https://www.sfchronicle.com/health/article/h5n1-avian-flu-san-francisco-19489217.php San Francisco Chronicle LogoHearst Newspapers Logo Skip to main content [ ] Subscribe Home Insurance Bay Area * San Francisco * Transit * Crime * Drug Crisis * Golden Gate Park * COVID-19 * Health * Data Spotlight * PG&E * Season of Sharing * Housing Crisis * Total SF Weather * Weather Forecast * Air Quality Tracker Climate * Drought * Fire Tracker * Quake Tracker * Wildfires Food * Top Restaurants * Restaurants * Restaurant Closures * Top Wineries * Wine, Beer & Spirits Sports * Giants * Warriors * 49ers * A's * High School * Bay FC * Women's Sports * College Politics * Election 2024 Opinions * Chronicle Editorial Board * Letters to the Editor Real Estate * Find a Home * Commercial Real Estate California * Tahoe Tech Datebook U.S. & World Travel * Outdoors Vault: Our S.F. 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The San Francisco Department of Public Health reported that state health officials discovered the infected, asymptomatic birds during a routine monitoring program conducted by the California Department of Food and Agriculture. The testing comes amid the current national bird flu outbreak. "The most important thing to note is there is no threat to public health at this time," said Dr. George Han, the Director of Communicable Disease Prevention & Control at the San Francisco Department of Public Health. "There have been no human cases." Advertisement Article continues below this ad Health officials said they closely monitored the market employees who had contact with the chickens. Over 10 days, none of the employees reported symptoms. No public exposure occurred, and the market has since reopened safely. "Essentially, when there is an emerging virus we work in the background to do our due diligence so that if there is a potential threat to human health we are on top of it," Han said. In response to the bird market detection, WastewaterSCAN, a national initiative monitoring infectious diseases through municipal wastewater, began testing San Francisco's wastewater for H5N1. Initial tests detected fragments of H5N1 genetic material, making San Francisco the only municipality in California with a positive avian flu detection. More For You Officials investigate unusual surge in flu viruses in Northern California The Bay Area has become a hotspot for influenza A viruses, with moderate to high increases... California budget cuts for public health could hamper bird flu tracking Though the risk to human health is currently low, the avian virus has the potential to... However, follow-up tests later in May showed no H5N1 fragments. Advertisement Article continues below this ad The agency said it is investigating the origins of these genetic traces, with consideration of the city's unique combined sewer system, which treats both wastewater and stormwater. "It's a unique thing," Han said. "We take in everything that goes into the storm drains, including any animal waste from birds or any other animal." An increase in flu viruses detected at wastewater treatment plants in California in recent weeks has sparked concern that the H5N1 bird flu may be spreading more rapidly than anticipated, potentially putting the state's 1.7 million dairy cows at risk for infection. Health officials have observed multiple spikes in influenza A viruses, which include the H5N1 avian flu strain that has killed millions of birds worldwide and infected dozens of dairy cow herds across nine U.S. states. "We are definitely taking this seriously. This is the first time we are seeing avian flu in cows. We hadn't seen that previously," Dr. Mandy Cohen, director of the Centers for Disease Control and Prevention, told the Associated Press. "The fact that it is in cattle now definitely raises our concern level." Advertisement Article continues below this ad The Bay Area, in particular, is a hotspot for flu activity, according to data from approximately 700 sites published by the Centers for Disease Control and Prevention. Nearly all monitored facilities in the region show moderate to high increases in influenza A viruses. However, Han said San Francisco hospitals have not observed an increase in individuals with undiagnosed upper respiratory illnesses. "Our levels, as far as we can tell, have not increased significantly in recent weeks," he said. Though avian flu poses minimal risk to humans, its spread among livestock could disrupt food supplies and potentially lead to a pandemic if it mutates to allow human-to-human transmission. No cases of infected herds have been reported in California. Justin Sullivan/TNS Though the avian flu poses minimal risk to humans, its spread among livestock could disrupt food supplies and potentially lead to a pandemic if it mutates to enable human-to-human transmission. Advertisement Article continues below this ad As of now, no cases of infected herds have been reported in California, the leading milk-producing state in the U.S., with around 1,300 dairy farms. The current strain of avian flu emerged among birds in 2022 and was first detected in dairy cows in the United States in late March, marking the first known instance of bird flu viruses in cows. "It's not a new strain of the virus," Cohen said. "So this is known to us. We've been studying it. And, frankly, we've been preparing for avian flu for 20 years." Since then, it has spread to 49 herds of dairy cattle across nine states: Texas, Michigan, Kansas, Colorado, Idaho, New Mexico, North Carolina, South Dakota and Ohio, according to the Department of Agriculture. There have been only four reported cases of avian flu infection in people in the United States. One case occurred in Colorado in 2022 and involved an individual who worked closely with infected poultry. The other three cases were more recent -- one in Texas in March and two in Michigan last month -- and involved people employed at dairy farms. Advertisement Article continues below this ad More concerning, the current strain of bird flu has developed numerous mutations, according to a new study, that may increase its ability to spread between species and reduce its susceptibility to antiviral drugs. "This is a new development," Cohen said. "Cows, mammals being a reservoir gives this virus a new opportunity to change. That's what we're watching for really closely." Han said there is no cause for concern in San Francisco for now. "The reason we're talking about this is to be transparent about the work that we in public health do daily," he said. "There are experts who are working on this and looking at this to ensure that if anything changes in these new developments, we'll be right there, ready to spring into action." Here are some answers to commonly asked questions about the risk of avian influenza, according to the Centers for Disease Control and Prevention, United States Department of Agriculture and local health authorities. Can people get sick from H5N1? Yes; although rare, people can get infected with H5N1 through direct contact with infected birds or contaminated environments. What are the symptoms of H5N1 in humans? Symptoms include fever, cough, sore throat, muscle aches and, in severe cases, respiratory difficulties and pneumonia. "So far, the cases involving humans have been very mild," Han said. How does H5N1 spread? H5N1 spreads primarily through direct contact with infected birds, their droppings, or contaminated surfaces. It does not usually spread from person to person. How can I protect myself from H5N1? Avoid direct contact with wild birds and poultry that appear ill. Practice good hygiene, including regular hand washing and using alcohol-based hand sanitizers. "People should continue everyday common sense practices, like drinking pasteurized milk, preparing their meat properly, not going near wild animals," Han said. Is there a vaccine available for H5N1? Vaccines are primarily used for high-risk groups such as poultry workers and are not generally available to the public. Should I avoid public parks with bird populations? No, but avoid touching birds in the wild and their droppings, and wash hands thoroughly if you come into contact with surfaces that may be contaminated. What should I do if I find a dead bird? Do not touch it. Report it to local animal health authorities who can safely remove and test the bird for avian influenza. Can I still eat chicken or duck? You can still eat poultry safely. Ensure it is cooked to an internal temperature of at least 165degF (74degC), which kills the virus. Is it safe to keep pet birds? Yes, but practice good hygiene, regularly clean cages, and monitor the health of your birds closely. Do I need to wash my hands after filling a bird feeder? It is recommended to wash your hands after filling a bird feeder to reduce any risk of infection from wild bird droppings or contaminated surfaces. Reach Aidin Vaziri: avaziri@sfchronicle.com June 3, 2024|Updated June 3, 2024 12:35 p.m. Aidin Vaziri Staff Writer Aidin Vaziri is a staff writer at The San Francisco Chronicle. Top of the News San Francisco Fred Again.. and Skrillex's 'rave' in front of S.F. City Hall ends mid-song as the duo hit curfew The two superstar DJs were in mid-song during the outdoor San Francisco concert just as the clock struck 10 p.m. and the city's strict curfew took effect. 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