Number of human cases of influenza A (H5N1) in Los Angeles County: 0
See CDC: H5N1 Bird Flu: Current Situation Summary
for national surveillance data.
See CDPH: Novel Influenza for updates on the H5N1 situation in
California.
The public health risk in LA County remains low, but Public Health is closely monitoring the situation. For information on H5N1 in animals, see LAC DPH Veterinary Public Health.
For suspected human cases and non-typeable influenza A, immediately call Acute Communicable Disease Control:
- (213) 240-7941 (7:30AM-5:00PM, Mon-Fri)
- (213) 974-1234 (After Hours, Emergency Operator)
About Avian Influenza (H5N1)
Background
Avian influenza, commonly known as bird flu, refers to various strains of influenza A viruses. These viruses mainly affect wild birds but can also infect domestic birds such as poultry and pets. Some mammals may also be susceptible to certain strains, like H5N1, although they usually experience milder symptoms. There is a risk that humans could contract bird flu.
Current Situation
Over the past few years, public health departments at the federal, state, and local levels have been tracking a specific strain of Influenza A (H5N1) due to its ability to infect mammals. This includes wild animals like foxes, bears, and sea lions, as well as domestic pets such as cats and dogs. In 2022, a human case of H5N1 was detected for the first time in the United States in an individual who had direct contact with presumably infected poultry (see the full report).
More recently, in March 2024, H5N1 was detected in dairy cattle in the United States. This detection represents the first time H5 has been documented to infect cattle. In August 2024, H5N1 was detected in dairy cows in California for the first time.
There have been a small number of human infections associated with the ongoing H5N1 outbreak. Human infection with avian influenza is rare but expected. People who have direct contact with infected poultry or cattle are most at risk of infection. (see CDC's Current Situation Summary for details).
Despite these occurrences, the risk to the general public remains low. Human cases are extremely rare, and the virus typically does not spread from person to person. Those at greatest risk include individuals working with or living near infected birds or cattle.
In response, the Los Angeles County Department of Public Health is vigilantly monitoring H5N1 infections among domestic and wild birds, dairy cattle, and other mammals. The department is also collaborating with the Centers for Disease Control and Prevention (CDC) and the California Department of Public Health (CDPH) to ensure prompt identification and testing of any potentially exposed individuals who show symptoms.
Preventing H5N1
Human H5N1 infections are very rare and we're still learning about how this virus might cause infection in mammals. The following are general best practices to prevent the spread of H5N1:
- Do not eat raw milk, raw cheese and undercooked meat products.
- Avoid unprotected contact with sick or dead animals. The virus can spread to other birds, pets or mammals if they come in contact with infected feces or eat infected animals.
- Report sick or dead birds to your local animal control agency for potential collection and testing. Sick birds or animals may not have flu-like symptoms, but may appear generally sick, have difficulty moving, seizures, or be found dead.
- Anytime you are in contact with animals, wash your hands with soap and water before touching your face or eyes.
- If you work with or around sick animals, use appropriate personal protective equipment.
- Prevent wild birds from getting into areas that house pet birds or poultry. Also make sure wild birds cannot defecate down into areas holding pet birds or poultry.
- Take down bird feeders and shared bird baths to reduce the risk of the virus spreading from bird-to-bird.
- Keep pets away from sick and dead birds as there is some risk of the virus spreading to dogs, cats and other wild mammals if they eat raw or uncooked poultry.
- Do not feed raw milk or raw milk products to pets.
- Get a seasonal flu vaccine. Seasonal flu vaccination will not prevent infection with avian influenza viruses but can reduce the risk of getting sick with human and bird flu viruses at the same time.
Information for the Public
Information for Physicians and Healthcare Providers
Providers should be vigilant in evaluating patients presenting with influenza-like illness (ILI) or acute respiratory infection (ARI) symptoms who have had recent direct or close contact with birds or dairy cattle.
Suspected cases of novel influenza A virus infection warrant immediate collection of respiratory specimens.
Testing for H5N1
LACDPH is following CDC guidance to enhance influenza surveillance due to the ongoing global outbreak of Influenza A (H5N1). Additional actions for clinical laboratories are as follows:
- If a patient has symptoms of influenza-like illness and recent exposure to birds, livestock, or raw milk, call LAC DPH at 213-240-7941.
- If requested, submit remnant, previously tested Influenza A/B positive molecular specimens to the Public Health Lab for additional testing.
- Immediately report to LACDPH (call 213-240-7941) any clinical specimen for which subtyping is attempted and does not identify a seasonal subtype. These specimens should be urgently directed to the Public Health Lab for further testing.
For complete details, see the LAC DPH Laboratory Alert Notification.
- Commercially available rapid influenza diagnostic tests and most influenza molecular assays do not distinguish between infection with seasonal influenza A viruses and avian influenza A viruses.
- While some diagnostic assays may detect the presence of some novel influenza A viruses, a negative result should not be used to rule out novel influenza A virus infection when testing possible human cases.
- Clinicians are advised to consider testing for other respiratory pathogens, such as SARS-CoV-2, given the rarity of human novel influenza A virus infections.
- Testing symptomatic human cases of suspected novel influenza A virus infection should be performed at a public health laboratory.
PPE
Clinicians working with potential human H5N1 cases should adhere to Standard Precautions plus Contact and Airborne Precautions, including:
- Hand hygiene
- Gloves
- Gowns
- Respiratory protection
- Eye protection
- Eye protection (i.e., goggles or a face shield) should be worn at all times when evaluating patients for H5N1 infection.
- Patient placement
- Confirmed or suspected cases should be placed in an airborne infection isolation room or a private room.
For more information, see the CDC’s Interim Guidance for Infection Control within Healthcare Settings.
Evaluation
In patients presenting with respiratory symptoms, assess for recent history of recreational or occupational exposure to wild or domestic birds or dairy cattle, especially in the setting of a known outbreak. Since other mammals can become infected with H5N1, it is also advisable to ask patients about other animal exposures.
Human illnesses with H5N1 bird flu have ranged from mild (e.g., eye infection, upper respiratory symptoms) to severe illness (e.g., pneumonia) that have resulted in death in other countries.
Reporting Suspected Cases
All healthcare reporters should immediately report suspected human cases of bird flu or influenza A non-typable to Acute Communicable Disease Control by calling:
- (213) 240-7941 (7:30AM-5:00PM, Mon-Fri)
- (213) 974-1234 (After Hours, Emergency Operator)
In the event of a patient with ILI or ARI symptoms and a recent exposure to birds, cattle, or raw milk, a respiratory specimen should be collected immediately and sent to CDPH for testing.
Resources & News
Resources
- LAHANs
- LAC DPH Laboratory Notification: Enhanced Influenza Surveillance (June 13, 2024)
- CDC: H5N1 Bird Flu: Current Situation Summary
- CDPH: Wastewater Surveillance for Influenza A Viruses FAQs
- CDC's Interim Guidance for Infection Control Within Healthcare Settings When Caring for Confirmed Cases, Probable Cases, and Cases Under Investigation for Infection with Novel Influenza A Viruses Associated with Severe Disease
- Veterinary Public Health H5N1 Page
- USDA: Highly Pathogenic Avian Influenza (HPAI) Detections in Livestock
News
CDPH Confirms Two Cases of Bird Flu in California (October 3, 2024)
Avian Influenza Confirmed in Three California Dairy Herds (August 30, 2024)
CDC Confirms Three Human Cases of H5 Bird Flu Among Colorado Poultry Workers (July 25, 2024)
CDC Confirms Human Cases of H5 Bird Flu Among Colorado Poultry Workers (July 14, 2024)
CDC Reports Fourth Human Case of H5 Bird Flu Tied to Dairy Cow Outbreak (July 3, 2024)
CDC Confirms Second Human H5 Bird Flu Case in Michigan; Third Case Tied to Dairy Outbreak (May 30, 2024)
CDC Reports Second Human Case of H5 Bird Flu Tied to Dairy Cow Outbreak (May 22, 2024)
U.S. Case of Human Avian Influenza A(H5) Virus Reported (April 28, 2022)
Highly Pathogenic Avian Influenza A (H5N1) Virus Infection Reported in a Person in the U.S. (April 1, 2024)