A dozen more dairy herds in California have been stricken with bird flu as the virus continues to infect animals and humans around the U.S.
Nearly 700 herds in the state — or 71 percent of all herds — have caught H5N1 since late August, forcing Governor Gavin Newsom to declare a state of emergency and the government to announce new testing.
While California, the nation’s top milk-producing state, has the most infections in dairy herds, more infections were reported in Michigan, and the number of confirmed human cases has inched closer to 70, according to health officials.
Last week, the Centers for Disease Control and Prevention said that the virus had likely mutated in a Louisiana patient who had contracted the country’s first severe case of the illness.
Mutations could allow the virus to better bind to nerve endings in the respiratory tract to initiate infection, although scientists say this is not yet a cause for alarm. Generally, cases have been mild in humans.
While experts worry H5N1 will eventually mutate into a lethal strain capable of human-to-human transmission, authorities assert that the current risk to population health remains low. Human-to-human transmission has not yet been reported.
A December study published in the journal Science found that the virus strain found in dairy cows in the U.S. may only need a single mutation for it to be able to spread among humans, the American Veterinary Medical Association noted in a Monday report.
“The longer this virus circulates unchecked, the higher the likelihood it will acquire the mutations needed to cause a pandemic. We need to act urgently to prevent this scenario,” Dr. Les Sims, former assistant director of the Department of Agriculture, said in a statement shared by the organization.
Bird flu has also been found in pigs, migratory birds, and West Coast cats that drank raw milk and ate recalled pet food. Outbreaks have been detected in all 50 states since 2021, according to agriculture officials. Bird flu infections in poultry have resulted in rising egg prices.
In response, the Department of Agriculture is conducting trials for vaccines for poultry and dairy cattle. Vaccination, however, can complicate distinguishing between vaccinated animals and those naturally infected. Still, Sims says that the virus has “fundamentally changed the way we need to think about managing avian influenza.”
“The stakes are too high for complacency,” he said. “We must act now to protect animal health, safeguard our food systems, and avert a potential pandemic.”
