Martin W

Thanks for the link, tho now need subscription to view. Now, this interview – even Int Organisation for Animal Health, which with FAO has been big blamer of wild birds, saying trade looking a more important vector than migrating birds. (Article says conservationists agree wild birds playing a role: all agree wild birds – inc swans – have flown some distances in Europe before dying, but whether they actually spread it to others is not certain.)

PARIS, May 22 (Reuters) – The failure of the H5N1 virus to take hold in wild birds in Africa points to trade not migration as the major factor in spreading the disease on the continent, a top veterinary official said on Monday. Ever since the deadly Asian H5N1 strain of bird flu was found in Nigeria, experts believed wintering birds could carry the virus back to Europe when they returned in the spring. Yet that migration period is now all but over and there have been no cases in Europe directly linked to birds from Africa, where the H5N1 virus has been confined to poultry farms.

Bonaventure Mtei, the World Animal Health Organisation (OIE) representative for southern Africa, said there have been few signs of migratory birds carrying the virus in the continent. "So we think trade is the most critical factor in the interaction of the disease in Africa," he told Reuters during the OIE general assembly in Paris. The findings contrast sharply with the situation earlier this year in Europe, where wild birds migrating from near the Black Sea carried H5N1 as far as France. Infected birds, mostly swans, flew westwards. Hundreds of cases turned up in Europe and some farms were infected. The end of the African migration season has prompted many governments in Europe, including France, to relax curbs on keeping poultry outside. The bans are likely to be re-instated in the autumn when birds from eastern Russia cross Europe again on their way to African wintering grounds.


The migration versus trade theories have been the subject of much speculation. Conservationists have always said that some disease "hotspots" do not correspond to known migratory routes. They admit that migration has played a role in spreading the virus in Europe, but doubt that infected birds could physically fly the distances needed to carry it between Africa and Europe. They also point to the fact that favourite wintering areas in Africa such as Kenya’s Rift Valley have seen no H5N1 cases. "A lot of work has been done to try and sample the wild birds (in Africa)," Mtei said. "To our knowledge so far there is no indication that the virus has been recovered from either migratory or wild birds in Africa," he added. [try telling that to the ridiculous Debora MacKenzie of New Scientist! – but what are facts when you have a good story?]

This leaves trade, either illegal or legal, in poultry as the main risk. He said that while most commercial poultry farms had set up good biosecurity measures, the many small-scale backyard farms had practically none at all. Porous borders and a flourishing informal chicken trade have been seen as key reasons for the spread of the virus across Nigeria and to neighbouring countries. Yet Mtei said it was still too early to rule out any transmission by migratory birds, particularly as the numbers of birds flying the vast distances were huge. [silly fools! – why not look at East Asia??] Experts believe that billions of birds fly from the northern hemisphere to winter in Africa every year. "The migratory theory has not yet been proved false," he said. "We are dealing with large bird populations and we may not have captured sufficient samples." [OIE clinging on, unwilling to admit major mistakes based on tiny evidence and massive supposition]

INTERVIEW-Bird flu in Africa more from trade than migration