More mushroom poisoning cases reported in California in biggest U.S. outbreak ever

California’s spate of mushroom poisonings, which has killed four people and hospitalized 43 others, is the largest known outbreak of its kind in U.S. history, experts say.

California’s monthslong spate of mushroom poisonings, in which four people have died and 43 others hospitalized, has become the largest known outbreak of its kind in U.S. history, experts say.

Subscribe to read this story ad-free

Get unlimited access to ad-free articles and exclusive content.

Three cases were reported earlier this week, long after the typical growing season for the mushrooms behind the illnesses, leaving public health officials and mycologists puzzled about why the poisonings have been so widespread and what is causing the trend.

The three newest cases were among a family that had picked mushrooms in Napa County on Saturday, became sick Sunday and was hospitalized at Stanford Medical Center, according to Dr. Christine Wu, Napa County’s public health officer.