USDA: Test for bird flu before interstate transport of cattle

Michigan officials said the H5N1 bird flu virus has infected three additional dairy herds in the state, just as the USDA recommended farmers test their herds for the virus before moving cattle between states.

The tests “should both give us more … information and should mitigate further state-to-state spread between herds,” said the USDA’s animal health agency.

With the new outbreaks in Michigan, highly pathogenic avian infuenza (HPAI) has been confirmed in 29 dairy herds in eight widely dispersed states, from Idaho to North Carolina. Texas has the largest number of infected herds, 11, followed by New Mexico with six and Michigan with five.

“What is happening in Michigan with HPAI mirrors what is happening in states across the country,” said Michigan state agriculture director Tim Boring. “This virus does not stop at county or state lines, which is why we must all be on guard.”

“We are strongly recommending testing before herds are moved between states, which should give us more testing information and should mitigate further state-to-state spread between herds,” said the Animal and Plant Health Inspection Service, the USDA animal health agency. A mandatory testing program for the 26,000 U.S. dairy herds would not be practical or feasible, said APHIS. “Right now, we are seeing that a small portion of the affected herds are becoming ill and that the number of herds exhibiting symptoms is relatively small.”

As its name indicates, HPAI is a lethal disease among birds; the virus can wipe out a flock quickly. As a matter of course, animal health officials quarantine poultry farms when there is an outbreak and kill all the birds in an attempt to stop the spread of the disease.

“HPAI doesn’t affect dairy cows the same way as it does poultry. With proper veterinary care, cows are recovering,” said Dr. Nora Wineland, the Michigan state veterinarian.

Among dairy cows, HPAI causes a reduction in appetite and in milk production, most often among older cows. The infected cattle recover within a couple of weeks.

The Michigan Agriculture Department said the new outbreaks in dairy cattle occurred in Ionia, Isabella, and Ottawa counties. By coincidence, outbreaks of HPAI were reported at two poultry farms with a combined 4 million hens last week in Ionia County, midway between Grand Rapids and Lansing, the state capital, in central Michigan.

Authorities say HPAI is spread by wild birds, with an elevated risk during migratory seasons. The virus can be spread directly by birds through their secretions and droppings or indirectly through equipment, feed, or clothing that has been exposed to the virus. Farmers are encouraged to use good biosecurity practices, which include limiting access by outsiders to their barns.

“The recent detection and confirmation of HPAI in domestic livestock by USDA has raised questions regarding the emerging threat and potential risks for swine herds,” said the Swine Health Information Center and the American Association of Swine Veterinarians. They scheduled a webinar on Friday to “provide the latest information on influenza A virus,” another name for viruses found in animals.