VDACS Provides Update on U.S. Dairy Cattle Influenza Detections

April 15, 2024
VDACS Provides Update on U.S. Dairy Cattle Influenza Detections
The agency confirms that no Virginia cattle have tested positive for influenza infection
Contact: Michael Wallace

In February 2024, an unknown disease began affecting dairy cattle in Texas with symptoms of a temporary decrease in milk production, reduced feed intake, and abnormal milk. In late March, milking dairy cows with these symptoms tested positive for Bovine Influenza A Virus (BIAV), the same strain of the virus that causes Highly Pathogenic Avian Influenza (HPAI) in poultry. The USDA's National Veterinary Services Laboratory confirmed that the strain of the virus in cattle is very similar to the strain originally introduced by wild birds. In most cases, affected cattle have returned to normal in about two weeks.

The Virginia Department of Agriculture and Consumer Services (VDACS) has not confirmed any positive influenza detections within Virginia cattle. In addition to Texas, New Mexico, Kansas, Michigan, Ohio, North Carolina, Idaho, and South Dakota have confirmed cases of influenza in dairy cattle. Several cows that tested positive within a few of these states, became infected after comingling with cows that were shipped from Texas. In other cases, dairy cattle may have independently become infected through natural exposure to wild waterfowl.

As biosecurity is a critical component in reducing the spread of disease, VDACS recommends that new additions to Virginia cattle herds be separated for 21 days to allow any disease symptoms to resolve, and any viral shedding to decrease to a level where it is unlikely to infect other animals. Cattle with abnormal milk or who are otherwise showing signs of illness should be milked last to minimize the chances that they will spread an infectious disease to other cows in the milking string.

After the influenza virus is introduced to a cattle herd, the likely mode of transmission among cattle appears to be through the usage of common milking equipment, as recent detections are within lactating dairy cows, and not others. This finding indicates that it is not highly probable that the disease will spread between affected farms if biosecurity recommendations are followed. As VDACS continues to monitor the recent influenza cattle detections and movement of cattle into the state, the agency may enact additional restrictions as needed.

On April 1, the CDC confirmed that a person in Texas tested positive for this influenza virus, as they developed conjunctivitis. The CDC stated in its announcement that this infection does not change the H5N1 avian flu human health risk assessment for the U.S. general public, which it considers to be low. CDC has interim recommendations for prevention, monitoring, and public health investigations of HPAI (H5N1) viruses at www.cdc.gov/flu/avianflu/hpai/hpai-interim-recommendations.html.

Neither BIAV nor HPAI are food safety concerns. Milk and meat from sick cattle are prohibited from entering the food chain. Pasteurization effectively kills viruses and bacteria in milk, and proper food handling and cooking of meat to a safe internal temperature kills foodborne germs, including the influenza viruses.

If any Virginia cattle owner suspects their cattle have contracted influenza, they should contact their veterinarian immediately. For additional information on the recent cattle influenza detections, please visit www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/livestock.

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