Close contact with live poultry has been implicated in recent outbreaks of avian influenza in humans in Southeast Asia and elsewhere (2, (5) (6) (7) (8) . In the 1997 Hong Kong outbreak, live bird markets were implicated as the source of exposure to the virus (8) . In the United States, live bird markets are a known reservoir for avian influenza (9-11), but thus far they have not been associated with human avian influenza infection. Live bird markets involve a mixing of birds from diverse areas, crowded conditions for humans and livestock, mixing of different species of animal, and often a lack of proper sanitation, thus providing opportunity for outbreaks of disease. Transport of animals to market is a source of stress than can induce increased shedding of infectious agents. Stressed birds are also more susceptible to infections (12) .