Detection of Highly Pathogenic Avian Influenza (H5N1) inDairy Herds: Frequently Asked Questions

USDA APHIS

Since late March 2024, the U.S. Department of Agriculture, Food and Drug Administration, Centers for Disease Control and Prevention, and state veterinary and public health officials have been investigating the emergence of highly pathogenic avian influenza in dairy cows, with one human infection. USDA’s Animal and Plant Health Inspection Service is maintaining resources, including a list of detections in cattle to date as well as biosecurity information for farmers, veterinarians and farmworkers at Highly Pathogenic Avian Influenza (H5N1) Detections in Livestock | Animal and Plant Health Inspection Service. This is a rapidly evolving situation and USDA, as well as state and federal partners, are committed to sharing updates as information becomes available. Here, we are answering some of the most frequently asked questions about these detections. What is the appropriate nomenclature for this virus, now that it has appeared in dairy cows? From USDA’s perspective, highly pathogenic avian influenza or H5N1 are the most scientifically accurate terms to describe this virus. This is also consistent with what the scientific community has continued to call the virus after it has affected other mammals. As a reminder, genomic sequencing of viruses isolated from cattle indicates there is no change to this virus that would make it more transmissible to or between humans, and the CDC considers risk to the public to be low at this time. However, people with more exposure to infected animals do have a greater risk of infection. Since the virus is not highly pathogenic in mammals, H5N1 is the most fitting of the two scientifically correct options. It is important to note that “highly pathogenic” refers to severe impact in birds, not necessarily in humans or cattle.

Continue reading