Current H5N1 Bird Flu Situation in Dairy Cows – CDC

Domestic Summary

On April 1, CDC confirmed one human HPAI A(H5N1) infection in a person with exposure to dairy cows in Texas that were presumed to be infected with the virus. This is thought to be the first instance of likely mammal to human spread of HPAI A(H5N1) virus. In May 2024, CDC began reporting additional, sporadic human cases in people who had exposure to infected dairy cows. That latest human case counts are available at H5N1 Bird Flu: Current Situation Summary.

CDC systems that monitor national, state, and local level influenza data are being used during the current avian influenza A(H5N1) situation. These systems show no indicators of unusual influenza activity in people, including avian influenza A(H5N1).

While rare, mammals can be infected with highly pathogenic avian influenza (HPAI) A(H5N1) ("H5N1 bird flu") viruses. Reports of these sporadic infections in mammals have occurred globally amid widespread outbreaks of bird flu infections in wild birds and poultry.

Mammals can be infected with H5N1 bird flu viruses when they eat infected birds, poultry, or other animals and/or if they are exposed to environments contaminated with virus. Spread of H5N1 bird flu viruses from mammal to mammal is thought to be rare, but possible.

Globally, sporadic HPAI A(H5N1) virus infections in mammals have been reported across the continents of Asia, North America, South America, and Europe. More information about the global impact of avian influenza can be found here: Avian Influenza - WOAH - World Organisation for Animal Health.

Specifically, recent HPAI A(H5N1) infections in mammals have been detected in sea lions in Peru and Chile, sea elephants in Argentina, and foxes in Canada, France, and other countries. A list of significant HPAI outbreaks, including in mammals, can be found here: Highlights in the History of Avian Influenza

The wide geographic spread of HPAI A(H5N1) viruses in wild birds, poultry, and some other mammals, including in cows, could create additional opportunities for people to be exposed to these viruses. Therefore, there could be an increase in sporadic human infections resulting from bird and animal exposures, even if the risk of these viruses spreading from birds to people has not increased. CDC believes the current risk to the general public from bird flu viruses is low. People who have job-related or recreational exposure to infected birds or animals, including cows, are at greater risk of contracting HPAI A(H5N1) virus. CDC has recommendations related to testing, treatment of HPAI A(H5N1) infection and prevention of exposure to these viruses: Highly Pathogenic Avian Influenza A(H5N1) Virus in Animals: Interim Recommendations for Prevention, Monitoring, and Public Health Investigations.

This page outlines CDCs recommendations for preventing exposure to avian influenza viruses.

This guidance identifies select occupational groups that may be at risk to novel influenza A viruses

This page outlines CDCs recommendations for preventing exposure to avian influenza viruses.

CDC continues to respond to the public health challenge posed by the outbreak of avian influenza A(H...

This is the first time this virus has been found in cows and the first case of cow-to-human bird flu

CDC public health news, press releases, government public health news, medical and disease news, sto...

CDC Reports First U.S. Human Infection in 2024 with Variant Influenza Virus

CDC public health news, press releases, government public health news, medical and disease news, sto...

CDC is working closely with USDA to monitor the current H5N1 bird flu situation in wild birds and po...

Avian influenza A viruses usually do not infect people, but there have been some rare human cases

Avian influenza refers to disease in birds caused by infection with avian influenza Type A viruses.

Bird flu viruses mainly spread among wild birds & domestic poultry but can spread to other animals.

In recent years, HPAI H5N1 infections have been detected in mammals including but not limited to wild or feral animals such as foxes, bears, and seals; stray or domestic animals such as cats and dogs; farm animals, such as goats, cows, and mink, and zoo animals such as tigers and leopards. A timeline, which includes mammalian detections of bird flu, can be found here: Highlights in the History of Avian Influenza (Bird Flu) Timeline 2020-2024

Continued here:

Current H5N1 Bird Flu Situation in Dairy Cows - CDC