Texas ‘mystery’ illness: USDA confirms first cases of bird flu in US dairy cows

The US Department of Agriculture (USDA) has confirmed that the mystery illness that first struck older dairy cattle in the Texas panhandle is highly pathogenic avian influenza, commonly known as bird flu. The confirmation came after milk from sick animals tested positive for the virus.

USDA, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) alongside veterinary and public health officials are now conducting an investigation and have encouraged farmers to monitor and report cattle illnesses quickly.

Symptoms include sudden decrease in lactation, thicker milk, a drop in feed consumption and in some cases, pneumonia and mastitis. The symptoms of the illness last between 10 and 14 days, with animals recovering on their own, thus not requiring culling of herds similar to what takes place in the poultry sector when birds are affected by the virus.

Farmers who observe clinical signs in their herd consistent with this outbreak should immediately contact their veterinarian. Veterinarians who observe these clinical signs and have ruled out other diagnoses on a client’s farm should contact the state veterinarian and plan to submit a complete set of samples to be tested at a diagnostic laboratory.

For dairies whose herds are exhibiting symptoms, on average about 10% of each affected herd appears to be impacted, with little to no associated mortality reported among the animals, USDA said. Milk loss resulting from symptomatic cattle to date is ‘too limited’ to have a major impact on supply and there should be no impact on the price of milk or other dairy products, the agency said.

The disease doesn’t appear to affect dry cows.

USDA has highlighted that there is also no threat to human health and milk and dairy products remain safe to consume. “At this stage, there is no concern about the safety of the commercial milk supply or that this circumstance poses a risk to consumer health. Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted or destroyed so that it does not enter the food supply. In addition, pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk.”

Federal and state agencies are ‘moving quickly to conduct additional testing for the virus’ as well as viral genome sequencing to better understand the situation and to characterize the HPAI strain or strains affecting US dairy cows.

Industry bodies warn against ‘unnecessary or unfair’ impacts to trade

In a joint statement, the National Milk Producers Federation (NMPF), the International Dairy Foods Association (IDFA), the U.S. Dairy Export Council (USDEC) and Dairy Management Inc. (DMI) said that enhanced biosecurity protocols were underway on dairy farms. “As information related to an illness affecting dairy cows in several states began to circulate over the past two weeks, USDA’s Animal and Plant Health Inspection Service worked with state veterinary authorities as well as federal partners including the FDA to swiftly identify and respond to detections and mitigate the virus’ impact on US dairy production.

“Dairy farmers also have begun implementing enhanced biosecurity protocols on their farms, limiting the amount of traffic into and out of their properties and restricting visits to employees and essential personnel.”

They added that the matter is ‘an animal health issue, not a human health concern’, adding that ‘mammals including cows do not spread avian influenza’ and is ‘extremely rare’ for the virus to affect humans as that requires prolonged contact with an infected bird. Biosecurity practices guidance is available here​.

The trade organizations are also working with the federal government, the World Organization for Animal Health and trading partners to ‘minimize all unnecessary or unfair trade impacts’. “It is essential that trading partners do not impose bans or restrictions on the international trade of dairy commodities in response to these and future notifications and rely on the science-based food safety steps taken in US dairy processing, namely pasteurization, in preserving market access,” the organizations said.