May 9, 2006
Bird markets pose major threat for transfer of deadly avian flu virus across U.S. borders, according to Lab of O expert
Although migratory birds could bring the deadly H5N1 strain of avian influenza to the United States this year, the most dangerous entry point for the virus, many experts believe, is the bird-trade industry.
"The entrance of highly pathogenic H5N1 to the U.S. may not only come from wild birds, but also from sources such as the domestic and international trade of pet, song and cage birds to the U.S.," said Eduardo Iñigo-Elias, who heads the Cornell Lab of Ornithology's Neotropical Bird Conservation Program. He also is among the lab experts who track and interpret the latest developments related to avian flu.
The bird trade consists of live birds that are wild-caught or bred in captivity, as well as poultry from around the world. The production, transportation and sale of poultry, pet, song or caged birds, homing pigeons, farmed ostriches and game birds are often combined in the same regulated and unregulated markets, said Iñigo-Elias.
Poor sanitary conditions and close contact between stressed birds plague some facilities and provide the ideal setting for transmission of such diseases as deadly strains of the avian flu virus. Transporting infected live birds and products results in the further spread of disease, said Iñigo-Elias. And while members of the Lab of Ornithology avian flu task force believe it is unlikely that a migratory bird will infect humans or poultry in this country, an infected live bird that gets smuggled or handled regularly could pose a greater risk to people and birds.
Regulation of the bird trade is another issue, pointed out Iñigo-Elias. Even regulated markets include smuggled birds. The Wild Bird Conservation Act forbids illegal trade of wild birds in the United States, yet wild birds are often smuggled in and claimed to be bred in captivity. International trade of wild birds includes the illegal transfer of some 5 million to 7 million birds with dubious records, said Iñigo-Elias. Some say the true figure is three times that number. On the black market, a black palm cockatoo can go for between $35,000 and $45,000, and a gyrfalcon can run between $25,000 and $35,000.
In 2004, for example, Iñigo-Elias noted, a man was caught in Belgium trying to smuggle two wild-caught mountain hawk eagles in his hand luggage after buying the birds in a Thai market -- both birds carried the deadly strain of H5N1. In 2005, Taiwanese, Chinese and Hong Kong authorities documented virulent H5N1 in pet birds such as mynahs, house crows and common magpies in pet bird markets. And last October, a macaw from Latin America died of deadly H5N1 while in British quarantine and was likely infected in quarantine by birds from Taiwan. Pet owners and bird-related businesses globally fear that if they report cases of dead birds, authorities may confiscate and destroy remaining pets or captive flocks.
Further, there has been a rash of smuggled live and dead poultry from China, as farmers try to unload their flocks before they are infected, Iñigo-Elias said. In April, chickens seized in Vietnam smuggled from China tested positive for the virile bird flu. In March, U.S. authorities confiscated a smuggled shipment of chicken feet, labeled as "jellyfish," from Thailand into Connecticut.
"When U.S. customs gets a shipment, it's very remote that they get a chance to review that shipment," said Iñigo-Elias. "They are understaffed."
The U.S. government now requires that customs officials test for H5N1 in statistically significant samples of birds entering the country. While thousands of samples are regularly taken, the United States has only one laboratory certified to conduct H5N1 tests -- the Plum Island Animal Disease Center, located off the northeastern tip of New York's Long Island.
At the same time, nobody knows which birds are resistant to this strain of H5N1, allowing some birds, such as geese and young ostriches, to carry the virus without showing symptoms.