CHICAGO (Reuters) – In the two weeks since bird flu reappeared in Indiana, U.S. veterinarians have swabbed the mouths of chickens and turkeys across the country, racing to uncover any more infections and contain the virus before it causes mass death and damage like last year.

Biologists also are running tests on feces collected from wild birds, which are suspected of spreading the disease to farms.

The U.S. Department of Agriculture confirmed on Jan. 15 that a turkey flock in Dubois County, Indiana, was infected with the H7N8 strain of the virus. It was the first new case of bird flu in U.S. poultry flocks since June.

More poultry flocks will likely fall ill in the coming months, veterinarians said, following an unprecedented outbreak last year that caused more than 48 million chickens and turkeys to die from sickness or because they had to be culled to contain the disease.

Anxiety over that risk is fueling vigilance among U.S. poultry producers and government officials looking for signs of infections. Increased testing could help limit the spread if new cases are detected quickly.

“Everybody’s testing everything,” said John Glisson, vice-president of research for the U.S. Poultry and Egg Association, an industry group.

In the days after the latest outbreak, when winter weather was hampering travel, the USDA arranged for a plane to fly poultry samples from farms near the infected site in Indiana to an Iowa lab to speed up testing, said Denise Derrer, spokeswoman for the Indiana Board of Animal Health.

Typically, the samples would be driven across Illinois.

State and federal authorities culled more than 400,000 birds near the infected farm to contain the outbreak. About 350,000 in the area were killed even though they were diagnosed with a less lethal form of bird flu or tested negative for the disease.

Officials said they wanted to be aggressive to avoid a repeat of last year’s losses. USDA believes the less lethal virus type mutated into a more deadly strain in one flock.

Indiana has required testing in flocks as far as 12.4 miles from the infected farm at least every five to seven days, exceeding the USDA’s standard requirement for testing confined to a zone half that size.

Last year showed the passage of a few weeks without a new infection did not mean the end of the virus.

Minnesota, the nation’s top turkey producing state, confirmed its first infection in poultry on March 5. Its next case was not detected until March 27, and the state subsequently lost 5 million turkeys.

“We’re constantly reminded of what happened in Minnesota last year,” Derrer said.

(Editing by Jo Winterbottom and Matthew Lewis)