Infectious Diseases 2004

Infectious Diseases 2004

Avian Influenza (H7N3) Detected in Hopkins County - Texas

28 May, 2004

A 52-week-old commercial broiler breeder flock with about 24 000 birds (the affected farm is made up of two poultry houses with only 12,000 chickens each) was depopulated and buried Thu 27 May 2004, on a commercial poultry farm in Hopkins County in northeast Texas, near Sulphur Springs.
Routine blood tests indicated that the flock, which lays eggs for hatching, had the H7N3 subtype of avian influenza (AI).
The National Veterinary Services Laboratory in Ames, Iowa, has reported the evidence of the H7N3 AI virus in the flock, but it may be a week or 10 days before virus isolation results are available. "There has been very little evidence of clinical signs of disease or increased mortality in the flock, leading us to believe this may be low-pathogenic AI, which causes little death loss in birds," said Dr. Bob Hillman, Texas state veterinarian and executive director for the Texas Animal Health Commission (TAHC), the state's livestock and poultry health regulatory agency.
This farm supplies hatching eggs to the poultry giant Pilgrim's Pride. Pilgrim's Pride is the second-largest poultry producer in the United States and Mexico.
"The affected Hopkins County flock was negative for the AI virus during routine surveillance tests 10 weeks ago, and the birds have never been moved from the farm," said Dr. Hillman.
"In Texas, we need to take all actions necessary to ensure that this AI outbreak is quickly stamped out even if ours is the low-pathogenic form of the H7N3 AI virus," he said. "Our first priority in Hopkins County was to ensure that the birds were promptly and humanely euthanized, then buried on site, to prevent the potential transmission of disease to other flocks."
The poultry houses will be thoroughly cleaned and disinfected before new birds will be allowed on the farm," Dr. Hillman noted. "TAHC veterinarians and animal health officials are following strict biosecurity measures to prevent transporting virus off the infected farm, or to or from any premise they visit. The field staff will be wearing disposable coveralls, head coverings and gloves, and they'll disinfect their rubber boots, vehicle tires, and equipment prior to entering or leaving a premise."
Laboratory tests on samples collected from area birds will be run at the Texas Veterinary Medical Diagnostic Laboratory in Gonzales or in College Station. Any positive test results will be confirmed at the National Veterinary Services Lab in Ames, Iowa.
"AI has been newsworthy this year, after outbreaks of a different, more dangerous strain were detected and eventually brought under control in Asia," said Dr. Hillman. "Low-pathogenic AI strains also were detected in Pennsylvania, Delaware and New Jersey early this year. Additionally, Canadian officials are continuing efforts to eradicate an unrelated outbreak of a highly pathogenic form of the H7N3 AI virus in British Columbia."
"In February and March, we worked with the U.S. Department of Agriculture to eradicate an outbreak of the highly pathogenic H5N2 strain of AI on a farm in Gonzales County, east of San Antonio. About 6600 birds were depopulated to stop the disease from spreading. Flocks as far as 30 miles from the affected farm were tested, but no additional infection was found," he said (Promed).
Texas exports roughly 10 percent of its $1.06 billion annual production of broilers.
Due to this outbreak report, Mexico banned poultry imports from Texas. The ban covers most poultry products.
Mexico is the fourth-largest importer of U.S. poultry, buying $93 million worth of chicken and related products from its northern neighbor in 2003.