To protect the U.S. livestock industry from the threat posed by highly pathogenic H5N1 avian influenza, USDA this week shared several actions the department is taking with federal partners to try to limit the spread of the disease.
USDA’s Animal and Plant Health Inspection Service (APHIS) announced a Federal Order requiring the following measures, effective Monday, April 29, 2024:
Mandatory Testing for Interstate Movement of Dairy Cattle
- Before interstate movement, dairy cattle are required to receive a negative test for Influenza A virus at an approved National Animal Health Laboratory Network (NAHLN) laboratory.
- Owners of herds in which dairy cattle test positive for interstate movement will be required to provide epidemiological information, including animal movement tracing.
- Dairy cattle moving interstate must adhere to conditions specified by APHIS.
- As will be described in forthcoming guidance, these steps will be immediately required for lactating dairy cattle, while these requirements for other classes of dairy cattle will be based on scientific factors concerning the virus and its evolving risk profile.
Mandatory Reporting
- Laboratories and state veterinarians must report positive Influenza A nucleic acid detection diagnostic results (e.g. PCR or genetic sequencing) in livestock to USDA APHIS.
- Laboratories and state veterinarians must report positive Influenza A serology diagnostic results in livestock to USDA APHIS.
USDA has identified spread between cows within the same herd, spread from cows to poultry, spread between dairies associated with cattle movements, and cows without clinical signs that have tested positive. On April 16, APHIS microbiologists identified a shift in an H5N1 sample from a cow in Kansas that could indicate that the virus has an adaptation to mammals. Centers for Disease Control and Prevention (CDC) conducted further analysis of the specimen sequence, which did not change their overall risk assessment for the general public because the substitution has been seen previously in other mammalian infections and does not impact viral transmission. Additionally, APHIS’ National Veterinary Services Laboratories found H5N1 in a lung tissue sample from an asymptomatic cull dairy cow that originated from an affected herd and did not enter the food supply.
USDA stressed that they have not found changes to the virus that would make it more transmissible to humans and between people. While cases among humans in direct contact with infected animals are possible, the U.S. Centers for Disease Control and Prevention (CDC) believe that the current risk to the public remains low.
The Federal Order may be viewed here and is effective on Monday, April 29, 2024.
