For Immediate Release:

November 1, 2024

H5 Avian Flu Detected at Wastewater Sampling Site in Los Angeles County, Public Health Closely Monitoring Situation 

Risk Remains Low

The Los Angeles County Department is investigating possible sources of H5 avian flu, which has been detected at low levels for the first time at one of the wastewater sampling sites in Los Angeles County.  

H5N1 is one type of avian influenza that has been spreading among birds and mammals, leading to a nationwide outbreak. There are no reports of human H5N1 cases in Los Angeles County and the overall risk of H5N1 to LA County residents remains low. There is no evidence of sustained human to human transmission of H5N1 in the United States.

Public Health is actively engaging key risk groups such as dairy and meat processing sites to identify possible sources of H5 avian flu in wastewater. The virus may have been introduced into wastewater by discarded contaminated animal products, infected wild bird droppings entering the sewage system, or animal infection. Public Health routinely monitors and tests symptomatic birds, pets, and wild mammals in LA County for H5N1 through our Public Health Laboratory.    

Wastewater sampling is routinely performed as part of ongoing surveillance for infectious diseases including H5N1. H5 has previously been detected in wastewater in both northern and southern California. The virus has been detected in more than 200 dairies in California and there have been 16 human cases of avian flu in California. Public Health, in conjunction with the California Department of Public Health (CDPH), the Centers for Disease Control and Prevention (CDC) and state and federal agriculture agencies, has been tracking the situation closely.

While the current risk of transmission to LA County residents is low, Public Health encourages residents to follow these best practices when around animals or when consuming animal products:

• Do not eat raw milk, raw cheese, and undercooked meat products.
• Avoid unprotected contact with sick or dead animals, or materials contaminated with bird feces. The virus can spread to other birds, pets or mammals by contact with infected feces or consumption of infected animals.
• Avoid handling wild birds and observe them only from a distance. If you have to handle wild birds, even if they appear healthy, practice good hand hygiene and consider wearing a well-fitting mask. Some birds may carry the virus but appear to be healthy.
• Report sick or dead birds to local animal control agency for potential collection and testing. Sick birds or animals may not have flu-like symptoms, but instead may be unable to fly, have seizures, have difficulty walking or be found dead.
• Prevent wild birds from getting into areas housing pet birds or poultry. Also make sure wild birds cannot defecate down into areas holding pet birds or poultry.
• Take down bird feeders and communal bird baths to reduce the risk of the virus spreading from bird-to-bird.  
• Residents should also keep pets away from sick and dead birds. There is some risk of the virus being transmitted to mammals such as dogs, cats, and wild mammals, especially if they eat infected, uncooked birds.  
• It is especially important that people who may have exposure to infected or potentially infected birds or other animals 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.

About H5N1

Avian flu refers to various strains of influenza A viruses that typically infect birds. While these viruses mainly affect wild birds, sometimes they also infect other animals, including wild and domestic animals (including seals, foxes, cats, and cows). H5N1 is one type of avian influenza that has been spreading among birds and mammals, leading to a nationwide outbreak. This is the first time these bird flu viruses have been found to be spreading in cows.

Signs/symptoms of H5N1 virus infection in humans may include:

• Cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue
• Fever* or feeling febrile
• Eye redness (or conjunctivitis)
• Shortness of breath or difficulty breathing
• Diarrhea, nausea, vomiting

*It is important to note that infection with influenza viruses, including novel influenza A viruses, does not always cause fever. Fever may not occur in infected persons of any age, particularly in persons aged 65 years and older or people with immunosuppression.

For questions or to find a nearby clinic or doctor, residents can call the Public Health InfoLine at 833-540-0473. Open every day from 8 a.m. to 8 p.m.

For more information, visit our websites:

Avian flu in animals: publichealth.lacounty.gov/vet/HPAI.htm

Avian flu in humans: ph.lacounty.gov/acd/diseases/h5n1.htm