Avian influenza viruses in humans: lessons from past outbreaks

BACKGROUND:
Human infections with avian influenza viruses (AIV) represent a persistent public health threat. The principal risk factor governing human infection with AIV is from direct contact with infected poultry and is primarily observed in Asia and Egypt where live-bird markets are common.
AREAS OF AGREEMENT:
Changing patterns of virus transmission and a lack of obvious disease manifestations in avian species hampers early detection and efficient control of potentially zoonotic AIV.
AREAS OF CONTROVERSY:
Despite extensive studies on biological and environmental risk factors, the exact conditions required for cross-species transmission from avian species to humans remain largely unknown.
GROWING POINTS:
The development of a universal (´across-subtype´) influenza vaccine and effective antiviral therapeutics are a priority.
AREAS TIMELY FOR DEVELOPING RESEARCH:
Sustained virus surveillance and collection of ecological and physiological parameters from birds in different environments is required to better understand influenza virus ecology and identify risk factors for human infection.