Avian Flu

Avian Influenza

October 9, 2024

H5N1 Avian Influenza or "bird flu” is a type of influenza virus that primarily affects birds. H5N1 is also called highly pathogenic avian influenza (HPAI), based on the disease severity in poultry. H5N1 has been detected in wild and farmed birds in the US since 2022, including in Alameda County. H5N1 bird flu can also infect mammals such as cats, raccoons and skunks. Human infections are rare but can occur, especially in people with prolonged contact with infected animals.

The Alameda County Public Health Department is monitoring a multi-state outbreak of H5N1 bird flu in dairy cows in the United States, including at multiple dairies in the Central Valley of California. There are no commercial dairy cattle herds in Alameda County. Since April 2024, 17 human cases of H5N1 bird flu have been reported in the U.S., including three in California who were exposed to infected dairy cows. All three workers experienced mild symptoms. Seven of the 17 total cases were associated with exposure to sick dairy cows, and nine were associated with exposure to infected poultry. The source of the exposure in the Missouri case has not been determined. According to the CDC, the immediate risk to the general public from H5 bird flu remains low.

The Food and Drug Administration (FDA) and United States Department of Agriculture (USDA) have indicated that the commercial milk supply is safe, based on recent laboratory testing. The pasteurization process kills disease-causing germs in milk and milk products. However, the FDA does not know at this time if H5N1 can be transmitted through consumption of unpasteurized (raw) milk and products (such as cheese) made from raw milk from infected cows. For more information about how raw milk can make you sick, visit the CDC’s Raw Milk webpage. The USDA is confident that the meat supply is safe.


Please visit the CDC website for information about worker protection and personal protective equipment (PPE) for poultry or livestock farmers and other workers who could be exposed to H5N1. CDPH also has flyers about using PPE in English and Spanish. ACPHD has offered PPE to employers whose workers have contact with poultry and other wildlife. Backyard flock owners (and other Alameda County residents who may come into contact with sick, dead or infected animals, animal feces, litter, raw milk, and other materials the animal has come in contact with) can follow these instructions to order PPE.

How to protect yourself from potentially infected birds

  • Infected birds spread the virus through mucus, saliva, and feces
  • Do not handle wild birds that are sick or found dead
  • Practice good biosecurity for backyard flocks:
    • Keep visitors to a minimum
    • Do not share equipment between flocks
    • Disinfect equipment and tools
    • Avoid contact between non-domestic or wild birds and backyard flocks
  • Wash your hands before and after coming into contact with poultry
  • Do not kiss or snuggle your pet poultry
  • Keep household pets away from wild birds and their droppings
  • Wear appropriate personal protective equipment (PPE)
  • Please see CDC website for information for backyard flock owners

*Note: the seasonal flu vaccine does not protect against avian influenza

If you are exposed to sick/dead birds

  • If you were exposed to saliva, mucus, or feces from sick birds or handled any carcasses of dead birds without the use of PPE and have developed illness, seek medical attention right away.
  • Tell your healthcare about any exposures to sick/dead birds
    • Testing is recommended within the first 7 days of illness onset
  • Stay home while sick or waiting for test results
  • Treatment is available, but must be started soon after illness onset
  • Please see additional information from the CDC

If you find a sick or dead bird

  • DO NOT HANDLE SICK OR DEAD WILDLIFE
  • To report an unusual number of sick/dead birds, call the State Bird Hotline: 866-922-BIRD (2473)
  • If a dead bird is found, contact Alameda County Vector Control at 510-567-6800
  • The City of Berkeley has its own Vector Control services: 510-981-5310
  • For orphaned or injured live wild birds, contact your local wildlife rehabilitation center for advice
  • For stray or feral domestic or semi-domestic birds (e.g., peafowl, chickens, racing pigeons), please contact your local animal control or animal services for assistance

For more information

CDFA Avian Influenza
USDA APHIS Avian Influenza
CDC Information on Bird Flu
CDPH Avian and Novel Influenza Quicksheet (For clinicians)


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