Recently a shipment of chicken feet was smuggled into the United States from Thailand, arriving in Connecticut marked "jellyfish." Luckily, our trade surveillance system worked and the chicken parts were confiscated. Over the last 30 years we have learned a tremendous amount about how avian influenza spreads. In nature, avian influenza viruses live innocuously in many types of wild birds and cause only mild effects, sometimes none at all, similar to many bacteria and viruses that live in humans.
This is not to say that the virus can't be carried by, and kill, wild birds, because it can. Yet the spread of H5N1 did not result from the activities of wild birds, but from a very human activity – trade. We know that international trade in wild or exotic birds, both legal and illegal, has helped moved H5N1 around the world. However, the virus has likely gotten its biggest boost through the trade, both legal and illegal, in poultry. As part of a multi-billion dollar industry, poultry markets and farms span the globe. The conditions of these facilities vary greatly; some are plagued by highly unsanitary conditions and close bird-to-bird contact. This environment provides the ideal setting for deadly strains of the avian flu virus to develop.
Moving these infected poultry and poultry products as well as contaminated fecal matter on trucks, boots or in cages results in the further spread of avian flu. The current focus on the role of migratory birds in the spread of H5N1 has shifted discussion away from this trade. … (Robert Cook is chief veterinarian and vice president and William B. Karesh is director of the Field Veterinary Program at the Wildlife Conservation Society, Bronx Zoo, New York.)
Don't blame the wild birds