms had access to domestic and wild animals, with limited implementation of disinfection and hygiene practices. Overall, most farms did not fully comply with government suggested standard biosecurity and good farm management guidelines. In total, 51 (15.4%) farms reported AI outbreaks with the highest proportion in layer farms (29.1%), followed by broiler (10.6%) and Sonali (7.8%). AI outbreaks were significantly associated with outbreak history on nearby farms, farmers or workers visiting other farms, and farm management by workers or multiple individuals rather than owners. Veterinarian visits were also found to be associated with outbreaks on farms, which may reflect reporting bias rather than causality. Our findings underscore that substantial gaps in biosecurity compliance remain widespread across all farm types. We recommend strengthening biosecurity protocols, addressing environmental risks, and providing comprehensive training programs for farmers to control AI spread, prevent future outbreaks, and ultimately safeguard both poultry and public health.