Overview

Commonly known as avian flu or bird flu, avian influenza is a disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses naturally spread among wild aquatic birds worldwide, including ducks, geese, swans, and storks, and can infect domesticated birds like chickens and turkeys. Some bird flu viruses can infect and spread to other animals as well. Bird flu viruses do not normally infect humans. However, sporadic human infections with bird flu viruses have occurred.

While uncommon, workers can be infected after unprotected exposure to infected birds/animals when enough virus gets into a person’s eyes, nose, or mouth, is inhaled, or when a person touches something that has virus on it and then touches their mouth, eyes, or nose. Animals with avian flu shed the virus in their bodily fluids.

Avian Influenza H5N1 was first seen in the U.S. in wild, migratory birds in 2015, and in agricultural poultry stock beginning in 2022. While there is currently no evidence of person to person spread, a small number of workers exposed to infected animals have been infected with H5N1. Since 2022, millions of birds have been culled because of bird flu infection in the United States. H5N1 infections in mammals have since been reported across the U.S., Canada, and other parts of the world. The 2024 infections among dairy herds were the first reported instances of H5N1 causing disease in cattle. 

People who work in operations with poultry (including eradication of sick birds), cattle and other livestock (dairy, meatpacking, etc.) and their byproducts (viscera, raw milk, etc.) should take extra precautions to reduce the risk of H5N1 exposure and illness.

People should avoid unprotected exposure to dead animals/birds, animal waste, bedding, raw milk/uncooked animal products, or materials touched by, or close to animals with suspected or confirmed avian influenza. Workers who have unprotected exposure (no gloves or other personal protective equipment) with infected animals or their products (e.g. raw milk, raw cheeses, raw eggs) are at risk of infection. This page provides information about avian influenza, including safety measures, for workers and employers who are:

• Egg or poultry farmers or processors
• Farmers, ranchers, stock handlers, and other livestock handlers or processors
• Disease control and eradication workers (including government and private sector workers)
• Animal handlers such as pet shop employees, veterinarians, or zookeepers
• Research laboratory employees

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