The hypothesis that migratory birds are responsible for spreading avian flu over long distances has taken another knock. Last year, an outbreak of the deadly H5N1 strain in thousands of migratory birds at Qinghai Lake in western China provided what seemed the first firm evidence for the idea. Because the lake is so remote, experts assumed infected birds had flown up from southern China.
But it has now emerged that, since 2003, one of the key migratory species affected, the bar-headed goose, has been artificially reared near the lake. The breeding farms — part of an experimental programme to both domesticate the birds and release them to repopulate wild stocks — raise the possibility that farmed birds were the source of the outbreak.
Here’s the blogger portion:
Ironically, the breeding programme was revealed by Chinese press agencies reporting on the government’s efforts to boost agriculture and the environment in the region ahead of the opening of the Qinghai-Tibet railway in July; the railway is expected to promote tourism and economic growth.
Richard Thomas of BirdLife International in Cambridge, UK, spotted the press cuttings, and posted English translations to a blog (http://www.drmartinwilliams.com).
(Kudos to story author Declan Butler, a blogger himself, for including that part of it).
There’s still a lot of conflicting evidence regarding the role of migratory birds in influenza transmission. Based on this evidence alone no one can say that it was domestic–rather than wild–birds that caused the outbreak at Qinghai Lake, but it certainly puts the evidence (previously holding up this location as a relatively firm case of movement of the virus due to wild birds) back into play.