March 10, 2006

Deadly Bird Flu Not in US Yet: Report

WASHINGTON -- The H5N1 avian flu virus has not yet made its way to North America, although many experts believe it will, U.S. government researchers said on Thursday.

Eight months worth of sampling migratory birds has turned up no evidence of the dangerous H5N1 strain, the team at the U.S. Geological Survey's National Wildlife Health Center said.

The team has been sampling migratory waterfowl, considered to be the most likely carriers of influenza viruses from east Asia across to western North America, notably Alaska and Canada. They found several viruses but not H5N1.

"Avian influenza viruses are common in North American waterfowl and shorebirds, and the finding of a variety of avian influenza viruses is not unexpected," said Dr. Leslie Dierauf, director of the USGS National Wildlife Health Center in Madison, Wisconsin.

The USGS said in a statement that with its partners it would "aggressively" monitor and test for avian influenza in wild birds this year due to the increasing number of countries that have discovered highly pathogenic H5N1 in their migratory birds.

The agency said biologists from several federal and state agencies, universities and nongovernmental organizations planned to collect between 75,000 and 100,000 samples from migratory birds this year.

U.S. Department of Agriculture laboratories that specialize in testing for avian viruses will screen most samples, although USGS labs are equipped to test about 11,000 of those samples in 2006.

So far, the only H5 subtype USGS scientists found was a low pathogenic strain of H5N2 from one duck in North Dakota. There have been several outbreaks of H5N2 in poultry in the United States and Mexico.

Canada recently found low-pathogenic H5 avian influenza subtypes in 250 wild bird samples, including a low pathogenic, H5N1 virus, different to the H5N1 strain.

H5N1 avian influenza has killed or forced the culling of more than 200 million birds since it re-emerged in 2003. While harmless to some duck species, the virus kills chickens within a day or so and is lethal to other species such as swans.

It has spread from east Asia across to western Europe and West Africa.

Experts believe that migratory birds and the poultry trade will eventually spread it to birds around the world. It does not easily infect humans but has sickened 175 people and killed 96 of them.

Health officials fear that the virus could mutate into a form that easily infects humans and say if it did, it would spark a devastating pandemic.