Avian influenza, commonly referred to as bird flu, is widespread in wild birds worldwide and is causing outbreaks in poultry and U.S. dairy cows. A few human cases have also been reported among U.S. dairy and poultry workers.
The Centers for Disease Control and Prevention (CDC) is working with individual states to monitor people with animal exposures. Visit H5 Bird Flu: Current Situation for the latest updates from the CDC.
Bird flu is just what it sounds like --- the flu, but in birds. It's caused by a version of the same virus, influenza, that causes the flu in people. Even its impact on birds is similar to that of human flu: birds may experience no symptoms, mild illness, serious illness, or, in rare cases, death.
There have been cases of mammals in the U.S., Canada, and other countries becoming infected with a version of avian influenza known as A(H5N1), or H5 bird flu. In March 2024, a human was diagnosed as having this version of the bird flu after exposure to infected dairy cows. Overall, the human case count remains low.
The spread of A(H5N1) continues to be widespread among wild birds and poultry, including outbreaks in domestic commercial and backyard poultry flocks. This has raised the risk of infection for people who work with birds and other H5 virus-infected animals.
People who catch the bird flu virus usually do so after close, long-term contact with live, domesticated poultry. This typically occurs on farms or in backyard coops. Birds infected with avian influenza viruses may shed it in their saliva, mucous, and feces. Other infected animals may shed the virus in respiratory secretions and other body fluids, such as cow milk. Human infections can happen if enough of the virus gets into a person's eyes, nose, or mouth. People can also become infected after inhaling droplets or dust that contain the virus, or touching something with the virus on it and then touching their mouth, nose, or eyes.
Symptoms can be mild to serious, and typically show up within a week to two weeks of contact with the virus. Common symptoms include:
If you experience any of these symptoms, or suspect you may have been exposed to the bird flu virus, see your healthcare provider immediately.
It is recommended that people wear personal protective equipment (PPE) when working closely with sick or dead animals, animal feces, litter, raw milk, and other such materials. The CDC offers this guide to PPE with information on what to wear and how to use it properly.
Other tips for working safely around farm animals include:
In addition to farms and other working environments, people are often exposed to germs at animal exhibits and petting zoos. Remember, even animals that appear to be healthy could be carrying germs like E. coli, Cryptosporidium, and Salmonella. It's important to take precautions, especially for people who are more likely to get sick, such as children under 5 years old, adults older than 65, pregnant individuals, and anyone with a weakened immune system.
The CDC recommends the following tips for safely visiting these types of exhibitions:
Find more safety tips at the CDC, and in the video below.
Those who work at, manage, or design animal exhibits can find prevention tips at the CDC's Resources for Animal Exhibitors.