Avian Influenza (Bird Flu)
Bird flu, also known as avian influenza A (H5N1) or highly pathogenic avian influenza (HPAI), is a type of influenza virus that causes highly infectious and severe respiratory disease in birds and mammals. It is causing outbreaks in poultry and dairy cows in the U.S., and some human cases have been identified in people who have had close contact with infected dairy cows and poultry. Although the current public health risk for the general public is low, the CDC and CDPH is carefully watching the situation and working with states to monitor people with animal exposures.
In October 2024, CDPH identified the first cases of bird flu in humans from people working closely with infected dairy cattle. No H5N1 cases of bird flu in humans have been identified in Riverside County at this time. The current risk to the public remains low.
Frequently Asked Questions
- What are the symptoms of a bird flu infection?
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Symptoms range from no symptoms to mild, flu-like illness to severe illness that requires hospitalization. Common bird flu infection symptoms include fever, vomiting, fatigue, cough, runny or stuffy nose, muscle or body aches, headaches, sore throat, diarrhea and eye redness or discharge (conjunctivitis). Moderate to severe illness symptoms can include shortness of breath, difficulty breathing, and altered mental state or seizures.
Most dairy workers infected in the U.S. reported mild illness, with the main symptoms being conjunctivitis or eye infection.
- How long after exposure do symptoms appear?
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People who are exposed should monitor themselves daily for signs and symptoms of new illness for up to 10 days after the last known exposure. The estimated incubation period for human infection with bird flu virus is generally three to five days but has been reported to be as long as seven to 10 days.
If you feel sick or believe you were exposed to avian flu, you should immediately isolate and notify your doctor and local public health department to get timely testing and treatment.
- How is bird flu diagnosed and treated?
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A bird flu virus infection in people cannot be diagnosed by clinical signs and symptoms alone. Laboratory testing by a local or state public health laboratory is needed to confirm bird flu virus infection in humans.
If an infection is confirmed, there is a FDA approved antiviral treatment for seasonal flu that can be used for bird flu virus infection. Antiviral treatment is recommended as soon as possible for outpatients and hospitalized patients who are suspected, probable, or confirmed cases of human infection with bird flu. Treatment should be discussed with your healthcare provider.
- How is bird flu spread to humans?
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People rarely get bird flu, but when they do, it is most often acquired through close, prolonged, and unprotected contact (no gloves, protective wear, face masks, respirators, or eye protection) with infected birds or other animals.
Human infections with avian influenza viruses can happen when enough virus gets into a person’s eyes, nose, or mouth, or inhaled. This can happen when the virus is in the air in droplets or dust and a person breathes it in or when a person touches something that has the virus on it and then touches their mouth, eyes, or nose, according to the CDC.
- How can I prevent the spread of bird flu?
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Avoid contact with infected animals, including wild birds and other animals infected with or suspected to have bird flu. Wild birds can be infected with bird flu even if they don't look sick.
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Always wash hands thoroughly with soap and water after contact with animals.
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Wear personal protective equipment (PPE) if you must work with infected animals, including respirators (N95 masks), eye protection (face shields or safety goggles) and gloves.
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Get the seasonal flu vaccine. Although the seasonal flu vaccine will not protect against bird flu, it can decrease the risk of being infected with both viruses at the same time and reduce the chance of severe illness from seasonal flu.
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Only consume pasteurized dairy products. Do not touch or consume raw milk or raw milk products, especially from animals with confirmed or suspected bird flu infection. Pasteurized milk and dairy foods are safe to consume because the pasteurization process inactivates the bird flu virus.
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- What should I do if I find a dead bird?
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It is important to avoid contact with wild or domestic birds that appear ill or have died. If you do encounter a sick or dead bird, call to report it because wildlife agencies regularly investigate reports of sick or dead animals. This type of reporting can help with early detection of illnesses such as the bird flu, or West Nile virus. Call the WNV Call Center at 1-877-WNV-BIRD or file a report online. The WNV Call Center staff will tell you how to prepare the bird for pickup or to safely dispose of it.
- Is it safe to drink milk?
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The Federal Drug Administration (FDA) has been sampling retail milk and other dairy products. To date, they have not found live, infectious virus in the products.
The CDC issued a Health Alert Network Health Advisory with recommendations that support only drinking pasteurized milk and eating dairy products made from pasteurized milk. Most of the nutritional benefits of drinking milk are available from pasteurized milk. It is important not to consume unpasteurized “raw” milk or products made from unpasteurized milk because it can contain bacteria or viruses, such as bird flu, which can cause serious illness, hospitalization, or death.