Avian Influenza (H5N1)

Avian influenza or bird flu refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses naturally spread among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Bird flu viruses do not normally infect humans. However, sporadic human infections with bird flu viruses have occurred.

If you see a bird that has been dead for less than 24 hours, please call California Department of Public Health (CDPH) at 1 (877) 968-2473 or report it online.

Avian (bird) influenza (flu) virus is a type of novel influenza virus. These viruses naturally spread among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species, including mammals. Avian flu viruses do not normally infect humans; however, sporadic human infections with avian flu viruses have occurred.

Avian influenza viruses can be classified as low pathogenic avian influenza (LPAI) viruses and highly pathogenic avian influenza (HPAI) viruses. Both LPAI and HPAI viruses have caused mild to severe illness in infected humans. Since 2022, HPAI A(H5N1) clade viruses have become widespread in wild birds in North America and have also caused sporadic human infections.

H5N1 virus is widespread in wild birds worldwide and is causing outbreaks in poultry and U.S. dairy cows, with four recent human cases in U.S. dairy farm workers (0 in California).

At this time, there are no confirmed cases of individuals who have contracted H5N1 in San Bernardino County.

Most people who get infected with avian influenza are infected due to unprotected contact with infected birds, inhaling droplets or dust from infected animals, or touching contaminated surfaces.

The CDC recommends consuming only pasteurized milk and dairy products. Unpasteurized “raw” milk can contain bacteria or viruses that cause serious illness.

Properly cooked poultry and eggs are safe to eat. The virus is killed by heat, so it’s important to cook poultry to an internal temperature of at least 165°F (74°C).

Persons with signs and symptoms consistent with acute upper or lower respiratory tract infection, conjunctivitis, gastrointestinal symptoms, or complications of acute respiratory illness without another identified cause should be evaluated for the virus. Examples of symptoms include but are not limited to:

Mild illness: cough, sore throat, fever or feeling feverish, runny or stuffy nose, fatigue, muscle or body aches, headache, conjunctivitis (red eye, discharge from eye), diarrhea, nausea, or vomiting. Fever may not always be present.

Moderate to severe illness: shortness of breath or difficulty breathing, altered mental status, seizures.

Complications: pneumonia, respiratory failure, acute respiratory distress syndrome, multi-organ failure, meningoencephalitis

People exposed to the virus should monitor themselves for signs and symptoms of illness for up to 10 days after the last known exposure. The incubation period typically ranges from three to five days but can be as long as seven to ten days, depending on various factors such as the virus strain and the route of exposure.

The CDC has a list of recommended precautions including:
• Avoiding sick or dead birds.
• Don’t touch surfaces or materials that could be contaminated.
• Use protective measures such as gloves, N95 mask and goggles.

While CDC believes the current risk to the general public is low, some people (e.g., those who work with infected or presumed infected animals) are at greater risk of infection and CDC is monitoring for changes that might indicate the potential for increased transmission of the virus to humans or among humans.

The H5N1 virus infection in people cannot be diagnosed by clinical signs and symptoms alone. Laboratory testing is needed to confirm H5N1 virus infection. Physicians should notify their state and local health departments to arrange testing and collect respiratory specimens for testing. Healthcare providers can diagnose avian flu with a throat or nose swab.

If identified early it can be treated with antiviral medications such as:
• Oseltamivir
• Peramivir
• Zanamivir
Treatment should start as soon as possible for suspected, probable, or confirmed cases.

Antiviral treatment works best when started early after symptoms begin. Antivirals can also be administered soon after unprotected exposure to prevent infection.

There are H5 candidate vaccine viruses that could be used to produce a vaccine. The U.S. is planning to produce 4.8 million doses of H5N1 avian flu vaccine for pandemic preparedness.

Avoid contact and report it to wildlife agencies for investigation. This helps with early detection of illnesses such as bird flu or West Nile virus. You can submit a dead bird report to the CA Department of Public Health (CDPH) year-round using the online form below, or you can call and report a dead bird to the WNV Call Center from April to October.


You can also report dead birds to Environmental Health Services (EHS) at https://ehs.sbcounty.gov/programs/mosquito-and-vector-control/

There are no travel restrictions related to bird flu, but travelers should avoid poultry farms and markets in affected areas, practice good hygiene, and see a doctor if they become sick during or after travel.

Dairy farmers should contact their veterinarian and state animal health officials immediately if they suspect HPAI in their herd. Prompt reporting and testing are crucial for controlling the outbreak.

DPH’s Preparedness and Response Program in collaboration with CDPH, is helping with a distribution of personal protective equipment (PPE) to farm workers who are the most at risk. Communicable Disease Section is preparing for exposure and contact monitoring in the event that an exposure is reported.

For more information, please contact the Communicable Disease Section (CDS) at (800) 722-4794 (8 a.m. – 5 p.m., Monday – Friday).