H5N1 bird flu

Last content update: 10/3/24

The County of Santa Clara Public Health Department is monitoring a multi-state outbreak of H5N1 bird flu in dairy cows in the United States. This is the first time that H5N1 bird flu has been found in cows and transmission from cows to humans has been reported. H5N1 bird flu was first detected among cows in California in August 2024. H5N1 bird flu was first detected among humans in California in October 2024.

To date, there have been no reported cases of H5N1 bird flu in cows or humans in Santa Clara County.

For more information, including the number of reported H5N1 cases in cow herds and the number of reported human H5N1 cases in California and the rest of the United States, visit the CDC’s H5 Bird Flu: Current Situation Summary webpage.

What is H5N1 bird flu?

H5N1 bird flu is a specific strain or subtype of influenza virus that is widespread in wild birds. H5N1 bird flu is also called highly pathogenic avian influenza (HPAI). H5N1 bird flu can infect birds, poultry, and some mammals such as cows, cats, and humans. There is no known human-to-human spread of H5N1 viruses. Human cases caused by contact with infected animals are rare, but spread of the virus may lead to changes that make it more likely to infect humans or enable it to spread from human-to-human.

What is the Public Health Department doing?

Sharing information

The County of Santa Clara Public Health Department is working with health and agriculture partners at the local and state level to ensure stakeholders get accurate information to best protect the health of the community. The Public Health Department shares information with agricultural workers on how to identify sick animals and protect themselves from infection. This is part of the Department’s ongoing work to ensure community safety by preparing in advance for various diseases, even before there are cases here.

Testing and monitoring for presence of H5 influenza

The Public Health Department is collecting human influenza samples from healthcare facilities for further testing. This testing can identify if samples contain H5 influenza or a common human influenza strain. As of the latest update, there have been no H5 influenza detections in these human samples from healthcare facilities in Santa Clara County.

The Department is also monitoring wastewater testing results from the national WastewaterSCAN program. There have been sporadic detections of H5 influenza in wastewater samples taken from sewersheds in Santa Clara County since June 19.

To view data on wastewater testing for the H5 influenza subtype in the four Santa Clara County sewersheds, refer to the WastewaterSCAN Dashboard. For data on the level of all influenza virus detected in wastewater in Santa Clara County, refer to the Respiratory virus data dashboard. These dashboards indicate the level of influenza virus particles present in wastewater, but do not indicate how the virus was introduced into the wastewater.

What can you do?

CDC has indicated that the current risk to the general public from H5N1 bird flu is low. People should follow these recommendations:

Food safety

Do not prepare or eat unpasteurized (raw) milk or raw cheese. Raw milk and cheese have not gone through a process called pasteurization that kills disease-causing germs. For more information about how raw milk can make you sick, visit the CDC’s Raw Milk webpage.
Cook beef and poultry products, including eggs, to the right temperature. For more information on minimal internal temperatures, refer to the CDC’s instructions on preparing and consuming food.

Avoid contact with wild birds and sick or dead animals

Avoid contact with wild birds and keep pets away from wild birds.
Avoid surfaces that may be contaminated with bird feces.
Avoid unprotected exposures to sick or dead animals. If you find a sick or dead animal, do not attempt to touch or handle the animal with bare hands or clothing.
- Report dead birds to the California Dead Bird Hotline at (877) 968-2473.
- For other dead animals, contact your local animal control authority.

If you have job-related or recreational exposure to infected animals, including wild birds, poultry, and dairy cows, you are at greater risk of being exposed to H5N1 bird flu. These jobs may include farmers or workers on poultry and dairy farms, slaughterhouse workers, backyard bird flock owners, veterinarians and veterinary staff, and emergency responders. In addition to the recommendations above, you should:

Call your doctor if you feel sick. Symptoms of H5N1 bird flu can include cough, sore throat, fever, and red or watery eyes.
For workers: Follow all CDC recommendations for worker protection to reduce risk of infection.
For backyard flock owners: Follow the U.S. Department of Agriculture (USDA) Defend the Flock recommendations. If you think birds in your flock may have bird flu, follow CDC recommendations to protect yourself.

Need a doctor or health insurance? Call the County's Patient Access Department at 1 (866) 967-4677 or drop in at 770 S. Bascom Ave. San Jose, CA 95128.

Learn more

For more information on H5N1 bird flu, refer to the CDC’s H5 Bird Flu: Current Situation Summary webpage.

Educational flyer for agricultural workers

The Public Health Department has also created this educational flyer for agricultural workers about H5N1 bird flu. Please access the PDF below: