Risk for infection with highly pathogenic influenza A virus (H5N1) in chickens, Hong Kong, 2002

Emerg Infect Dis. 2007 Mar;13(3):412-8. doi: 10.3201/eid1303.060365.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Husbandry
  • Animals
  • Case-Control Studies
  • Chickens
  • Disease Outbreaks*
  • Hong Kong / epidemiology
  • Influenza A Virus, H5N1 Subtype / classification
  • Influenza A Virus, H5N1 Subtype / genetics
  • Influenza A Virus, H5N1 Subtype / isolation & purification*
  • Influenza in Birds / epidemiology*
  • Molecular Epidemiology*
  • Multivariate Analysis
  • Odds Ratio
  • Poultry Diseases / epidemiology*
  • RNA, Viral / genetics
  • Regression Analysis
  • Risk Factors
  • Species Specificity
  • Surveys and Questionnaires


  • RNA, Viral