Tests on a suspected case of foot-and-mouth in North Carolina are negative.
Samples of dead pig tissue from a packing plant in Martin County had been sent to agriculture officials to be tested for the disease.
Another sample taken from a separate market is being tested.
"This is something that is not uncommon," said US Agriculture department spokesman Mr Kevin Herglotz. About 700 such tests are done annually, according to the department.
"Whenever we get a suspect case we take it very seriously," Mr Herglotz said.
Department spokesman Mr Jim Knight said a state agriculture inspector at the packing plant in Robersonville, 78 miles east of Raleigh, had seen dead animals and become concerned because of heightened awareness in the state about the disease.
She contacted a USDA inspector who agreed samples should be taken. They were flown to the isolated federal lab on Plum Island, in the Long Island Sound, the only facility where foot-and-mouth testing is done.
Another sample was taken from a Sampson County market, southeast of Raleigh, and sent to the federal lab, Mr Knight said.
The United States has not had a confirmed case of foot-and-mouth since 1929, but federal and state officials frequently test animals that exhibit symptoms similar to those caused by the disease.
PA
