California, the largest milk producer in the United States, saw cases of bird flu double in dairy herds just days apart. Officials reported on Thursday, Sept. 19, that the number of infected dairy herds stood at 17 and by Monday, Sept. 23, it doubled to 34 infected herds.
The findings are deeply troubling for a state with around 1,100 dairy herds as infected cows will now have to be quarantined and nearby dairy farms will have to undergo specialized testing.
The California Department of Food and Agriculture said that it expected more cases to be found in the coming days and weeks. However, both state and federal officials maintain that pasteurized milk is still safe to drink.
California is now second in the nation in dairy herd cases of H5N1 while Colorado is first with 64 infected herds to date. However, California did not report its first case of H5N1 in a herd until Aug. 30, far after the outbreak started in March. So far, 232 herds in 14 states have tested positive for bird flu.
Sparking even further concerns is a new warning from scientists that the virus may be evolving.
Infectious disease experts note that H5N1 could be spreading undetected in the United States because of “months of missing data” and narrow testing requirements. Right now, there is only mandatory reporting for the disease in poultry and the United States Department of Agriculture (USDA) only requires testing of lactating cows before they move across state borders.
Scientists are urging greater control measures including vaccinations, which they say may be needed “at scale” if the virus starts spreading from human-to-human.
Currently, there have only been 14 confirmed cases in humans, and it’s not been known to spread from human-to-human. The Centers for Disease Control and Prevention (CDC) contends that the risk to humans remains low but said that it is closely monitoring people exposed to the virus.
