20 Dec 2024 | 06:58 AM UTC
US: Confirmed H5N1 avian influenza cases reported in California in December /update 3
Confirmed H5N1 avian influenza cases reported in California, US, in December. Avoid contact with poultry, wild birds, and cattle.
Health authorities have reported H5N1 avian influenza cases in California, with three additional cases confirmed Dec. 2-18, bringing the total number of cases to 34 since Oct. 3. Of the confirmed cases, 33 had contact with infected dairy cattle, while the exposure source for one case remains unknown. No person-to-person transmission has been detected in the state; only animal-to-human transmission has been confirmed. The risk is currently low for the general public. However, dairy or poultry farm workers and others who work with infected animals face a higher risk. Authorities Dec. 18 declared a state of emergency to accelerate California’s response to the H5N1 outbreak following its detection in dairy cows on farms in Southern California. This declaration enables a swift and coordinated response, providing California additional flexibility in resources and operational measures to contain the virus. The state has been allocated 5,000 additional seasonal flu vaccines for those working with dairy cows in the affected areas. Health officials distributed personal protective equipment (PPE), such as N95 masks, eye protection, and gloves, to dairy farms and workers. Authorities emphasize that pasteurized milk and dairy products are safe for consumption but caution the public to avoid unpasteurized dairy products. As monitoring and testing continue, additional cases are likely. This report represents the most complete data available as of Dec. 20.
Avoid contact with wild birds and live or recently dead poultry and cattle. Practice good hygiene, wear protective equipment when handling animals, clean surfaces thoroughly, cook poultry and eggs, avoid unpasteurized dairy products, and report any illness after exposure to a healthcare provider.
Since 2022, H5N1 has spread widely among wild birds, leading to persistent outbreaks in US poultry. This year marked the first detection of the virus in cows. In August 2024, California reported an outbreak among dairy herds. The US has reported 61 confirmed human cases of H5 bird flu so far in 2024.
Avian influenza infections in humans usually occur among poultry workers, individuals in close contact with backyard poultry, or those visiting wet markets where live poultry are kept and slaughtered. There have also been cases involving individuals in close contact with infected cattle.
Avian influenza refers to diseases caused by infection with avian (bird) influenza Type A viruses, which rarely spread to humans. Many different viruses cause avian influenza, including the H5N1 subtype. H5N1 spreads through close contact with infected birds, contaminated environments, or infected cattle, and person-to-person transmission is rare. Human H5N1 infection typically has severe symptoms, including high fever, cough, sore throat, and muscle aches. The infection may progress rapidly to severe respiratory illness (difficulty breathing or shortness of breath) and neurologic changes (altered mental status or seizures).
