WASHINGTON, April 2 (Reuters) - Turkeys at a farm in West Virginia have tested positive for what government officials believe is a low-pathogenic strain of the bird flu virus, the U.S. Agriculture Department said late on Sunday.

Preliminary tests indicated the turkeys had a low-pathogenic H5N2 avian influenza virus. USDA officials said they can say "for certain" it"e;s not the highly pathogenic H5N1 virus that has spread through birds in Asia, Europe and Africa.

"Every indication is that the virus is consistent with low pathogenic strains of avian influenza, or LPAI, which are commonly found in birds and typically cause only minor sickness or no noticeable symptoms," USDA Chief Veterinarian John Clifford said in a statement.

He added the detection in West Virginia should not "significantly impact" exports of U.S. poultry.

The samples were collected by an industry group as part of a routine before slaughter, USDA said. The birds showed no sign of illness or mortality. The samples were collected on Friday from a flock of about 25,000 birds that will now be destroyed to prevent the virus from mutating and spreading.

USDA did not identify the farm where the disease was discovered.

A low-pathogenic strain, which produces less disease and mortality in birds than does a high-pathogenic version, poses no threat to humans.

USDA did not identify the

In an effort to monitor for bird flu, USDA and the Department of Interior worked with states to collect more than 100,000 wild bird samples in 2006. The testing program detected a low-pathogenic bird flu strain in six states.

The latest highly pathogenic H5N1 bird flu strain in Asia, Europe and Africa is known to have killed at least 169 people and forced hundreds of millions of birds to be destroyed.