The USDA, FDA and Centers for Disease Control and Prevention (CDC) have confirmed that the “mystery illness” that had been affecting cattle on dairies in Texas, Kansas and New Mexico has been diagnosed as highly pathogenic avian influenza (HPAI). State veterinary and public health officials had been working for a few weeks to pinpoint the cause of the illness, which had been causing decreased lactation, loss of appetite, fever and a drop in rumen motility mostly in older dairy cows.
The news comes just days after a juvenile goat in Minnesota was confirmed as the first case of an HPAI-infected ruminant in the U.S.
As of March 25, positive tests of HPAI had come from unpasteurized, clinical milk samples of milk from two dairies in Kansas and one in Texas, as well as from an oropharyngeal swab from another dairy in Texas. Additional testing is still underway after some farms reported finding deceased wild birds on their properties. Based on the findings so far, HPAI infections in cattle appear to have been introduced by wild birds. Infected cattle do not appear to be transmitting the virus to other animals. This concurs with previous research, which to date indicates that ruminants are “dead-end” hosts, meaning they cannot transmit HPAI to other animals. No change in the virus has been found that would make it more transmissible to humans, according to the National Veterinary Services Laboratories; risk to the public is therefore deemed to be low.
So far, HPAI has not been detected in beef cattle. The USDA reports no concern about the safety of the commercial milk or meat supply.
