To further protect the U.S. livestock industry from the threat posed by highly pathogenic H5N1 avian influenza, USDA has announced that it is taking specific actions with its federal partners to limit the disease’s spread.
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
- Prior to interstate movement, dairy cattle are required to receive a negative test for Influenza A virus at an approved National Animal Health Laboratory Network 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 identified a shift in an H5N1 sample from a cow in Kansas that could indicate that the virus has an adaptation to mammals.
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, the 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.
The novel movement of H5N1 between wild birds and dairy cows requires further testing and time to develop a critical understanding to support any future courses of action, USDA said in a statement, adding that requiring positive test reporting will help the agency better under the disease and testing before interstate movement will limit its spread.
The agency has not found changes to the virus that would make it more transmissible to humans and between people and CDC believe that the current risk to the public remains low.
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