Current U.S. Bird Flu Situation in Humans

This is a picture of bird flu viruses with a rooster in the background.

This webpage summarizes the current avian influenza (bird flu) situation in humans in the United States.

Background

Avian influenza Type A viruses (bird flu viruses) do not normally infect people, but rare cases of human infection have occurred with some bird flu viruses. Illnesses in humans from bird flu virus infections have ranged in severity from no symptoms or mild illness (e.g., eye infection, upper respiratory symptoms) to severe disease (e.g., pneumonia) that resulted in death. Human infections with bird flu viruses have most often occurred after close or lengthy unprotected contact (i.e., not wearing gloves or respiratory protection or eye protection) with infected birds or places that sick birds or their saliva, mucous and feces have touched.

Human infections with bird flu viruses can happen when virus gets into a person’s eyes, nose or mouth, or is inhaled. This can happen when virus is in the air (in droplets or possibly dust) and a person breathes it in, or possibly when a person touches something that has virus on it and then touches their mouth, eyes or nose. The spread of bird flu viruses from one infected person to a close contact is very rare, and when it has happened, it has not led to continued spread among people. Five subtypes of bird flu viruses have infected people to cause respiratory illness (H5, H6, H7, H9, and H10 viruses). Among these, H5N1 and H7N9 viruses have caused the majority of infections in people. More information about bird flu in humans is available at Bird Flu Virus Infections in Humans.

How infected backyard poultry could spread bird flu to people graphicpdf icon[PDF - 555 KB, 2 pages]

This graphic shows how bird flu viruses can spread between infected birds and people.

Current U.S. Bird Flu Situation in Humans

  • The first case of an avian influenza A (H5N1) virus in a person in the U.S. was reported on April 28, 2022. More information about this case is available.
  • Only four human infections with low pathogenic avian influenza (LPAI)* A(H7N2) viruses resulting in mild-to-moderate illness have ever been identified in the United States.

The Current Risk to the General Public is Low

  • The detections of H5 viruses in wild birds, poultry and in one person in the United States do not change the risk to the general public’s health, which CDC considers to be low. However, outbreaks in domestic commercial and backyard poultry flocks, in addition to infections in wild birds, might place some groups of people, who may have job-related or recreational exposures to birds, at higher risk of infection. People with job-related or recreational exposures to birds should take appropriate precautions to protect against bird flu.
  • Right now, the H5N1 bird flu situation remains primarily an animal health issue. However, CDC is watching this situation closely and taking routine preparedness and prevention measures in case this virus changes to pose a greater human health risk.
  • Signals that could raise the public health risk might include multiple reports of H5N1 virus infections in people from exposure to birds, or identification of spread from one infected person to a close contact.
  • No known human-to-human spread has occurred with the A(H5N1) virus that is currently circulating in birds in the United States and globally. During past H5N1 bird flu virus outbreaks that have occurred in poultry globally, human infections were rare. Globally since 2003, 19 countries have reported rare, sporadic human infections with H5N1 bird flu viruses to the World Health Organization (WHO). Monthly case counts are available on the WHO websiteexternal icon.
  • The spread of bird flu viruses from one infected person to a close contact has occurred rarely in other countries in the past, and when it has happened, it has not led to continued spread among people.

More Information about this H5N1 Bird Flu Virus

  • USDA has publicly posted the genetic sequences of several of recently detected H5N1 bird flu viruses found in U.S. wild birds and poultry. The viruses are from clade 2.3.4.4b,** which is the most common H5N1 bird flu virus worldwide at this time. Comparing information about these newer viruses to previously circulating H5N1 bird flu viruses helps inform the human health risk assessment.
  • CDC has been comparing the properties of current H5N1 bird flu viruses to past H5N1 bird flu viruses and has found that current H5N1 bird flu viruses detected in the U.S. during late 2021 and 2022 are different from earlier H5N1 bird flu viruses.
  • So far, current H5N1 bird flu viruses lack changes seen in the past that have been associated with viruses spreading easily among poultry, infecting people more easily, and causing severe illness in people.
  • There is little information about the spectrum of illness that could result from human infections with current H5N1 bird flu viruses. At this time, only two human cases with current H5N1 bird flu viruses have been reported.
    • One infection occurred in December 2021external icon in a person in the United Kingdom who did not have any symptoms and who raised birds that became infected with H5N1 bird flu viruses. Based on information at this time, it may be that current H5N1 bird flu viruses offer less of a risk to human health than earlier H5N1 viruses.
    • The second human case was reported in the United States in April 2022 in a person who was involved in culling (depopulating) of H5N1 virus-infected poultry. The person reported fatigue and has recovered.
  • These cases do not change the human risk assessment to the general public, which CDC considers to be low.

Additional Resources

*Highly pathogenic avian influenza (HPAI) and Low pathogenic avian influenza (LPAI) are described in the Classification of bird flu viruses section.

**Clades are described in the “Classification of bird flu viruses” section.

A flock of pintail ducks flying in winter. Northern pintail ducks are among the types of birds that H5N1 bird flu virus infections have been identified in the United States in 2022.

A flock of pintail ducks flying in winter. Northern pintail ducks are among the types of birds that H5N1 bird flu virus infections have been identified in the United States in 2022.

Hand being washed with a background of virus images

Learn more about bird flu in people.

flu virus graphic

Learn more about past human infections with bird flu viruses.