Highly pathogenic avian influenza in dairy animals in North Carolina and South Dakota have been confirmed by USDA’s National Veterinary Services Laboratory, bringing the number of states with affected dairy farms to eight.

A total of 28 confirmed cases of HPAI have been confirmed in dairy herds. The last two cases were confirmed in Michigan on April 12, USDA’s Animal and Plant Health Inspection Service reports.

As of April 16, USDA has confirmed HPAI in dairy cattle in 11 herds in Texas, six in New Mexico, four in Michigan, three in Kansas and one each in Idaho, North Carolina, Ohio and South Dakota.

The affected herds in Ohio, Idaho and Michigan had recently imported cattle from Texas herds that later tested positive.

Movement restrictions

The American Veterinary Medical Association earlier reported at least 18 states have restricted imported cattle from states where the virus is known to have infected dairy cattle. Those states restricting cattle are Alabama, Arizona, Arkansas, California, Delaware, Florida, Hawaii, Idaho, Kentucky, Louisiana, Maryland, Mississippi, Nebraska, North Carolina, Pennsylvania, Tennessee, Utah and West Virginia.

Oregon joined that list on Tuesday.

USDA APHIS announced on April 2 it will not be issuing federal quarantine orders at this time, nor is it recommending any state quarantines or official hold orders on cattle.

“However, we strongly recommend minimizing movement of cattle as much as possible, with special attention to evaluating risk and factoring that risk into movement decisions,” the agency said.

Extreme diligence

If cattle must be moved, APHIS strongly encourages “extreme diligence” by producers, veterinarians and animal health officials to ensure only healthy cattle are moving and to ensure the validity of interstate health certificates.

The American Association of Bovine Practitioners announced April 7 it will call this disease bovine influenza A virus to better distinguish the disease syndrome in cattle from the pathogenesis observed in birds.

The H5N1 virus in cattle does not cause high morbidity and mortality as it does in birds and the association does not believe the disease should be referenced as “HPAI in cattle” or “bird flu in cattle” due to those differences, the association stated.