Top US turkey producer confirms another bird flu case

CHICAGO — A virulent strain of avian flu has spread for the first time to poultry in South Dakota and infected a fourth turkey flock in Minnesota, the nation’s top turkey producer, the U.S. Department of Agriculture said on Thursday.

The latest infections of H5N2 flu show the virus, which can kill almost an entire poultry flock in 48 hours, continues to be a risk to U.S. trade.

Recent flu infections in states stretching from Arkansas to Oregon have prompted overseas buyers to limit imports of U.S. poultry from companies such as Tyson Foods Inc, Pilgrim’s Pride Corp and Sanderson Farms Inc.

In Minnesota, the H5N2 flu was confirmed in a commercial flock of 21,000 turkeys in Nobles County, in the southwest corner of the state, according to the USDA. The birds will be culled and the farm quarantined to prevent the virus from spreading.

The infection represents a new introduction of the flu in Minnesota, said Erica Gunderson, spokeswoman for the state’s Board of Animal Health. The geographic separation outbreaks in the state and staggered timing of infections prove the virus has not spread from one farm to another, she added.

Wild waterfowl appear to be transmitting the disease, Gunderson said.

Molecular testing has shown the H5N2 virus found is nearly identical to viruses isolated in migratory ducks, according to the USDA. But wildlife experts have been skeptical of suggestions that wild birds are responsible for spreading the flu in the Midwest.

On Friday, Minnesota is lifting a 10-kilometer quarantine zone that restricted the movement of poultry around the state’s first case of H5N2 flu in Pope County, which was confirmed on March 4, Gunderson said. Two rounds of tests on nearby poultry have shown other farms were not infected, she said.

In South Dakota, the H5N2 strain was found in a commercial flock of 53,000 turkeys in Beadle County, in the eastern third of the state. Those birds also will be culled and the farm quarantined.

No human infections of the virus have been detected yet, according to the USDA.