Avian Influenza (H5N1)

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 2.3.4.4b 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).

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. If you feel sick and believe you came into contact with an infected animals in the last 10 days, contact a healthcare provider.

As recommended by the federal Centers for Disease Control & Prevention (CDC) to protect against bird flu, the California Department of Public Health (CDPH), California Department of Food and Agriculture (CDFA), and San Bernardino County are working together to support distribution of personal protective equipment (PPE).

Distribution is available for dairy farmworkers and others who handle raw milk, slaughterhouse and poultry farm workers, and animal/wildlife care centers. Dairies, poultry farms, organizations that serve workers at-risk of bird flu, or entities that provide care to sick animals can order PPE while supplies last.

To place your PPE order, please have one representative from your organization submit a request to your local Medical Health Operational Area Coordinator (MHOAC) and the San Bernardino County Department of Public Health by completing the following form: H5N1 Personal Protective Equipment Resource Request Form

Healthcare providers should consider the possibility of avian influenza A virus infection in a patient with:

• Signs and symptoms consistent with acute respiratory tract infection and/or conjunctivitis 
• A history of exposure in the last 10 days to animals or humans suspected or confirmed to have avian influenza A, or who have had exposure to raw milk. 

Symptoms
People exposed to infected animals should monitor for the following symptoms for 10 days after their last exposure:

• Trouble breathing
• Cough
• Sore throat
• Fever
• Runny or stuffy nose
• Diarrhea
• Vomiting
• Muscle or body aches
• Eye redness or discharge (conjunctivitis)
• Fatigue
• Headaches

If a person starts to feel sick, they should immediately isolate, notify their local public health department, and work with public health and health care providers to get timely testing and treatment.

The CDC recommends consuming only pasteurized milk and dairy products. Unpasteurized “raw” milk products can contain bacteria or viruses that cause serious illness. This is because the process of pasteurization kills bacteria and viruses, like avian influenza A viruses, in milk. Choosing pasteurized milk and milk products can protect your health and provide the same nutritional benefits.

All perishable foods should be refrigerated at a temperature of 40°F or colder to slow bacterial growth. Bacteria can multiply rapidly if left at room temperature or in warm temperatures.

Properly cooked poultry and eggs are safe to eat. It’s important to cook poultry to an internal temperature of at least 165°F (74°C) to kill bacteria and viruses, including avian influenza A viruses. The CDC provides tips on how to make safer food choices.

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.

If symptoms do appear, contact a healthcare provider.

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 personal protective equipment such as gloves, N95 mask and goggles.

Human infections with H5N1 are rare but unprotected contact with infected animals or their environments will increase the risk of infection. People who work with animals are at most risk for infection. If you believe that you were in contact with an infected animal or begin to feel sick, contact a healthcare provider.

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.

Healthcare providers must administer treatment. If identified early, H5N1 can be treated with antiviral medications such as:
• Oseltamivir
• Peramivir
• Zanamivir
Treatment should start as soon as possible for suspected, probable, or confirmed cases.

Treatment must be provided by a healthcare provider. 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.

If you find a dead bird, please report it to the California Department of Fish and Wildlife (CDFW) using the Wildlife Mortality Reporting Form.

Report Sick or Dead Domestic Animals: Sick and dead poultry, domestic ducks, pet birds, or livestock may be reported to the California Department of Food and Agriculture’s (CDFA) hotline at 1 (866) 922-2473.

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 highly pathogenic avian influenza (HPAI) viruses in their herd. Prompt reporting and testing are crucial for controlling the outbreak. Call the State Bird Hotline (866-922-2473) to report this.

DPH’s Preparedness and Response Program in collaboration with CDPH, is providing a one-time distribution of personal protective equipment (PPE) to farms that are the most at risk. Distribution is available for dairy farmworkers and others who handle raw milk, slaughterhouse and poultry farm workers, and animal/wildlife care centers. Dairies, poultry farms, organizations that serve workers at-risk of bird flu or some entities that provide care to sick animals can order a one-time supply of PPE.

To place your PPE order, please have one representative from your farm submit a request to the local MHOAC and San Bernardino County Department of Public Health submit a request via the following link: H5N1 Farms: Personal Protective Equipment Resource Request

Communicable Disease Section is preparing for exposure and contact monitoring in the event that an exposure is reported.

• Avian Influenza Communication Resources (cdc.gov)
• Current Situation Summary
• Information for Specific Groups
• What Causes Bird Flu Virus Infections in Humans