Tuesday, February 01, 2005

Changes in bird culling practices in Vietnam

An interesting story from China Economic Net compares the bird culling practices of last year's bird flu outbreak in Vietnam to what is being tried this year. In 2004, following advice of outside experts, systematic killing within an area of three kilometers radius around an affected flock was the rule. It became apparent that this was not solving the problem because transmission was taking place during transport of chickens by foot and motorcycles.
"If on a Monday a farm is affected and the previous Saturday the farmer had sold his chickens to his cousin 50 kilometres (30 miles) away, then all the chickens in the cousin's farm too should be slaughtered," [said Patrice Gautier, head of Veterinarians Without Borders (VSF]. "That's much more effective than blindly killing all chickens in a three-kilometre radius."
As a result, the number birds killed has fallen sharply, amounting to about a million this year compared to almost 5 million last year.

While the number of human cases is similar to last year (12 this year compared to 8 at this time last year), everyone is wary the virus will adapt to allow facile human-to-human transmission. Several suspicious family and geographic clusters are being investigated but no conclusions have been drawn. Henry Niman at Recombinomics is keeping track and updating the cluster information for those interested (see the News and Commentary section of his site).