Avian Flu For Me And You?

Perhaps the most frustrating aspect of the news coverage of Avian Flu is the media's general failure to explain how the flu is transmitted from chickens to people. (This AP story, here, from today is a notable exception.) Can the flu be transmitted by handling, cooking, or eating chickens from the Supermarket? Or is the flu transmitted by handling, being exposed to, and slaughtering live chickens?

Avian Flu is breaking out among birds in Asia and Europe. But the reported human cases of Avian Flu have all occurred in Southeast Asian countries. This chart (here) shows that the known cases and deaths have all occurred in Indonesia, Thailand, Cambodia, and Vietnam.

Is there something about those countries that increases the risk of transmission from chickens to humans? This story (here) suggests there is.

"[U.S. Health and Human Services Secretary Mike] Leavitt, who is expected in Indonesia today, told reporters the trip has given him a realistic view of the challenges in Asia, where people and animals living closely together is rooted in the culture.
'I was at a market in Cambodia and talked with a pig vendor who traveled 600 kilometers (373 miles) the night before to sell her pigs," he said. "She had carried them on the top of a bus in a box next to a load of chickens, and I was sitting next to her . . . with several other baskets of geese and several baskets of turkeys and ducks . . . right next to pigs.'" [Ellipsis in original.]

The article fails to explain how transmission may occur, however. That information is easily found on this website (here) from the World Health Organization.

"Direct contact with infected poultry, or surfaces and objects contaminated by their faeces, is presently considered the main route of human infection. To date, most human cases have occurred in rural or periurban areas where many households keep small poultry flocks, which often roam freely, sometimes entering homes or sharing outdoor areas where children play. As infected birds shed large quantities of virus in their faeces, opportunities for exposure to infected droppings or to environments contaminated by the virus are abundant under such conditions. Moreover, because many households in Asia depend on poultry for income and food, many families sell or slaughter and consume birds when signs of illness appear in a flock, and this practice has proved difficult to change. Exposure is considered most likely during slaughter, defeathering, butchering, and preparation of poultry for cooking. There is no evidence that properly cooked poultry or eggs can be a source of infection.

Does the virus spread easily from birds to humans?

No. Though more than 100 human cases have occurred in the current outbreak, this is a small number compared with the huge number of birds affected and the numerous associated opportunities for human exposure, especially in areas where backyard flocks are common. It is not presently understood why some people, and not others, become infected following similar exposures."

Thus, rhe risk of getting Avian Flu from chickens seems slight for consumers who typically have no contact with live chickens.

If the Avian Flu virus ever mutates and becomes transmissible from human to human that's when we'll be in trouble. Big Trouble. (Read more about that here.) Although the risks of infection for most people are not high at this time, the consequences of the Avian Flu spreading and mutating are very high. The best defenses at this time are culling and quarantining. Hong Kong's decision to slaughter its entire chicken supply in 1997 is credited with having prevented a pandemic. (Here.) Hence Romania's decision the other day to quarantine villages and slaughter thousands of chickens where Avian Flu was found. (Here.)

In the meantime, chicken anyone?.

-tdr