May 28, 2004 (CIDRAP News) – A flock of 24,000 chickens at a farm in northeastern Texas was destroyed yesterday because of evidence of a new outbreak of avian influenza, according to the Texas Animal Health Commission (TAHC).

The chickens were euthanized and buried after routine blood tests indicated the presence of an H7N3 avian flu virus, the TAHC said in a news release. Dr. Bob Hillman, TAHC executive director, said there was little evidence of increased illness or death in the flock, indicating that the virus may have low pathogenicity.

"The National Veterinary Services Laboratory in Ames, Iowa, has reported the evidence of H7N3 AI [avian influenza] virus in the flock, but it may be a week or 10 days before virus isolation results are available," Hillman stated.

The last avian flu outbreak in Texas involved a highly pathogenic H5N2 virus at a farm east of San Antonio in February. About 6,600 birds were sacrificed to contain the disease, and no other cases were found in the vicinity, the TAHC said.

The widespread outbreaks of avian flu in Asia this year have involved a highly pathogenic H5N1 virus. The virus jumped to humans, causing 34 documented cases and at least 23 deaths, and triggered fears of a human flu pandemic. But the virus apparently never spread directly from person to person.

Hillman noted that Canadian officials are continuing an effort to eradicate an outbreak of highly pathogenic H7N3 avian flu in southern British Columbia. He called that outbreak unrelated to the Texas one.

Pilgrim"e;s Pride Corp., owner of the flock that was sacrificed yesterday, said the birds were breeder chickens, which lay eggs for hatching. A company statement said the farm, operated by a contract grower, is 6 miles from the nearest commercial poultry farm.

Pilgrim"e;s Pride President O.B. Goolsby said poultry flocks in Texas are tested for avian flu every 10 weeks. "As a result of this diligence, we believe that the virus can be contained, particularly since this flock is so far from any other poultry farms," he said. He added that the company had stepped up its surveillance for avian flu after the outbreaks earlier this year in Texas and the northeastern United States.

The source of the virus in the new outbreak, near Sulphur Springs in Hopkins County, was unknown, but migratory waterfowl are a natural reservoir of avian flu viruses, Hillman said.

Although the virus may be low-pathogenic, it was necessary to act quickly to stamp out the new outbreak, Hillman said. He noted that avian flu does not make cooked poultry or eggs unsafe.