April 25, 2024— Since late March 2024, the United States Department of Agriculture (USDA), Food and Drug Administration(FDA), Centers for Disease Control and Prevention (CDC), state veterinary and public health officials, laboratories, and accredited veterinarians have been investigating the emergence of the HPAI, H5N1 virus in dairy cows.
To date, USDA has confirmed HPAI H5N1 clade 2.3.4.4b virus detections on 33 dairy cattle premises in 8 states (Kansas, Idaho, Michigan, New Mexico, North Carolina, Ohio, South Dakota, and Texas). While Colorado does not currently have a confirmed case, we are actively performing investigations on dairies in our state.
USDA Federal Order:
In order to continue to monitor and understand the extent of this virus and reduce the risk of further disseminating HPAI H5N1 virus, resulting in greater threats to poultry and livestock, the USDA issued 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 (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.
As part of the Federal Order, the USDA will be releasing guidance documents to clarify the process for mandatory testing. The State Veterinarian’s Office will work to disseminate that information through our mailing list as soon as that information becomes available. If you are not signed up for emails from the State Veterinarian’s office, you can sign up here to receive those updates.
Information for Colorado Veterinarians:
Clinical signs reported in affected dairies include:
- for cattle with monitors, decreased rumination appears to be an early indicator of disease
- decrease in feed consumption;
- tacky or loose feces;
- acute drop in milk production;
- some severely impacted cows experiencing thicker, concentrated, colostrum-like milk;
- low-grade fever.
Impacted animals were primarily older cows in mid-lactation, while dry cows, heifers, and young stock do not appear to be clinically affected. For the dairies whose herds are exhibiting symptoms, on average about ten percent of each affected herd appears to be impacted, with little to no associated mortality reported among the animals.
Clinically affected cattle seem to recover after supportive care.
Case Reporting:
We encourage veterinary practitioners to report any condition that may indicate affected animals in Colorado to our office at (303)-869-9130, via the Reportable Disease Case Report Form, or to their local Veterinary Medical Officer.
Colorado veterinary practitioners who have herds with clinical signs consistent with this syndrome and who wish to submit samples for HPAI testing must contact our office before sample submission. We will provide guidance for sample collection and submission and a Foreign Animal Disease (FAD) number. Samples will not be processed at the CSU VDL without this number.
Practice Enhanced Biosecurity:
- Enhanced biosecurity guidance is available through:
- Secure Milk Supply Program: https://securemilksupply.org/ and,
- National Dairy FARM Program
https://nationaldairyfarm.com/dairy-farm-standards/farm-biosecurity/.
- Producers should consider pasteurization of all milk products being fed to calves.
- Limiting interactions with wild birds, including direct contact with birds and wild bird feces, may reduce the risk of exposure to the H5N1 virus. You can learn more about wild bird biosecurity on CDA’s HPAI website.
Updates and Contact Information:
This is a rapidly evolving situation, and CDA, USDA, and other federal and state partners will continue to share additional updates as soon as information becomes available. CDA will provide updates on CDA’s HPAI website.
Please contact our office directly at 303-869-9130 or [email protected] if you have any questions or concerns.
