All flocks test negative for avian flu, but 'victory' not yet declared
Kerry Craig | News-Telegram Assistant Editor

June 17, 2004 -- Since the initial discovery in May of avian influenza in two commercial chicken operations in Hopkins County, investigators from the Texas Animal Health Commission [TAHC] have been busy with follow-up checks of more than 315 non-commercial poultry flocks in the county. All flocks have tested negative for AI.

Dr. Max Coats, deputy director for TAHC, said the state agency is hopeful the situation in Hopkins County has been contained and eradicated, but a "declaration of victory" will not be made until a second round of tests are completed later this month.

"With any luck, and lots of hard work, the field teams will return to their regular duties by early July, and Texas will remain free of AI," Coats concluded.

TAHC initiated intensive flock testing in an area of about 300 square miles in Hopkins County after a commercial flock of breeding chickens tested positive May 26 for the H7N3 strain of AI on routine blood tests. Although the commercial flock exhibited no clinical signs of AI, about 24,000 breeder chickens were euthanized and buried on site to protect against the spread of disease.

A few days later, a second commercial breeder flock on a nearby farm had positive preliminary blood tests, and this flock, also with about 24,000 birds, was euthanized and buried.

A task force of about 30 TAHC and U.S. Department of Agriculture field staff combed an area extending 10 miles out, identifying 315 noncommercial flocks and one additional commercial breeder flock for AI testing.

"Now the two-person testing teams are battling heat and humidity for a second round of testing on all flocks, standard procedure for ensuring that AI has been eradicated and for regaining international trading status," said Dr. Coats.

Investigators consider their work serious and utilize special clothing to protect themselves against coming in contact with the virus. The special clothing, combined with high temperature and humidity levels make the job far from pleasant, according to TAHC spokeswoman Carla Everett.

"It's not glamorous work, but it is serious work," Everett said.

She said the teams, comprised of state and federal animal health personnel, pull on two pairs of disposable "booties" over their shoes, wiggle into ill-proportioned, oversized disposable coveralls, squeeze into purple rubber gloves, and top off their outfits with an all-purpose, opaque hairnet"

The inspection teams disinfect equipment before collecting blood samples or swabs from chickens, ducks, turkeys, emus or other bird species.

After samples are obtained, the testing team must then reverse their biosecurity operation by bagging and disinfecting their disposable garb, re-cleaning equipment, and spraying their truck tires with a germ-killer before proceeding down the road to the next location.

The samples are first sent to Texas Veterinary Medical Diagnostic Laboratories in College Station, Center and Gonzales for testing. Those samples are forwarded to the National Veterinary Services Laboratory in Ames, Iowa, for confirmation.

Dr. Coats said that because the avian influenza virus could not be isolated from the two commercial flocks that tested positive, he was considering the outbreak a "low-pathogenic," or less deadly form, of the virus.

Dr. Coats explained that there are many strains of AI, and those most deadly to birds are classified as "highly pathogenic." Even low-pathogenic forms of AI must be eradicated, as the virus can mutate, evolving into deadlier forms of the disease, he said.

Despite a complete epidemiological review, the task force has not yet determined how the disease was introduced into the area. However, Dr. Coats said migratory waterfowl are a natural reservoir for the disease, and it is possible that infected birds shed the AI virus in droppings or through respiratory discharge.

"Biosecurity is extremely important when dealing with poultry flocks and other birds," he noted. "Disinfect your boots and put on disposable coveralls or clean clothes before walking into poultry pens or houses. Make sure you're not bringing in viruses or bacteria on equipment, disinfect tools with bleach and water or a commercial disinfectant. As an added precaution, disinfect vehicle tires before entering your premise, so you don't haul the disease in. Ask visitors to park away from your facilities, and if they visit your flock, ensure that they also follow biosecurity measures."

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