As new cases are reported to the Animal and Plant Health Inspection Service, this story will keep evolving. To date, an alarming 650 dairy herds in 15 states have been found carrying Highly-Pathological Avian Influenza (HPAI), a virus initially discovered in wild birds and commonly associated with turkey and poultry flocks. The first known transmission in a dairy cow herd was announced on March 25 by the U.S. Department of Agriculture (USDA), with herds in Kansas and Texas falling ill and testing positive.

Symptoms and Recovery in Dairy Cows

Some dairy cows have tested positive for HPAI even without showing symptoms. According to the USDA, in most cases, dairy cattle exhibit symptoms such as a drop in milk production, loss of appetite, and changes in manure consistency. The Kansas Department of Agriculture has listed these symptoms. It's important to note that while HPAI is usually fatal for poultry and turkey, dairy cows generally recover within about two weeks with proper treatment. A Reuters report confirmed that cows infected with bird flu have been culled or died in five of the 15 U.S. states with confirmed cases.

What the USDA is Doing

The USDA's Animal and Plant Health Inspection Service (APHIS) has taken significant steps. They released 239 genetic sequences found in the recent H5N1 and HPAI influenza viruses in dairy cattle and poultry for interested researchers. APHIS is also urging dairy cattle producers and those in the industry to share epidemiological information from affected farms, even if they aren't planning to move cattle interstate. The USDA emphasized the CDC's assessment that humans are at low risk of contracting the disease. As of September 9, thirteen people in Texas, Colorado, and Michigan have tested positive for contracting H5N1. Most recently, a patient in Missouri was reported to be sick with the bird flu despite no known contact with cattle or poultry. On August 28, at a farm show in Iowa, Vilsack announced that the USDA has approved field testing on an H5N1 vaccine for cattle.

AABP's Decision on Disease Naming

In an open letter dated April 8, 2024, the American Association of Bovine Practitioners (AABP) presented a compelling argument. Since the disease in cattle doesn't cause high morbidity and mortality like in birds, they believe it shouldn't be referred to as "HPAI in cattle" or "bird flu in cattle." Instead, they will call it Bovine Influenza A Virus (BIAV) in their messaging and resources. The AABP encourages other organizations, state animal health officials, diagnostic labs, and state and federal agencies to use this name to better distinguish between the diseases in cattle and birds. They emphasize that it's crucial for the public to understand the difference to maintain confidence in the safety and accessibility of beef and dairy products.

What the FDA is Doing

The FDA found particles of HPAI in samples of pasteurized milk. In a release, they stated that they have full confidence in the safety of milk sold in grocery stores. Based on available information, pasteurization is likely to inactivate the virus, but the process may not remove all viral particles.

California at the Center of the Outbreak

In the last two months, California has become the state with the most cases of HPAI in cattle. Since the outbreak began in March 2024, APHIS has reported 233 confirmed cases of HPAI in dairy cattle in California. In just the last 30 days, California has confirmed 233 livestock herds with positive tests for H5N1. Human infections have also been on the rise in the state, with 16 of the 52 total confirmed bird flu cases in humans this year coming from California. California produces the most dairy products among all U.S. states.

Outbreak Timeline

Successful Farming will continue to report on the HPAI/dairy cow situation. Here is an updated list of our coverage from 2024:NovemberOctoberSeptemberAugustJulyJuneJune 28: Two more Iowa dairy herds reported with avian fluJune 25: USDA: Expect more cases of bird flu in dairy cattleJune 25: Four states to begin voluntary testing for bird flu in dairy farm milk tanksJune 25: What can farmers learn from the current bird flu outbreak in dairy cows?June 17: Bird flu found in two more Iowa dairy herdsJune 14: Two dozen companies working to find bird flu vaccine for cows, U.S. agriculture secretary saysJune 14: H5N1 virus was spread by cattle, people, and shared equipmentJune 11: Iowa asks USDA to compensate farmers for cows culled due to H5N1 virusJune 10: Iowa identifies second dairy with bird flu and expands testingJune 7: Block sales of raw milk that may contain H5N1 virus, FDA asks statesJune 6: Bird flu infects dairy herd in Iowa, 10th state to be hitJune 6: Cows infected with bird flu have died in five U.S. statesJune 6: Bird flu outbreak reported in Minnesota dairy herd, the state's firstJune 4: USDA aims to isolate and exhaust H5N1 virus in dairy herdsJune 4: Bird flu's spread from poultry to cattle to humans provokes worry among feds and statesJune 3: Farmworkers face high-risk exposures to bird flu, but testing isn't reaching themMayApril