Ohio dairy herd tests positive for highly pathogenic avian influenza

dairy cattle look imploringly at the camera person

SALEM, Ohio — A dairy herd in Ohio tested positive for highly pathogenic avian influenza, the Ohio Department of Agriculture announced April 2.

The dairy operation in Wood County received cows on March 8 from a Texas dairy that later confirmed cows were infected with highly pathogenic avian influenza, also known as the bird flu. 

Ohio’s animal health officials were notified when the cows began showing clinical signs similar to sick, lactating dairy cows in other states. 

The Ohio Department of Agriculture said it received a presumptive positive test for HPAI and is awaiting confirmation from the U.S. Department of Agriculture’s National Veterinary Services Laboratory. 

The USDA announced on March 25 that a mystery illness in dairy herds in Texas and Kansas was determined to be highly pathogenic avian influenza.

Since then, the USDA confirmed the detection of HPAI in seven dairy herds in Texas, two in Kansas, one in Michigan, one in New Mexico and one in Idaho. The herds in Michigan and Idaho had also recently received cows from affected herds in Texas, where animals later tested positive. 

One person in Texas who had been in contact with affected cattle tested positive for the bird flu, the Centers for Disease Prevention and Control announced on April 1. This is the second case of highly pathogenic avian influenza in a human since this outbreak began in February 2022. The other person had been in contact with an affected poultry flock. 

State and federal agencies maintain there is low risk to human health and no risk to the commercial milk supply.


Dairy producers in Texas first noticed some cows were sick with an unknown ailment in mid-February. According to the Texas Department of Agriculture, impacted cattle show flu-like symptoms including fever, low appetite, thick and discolored milk along with a sharp reduction in milk production averaging between 10-30 pounds per cow throughout the herd.

The disease seemed to affect mostly older dairy cows in mid-lactation. The virus has been detected in unpasteurized milk samples from sick animals and through throat swabs, the USDA said. Most impacted cows recover with supportive care. 

While there is low risk to human health, people with close or prolonged exposure to infected animals or environments are at greater risk of becoming infected themselves. 

There is still no risk to the commercial milk supply as federal regulation requires milk from sick animals to be diverted or destroyed. Additionally, pasteurization has proven to inactivate bacteria and viruses, like influenza, in milk. 

There is concern, though for economic impacts to individual herds hit by the virus. The Texas Department of Agriculture said affected herds “may lose up to 40% of their milk production for 7 to 10 days until symptoms subside.”

There could also be issues for producers who sell raw milk or use raw milk to make cheese, as the virus is found in unpasteurized milk.

More than 82 million domestic birds have been culled as a result of the current bird flu outbreak, which started in February 2022. The bird flu has been detected in more than 200 mammals, mostly wild animals.

Bird flu detections tend to be higher in the fall and spring as wild birds, primarily waterfowl, that naturally carry the virus migrate and spread it in their droppings. It can spread on farms through contaminated water or people carrying matter from infected birds on their clothing, gloves, shoes, vehicle tires or other equipment.

The first domesticated ruminant to be diagnosed with HPAI was a goat kid in Minnesota in February. The goats lived on a property where a backyard poultry flock had recently been hit by HPAI. The birds and goats had access to the same space and a shared water source. Several goat kids died, but adult goats tested negative for the virus and appeared healthy.

It’s still unclear if the virus can be transmitted from cow to cow, but USDA officials aren’t ruling it out just yet. According to the National Milk Producers Federation, USDA officials are also considering the possibility of “mechanical transmission” in which animals may spread the virus by milking equipment that hasn’t been fully sanitized. 

Farmers across the country are urged to practice good biosecurity, test animals before necessary movements, minimize animal movements, isolate sick animals from the herd, and limit contact between cattle and wild birds.

If movement must occur, the USDA recommends PCR testing animals before movement and isolating animals after movement for a minimum of 21 days before integrating them with the rest of the herd.

Related content:

Bird flu detected in dairy cows in Texas, Kansas

Dairy cows in Michigan diagnosed with bird flu


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