Rome meet says poultry and unregulated trade cause spread of avian flu
in contrast to the doomsday predictions circulated far and wide by health agencies about avian influenza, birds are now back in Europe from Africa -- but without the bird flu pathogen.
With this, the reasons for the spread of the disease have, for the time, shifted away from the culpability of wild migratory birds. Even a recent meeting held jointly by the Food and Agriculture Organization (fao) and the World Organization for Animal Health (oie) in Rome vindicated the wild birds.
The fao-oie meet hosted over 300 scientists from 100 countries, who deliberated virus ecology, surveillance of birds, sampling and analysis, human and domestic poultry risk, and disease management. But in the absence of proper knowledge about the virus and adequate research into the spread of the disease, scientists are not sure where to put the blame next -- even almost three years after the avian influenza re-appeared in Asia as a potential pandemic threat in late 2003, claiming at least 127 lives across the world.
The two-day long conference witnessed a drastic turn-about in fao's stand of last year, when it blamed the flu solely on migratory birds.
The shift in fao's standpoint has come following the emergence of the disease in Africa, where trade in infected chicks caused the outbreak. A study done by the Wetlands International (wi), an ngo, which conducted extensive tests on migratory birds too exonerated migratory birds. "We tested 5,288 wild birds in 14 African countries but no h5n1 was found in 85 per cent test results that we received," says Taej Mundkur of wi. "Only three per cent contained low-pathogenic virus."
The fao-oie conference thus concluded that although migrating wild birds might be involved in transporting the bird flu virus over long distances, the virus is mainly spread through poultry and the wild bird trade, both legal and illegal. "Good records exist for legal trade, yet around 25 per cent of the 350 million animals crossing borders, worth us $20 billion annually, is considered to be illegal, un-inspected and untested," said William Karesh, member of the fao scientific committee on bird flu. Karesh suggested international regulation, testing before import, which is currently employed for livestock trade, be used for the wild bird trade.
Concerted research While it is important that a regulatory regime for trade is put in place, given that wild migratory birds have been absolved, more urgent research interventions are needed to understand the disease and its epidemiology.
The conference thus called for more focussed inquiry to create a holistic understanding of the virus and the way it spreads, the presence of low pathogenic avian influenza virus in wild birds and poultry, and its relation with the more virulent one. The conference also uncovered major gaps in present scientific knowledge, as scientists remained clueless on questions like whether wild birds are acting as a permanent reservoir of the pathogen -- in case they do, it would mean more outbreaks in subsequent migrations along flyways. Or, on a more positive note, h5n1 could mutate to a less virulent form or subside naturally. During the conference, experts requested developing countries to use vaccines to control the disease in domestic poultry for the global poultry industry is the prime spreader of h5n1 . Robert Webster, a renowned bird flu expert, suggested using vaccines at the agricultural level as well as to follow a standardisation of animal vaccines for antigen content, something that is not done by most agricultural authorities of the world.
As the multi-billion dollar poultry industry continues to bear the brunt of the disease, the fao-oie conference has called for a more concerted focus on research, instead of stockpiling the anti-viral Tamiflu.
Scientists have already warned that the future could bring new outbreaks of the disease in Europe and there should not be any complacency in surveillance of wild birds and poultry.
, DTE News
, Migratory Species