Avian flu

Colorado has highly pathogenic avian influenza – also known as HPAI or bird flu – on a dairy farm, the ninth state with confirmed cases. The U.S. Department of Agriculture’s National Veterinary Services Laboratories confirmed the virus on April 25, 2024, in a herd in northeast Colorado. This farm is one of 35 dairy farms across the U.S. with verified cases of bird flu in cattle as of May 7, 2024, according to the USDA. Bird flu is not new to Colorado. The state experienced an outbreak in poultry that began in 2022. Since then, the USDA’s Animal and Plant Health Inspection Service has reported that 6.3 million birds in nine commercial flocks and 25 backyard flocks have been affected by the virus. The most recent detection was in February 2024. But this is the first time the disease has made cattle in Colorado sick. I’m a veterinarian and epidemiologist at Colorado State University who focuses on infectious diseases in dairy cows. I spent many years...

The discovery of fragments of avian flu virus in milk sold in U.S. stores, including in about 20% of samples in initial testing across the country, suggests that the H5N1 virus may be more widespread in dairy cattle than previously realized. The Food and Drug Administration, which announced the early results from its nationally representative sampling on April 25, 2024, was quick to stress that it believes the commercial milk supply is safe. The FDA said initial tests did not detect any live, infectious virus. However, highly pathogenic avian influenza virus can make cows sick, and the flu virus’s presence in herds in several states and new federal restrictions on the movement of dairy cows between states are putting economic pressure on farmers. Five experts in infectious diseases in cattle from the University of California, Davis – Noelia Silva del Rio, Terry Lehenbauer, Richard Pereira, Robert Moeller and Todd Cornish – explain what the test results mean, ho...

An outbreak of H5N1 avian influenza that started in 2021 has become the largest bird flu outbreak in history, both in the U.S. and worldwide. In the U.S. the virus has led to the destruction of millions of commercially raised chickens, turkeys, ducks and geese, and has killed thousands of wild birds. Many virologists are concerned that this virus could spill over to humans and cause a new human pandemic. University of Colorado Boulder virologists Sara Sawyer, Emma Worden-Sapper and Sharon Wu summarize the compelling story of H5N1 and why scientists are closely watching the outbreak. 1. Is this virus a serious threat to humans? H5N1 is a specific type of influenza virus, predominantly harbored by birds, that was first detected on a goose farm in China in 1996. Recently it has begun infecting an exploding diversity of bird and mammalian species around the globe. The virus is highly pathogenic to birds, meaning that infections often cause extreme symptoms, including death. But...

An outbreak of highly pathogenic avian influenza has spread through chicken and turkey flocks in 46 states since it was first detected in Indiana on Feb. 8, 2022. The outbreak is also taking a heavy toll in Canada and Europe. Better known as bird flu, avian influenza is a family of highly contagious viruses that are not typically harmful to most wild birds that transmit it, but are deadly to domesticated birds. The virus spreads quickly through poultry flocks and almost always causes severe disease or death, so when it is detected, officials quarantine the site and cull all the birds in the infected flock. As of early November, this outbreak had led to the culling of over 50 million birds from Maine to Oregon, driving up prices for eggs and poultry – including holiday turkeys. This matches the toll from a 2014-2015 bird flu outbreak that previously was considered the most significant animal disease event in U.S. history. Yuko Sato, an associate professor of veterinary me...