Bird Flu (Avian Influenza A (H5N1)) January 8, 2025 Educational, Hot Topics Bird Flu (Avian Influenza A (H5N1)) Bird flu, also known as avian influenza A (H5N1) or highly pathogenic avian influenza (HPAI), is caused by a virus that primarily affects birds and mammals, resulting in their serious illness or even death. Ongoing outbreaks of H5N1 are occurring on California dairy cattle and poultry farms. The virus can also infect humans. As of January 7, 2025, there are 66 confirmed human cases in the United States, with 37 cases reported in California. 36 of those cases in California are associated with exposure to infected dairy cattle. The California Department of Public Health (CDPH) is working with local, state, and federal partners to monitor bird flu in farm animals and people who work closely with poultry and dairy cows. On December 18, 2024, Governor Newsom proclaimed a State of Emergency to strengthen California's robust response to bird flu. However, according to the CDPH, no person-to-person spread of bird flu has been detected in California and the current risk to the public remains low. Clinicians are asked to consider avian influenza A(H5N1) in patients with upper respiratory symptoms and exposure to sick/dead birds, wildlife, or domesticated animals, or exposure to unpasteurized (raw) milk or milk products. Please see County Health Advisories for additional details. Symptoms in Humans include: Eye redness or discharge Cough Sore throat Runny or stuffy nose Diarrhea Vomiting Muscle or body aches Headaches Fatigue Trouble breathing Fever (100 °F or higher) Pneumonia Seizures Transmission from sick cows, birds, or other infected animals can occur by: Breathing in dust or droplets of the virus. Splashing raw milk from an infected cow in your eyes, nose, or mouth. Touching your eyes, nose, or mouth with unwashed hands after: Touching raw milk, cow or bird feces, or other contaminated items or surfaces. Handling sick or dead animals infected with the virus. Drinking raw milk. Note: Pasteurized milk and dairy products are safe to consume. Pasteurization inactivates the bird flu virus. Resources and County Advisories Contra Costa County Provider Health Advisory Updates on H5N1 Highly Pathogenic Avian Influenza (HPAI) (December 11, 2024) Alameda County HEALTH ADVISORY Detection of Highly Pathogenic Avian Influenza(HPAI) A (H5N1) Virus in Alameda County (December 9, 2024) CDPH Health Update to Healthcare Providers (December 6, 2024)CDPH Bird Flu Webpage Centers for Disease Control and Prevention Bird Flu Tracking