Risk for Infection with Highly Pathogenic Influenza A Virus (H5N1) in Chickens, Hong Kong, 2002

Abstract

We used epidemiologic evaluation, molecular epidemiology, and a case-control study to identify possible risk factors for the spread of highly pathogenic avian influenza A virus (subtype H5N1) in chicken farms during the first quarter of 2002 in Hong Kong. Farm profiles, including stock sources, farm management, and biosecurity measures, were collected from 16 case and 46 control chicken farms by using a pretested questionnaire and personal interviews. The risk for influenza A (H5N1) infection was assessed by using adjusted odds ratios based on multivariate logistic regression analysis. Retail marketing of live poultry was implicated as the main source of exposure to infection on chicken farms in Hong Kong during this period. Infection control measures should be reviewed and upgraded as necessary to reduce the spread of influenza A (H5N1) related to live poultry markets, which are commonplace across Asia.

Incidence of Avian Flu Shocks on Poor Household Livelihoods of Poultry Farmers in Africa

“…Increasing density of poultry is associated with a higher contact rate between susceptible and infected birds and therefore greater risk of spread [29][30][31][32][33][34]. However, no association was found between poultry density and the risk of HPAIV infection in China, suggesting that this unexpected finding was due to a greater proportion of industrialized chicken production at higher poultry densities, with associated higher biosecurity standards and vaccination protocols.…”

Interventions for avian influenza A (H5N1) risk management in live bird market networks

“…Here, poultry traders can mix and potentially transfer the virus either by trading infected poultry or by sharing contaminated equipment. In the absence of effective disinfection, traders may then act as a major source of exposure to infection for farms (13)(14)(15)(16)(17)(18). Once contaminated, some LBMs may even act as viral reservoirs, depending on the poultry management practices of their traders (19,20).…”

Effect of Interventions on Influenza A (H9N2) Isolation in Hong Kong’s Live Poultry Markets, 1999–2005

“…More recently, there has been increasing recognition of their pivotal role in the amplifi cation and maintenance of avian infl uenza viruses, in introduction of infection to poultry farms (3)(4)(5), and in zoonotic transmission of avian infl uenza viruses to humans (2,6). Nevertheless, LPMs proliferate throughout south Asia and Southeast Asia as well as in other parts of the world, including parts of the United States.…”