Continuing their investigation into a disease event affecting primarily older dairy cows in Texas, Kansas and New Mexico, the U.S. Department of Agriculture, Food and Drug Administration, and Centers for Disease Control and Prevention announced the detection of highly pathogenic avian influenza virus in laboratory samples obtained from some affected cows.
This is the first time that HPAI has been identified as affecting dairy cattle and only the second time HPAI has been detected in a ruminant. Earlier this month, H5N1 was found in goats in Minnesota on a farm where poultry first tested positive. While it is too early to conclude that HPAI is responsible for illness in all of the affected dairy cattle, this finding marks important progress toward confirming a cause.
“The first detection of HPAI in dairy cattle in Texas and Kansas underscores the importance of adherence to biosecurity measures, vigilance in monitoring for disease, and immediately involving your veterinarian when something seems ‘off’. A complete evaluation, including the collection and submission of laboratory samples and reporting to state animal health officials when appropriate, and in a timely fashion, are incredibly important. The AVMA is committed to supporting veterinarians with the latest information and guidance to protect the health and safety of animals under their care,” said Rena Carlson, DVM, president of the AVMA.
HPAI virus was identified in samples that included unpasteurized milk from one dairy farm in Texas and two in Kansas, as well as an oropharyngeal swab from anther dairy in Texas. Testing for HPAI was initiated on March 22, because affected farms had also reported finding deceased wild birds on their properties, and the presence of HPAI was confirmed by National Veterinary Service Laboratories today. Additional testing is underway, including genome sequencing, to characterize the HPAI strain(s) associated with the detections.
Safety of dairy and meat product and public health
USDA, FDA, and CDC have confirmed there are no current safety concerns regarding the commercial milk supply, nor does this situation pose a particular health risk more generally to consumers. State and federal guidelines exist to ensure the safety of dairy and meat products. It is standard practice for dairies to process milk for human consumption exclusively from healthy animals, with any milk from animals affected by health issues being diverted from the food supply. Furthermore, the process of pasteurization, a mandatory step for all milk entering interstate commerce, is effective in eliminating pathogens, including viruses such as influenza. In addition, initial testing by the National Veterinary Services Laboratories has not found changes to the HPAI virus in dairy cattle that would make it more transmissible to humans.
“While this finding of HPAI in dairy cattle is concerning for the health of those animals and their production in the herd, it is crucial to remember that according to the USDA, FDA, and CDC, the risk to our food supply and the public more broadly remains low,” added Dr. Carlson.
Advice for cattle owners and their veterinarians
Cattle owners are advised to monitor their animals closely for signs of disease. The first signs noticed in the current outbreak have been reduced feed intake and reduced milk production. Affected dairies have reported that about 10% of their milking cows have become ill and, thus far, there have been no confirmed deaths associated with HPAI in dairy cattle. Most cattle recover in two to three weeks with supportive care. The AVMA urges producers to promptly report any illness or deaths in their herd to their veterinarian, who may coordinate with state animal health officials for further investigation and response.
Moving forward
Both state and federal agencies are moving quickly to conduct additional testing for HPAI, including viral genome sequencing, to better understand the current situation, and the AVMA is working closely with the American Association of Bovine Practitioners, veterinarians, and state and federal officials in support of these efforts.
The AVMA will continue to monitor this situation closely to offer guidance, support, and updates on further developments. For updates, please visit avma.org. For more information about avian influenza in multiple species, visit https://www.avma.org/resources-tools/animal-health-and-welfare/animal-health/avian-influenza.
