Super Bloom of Death Caps Sparks Largest Outbreak of Mushroom Poisonings in Decades

After the first rains of the year, two Decembers ago, Noe and his brothers went hiking in the hills of Santa Rosa and found some mushrooms. They fried them up that evening and kicked back a few beers.

Instead of sleeping, the men spent the night dizzy, vomiting, battling diarrhea. Cramps twisted Noe’s stomach like a wet rag. At the hospital the next day, doctors told him he needed a liver transplant, and fast. If they couldn’t find a donor within a week, he would die. He was 36.

“I got scared thinking I might not see my family again,” Noe said in Spanish. He and his clinicians asked KQED not to use his last name out of concern for his health and safety. “The mushrooms here look just like the ones we used to eat in Mexico, but they just weren’t the same.”

This fall, warm temperatures and early rains fueled what fungi experts are calling a “super bloom” of poisonous mushrooms known as death caps in California. Already, 24 people have been sickened, the largest outbreak of mushroom poisonings in at least three decades. Of those who fell ill so far, 18 were hospitalized for more than a week, two needed liver transplants, and one died, prompting state health officials to take the rare step of warning the public to stop all foraging for the rest of the rainy season.

“These cases often occur in communities that may be immigrant, may not speak English, and have experience foraging for mushrooms in another country,” said Craig Smollin, UCSF emergency physician and medical director of the San Francisco division of the California Poison Control System, adding that patients from this outbreak are from Mexico, Guatemala, and China. “It’s very easy to confuse a poisonous mushroom for an edible mushroom. That’s a very easy mistake to make.”

But local mushroom experts and enthusiasts complained the state’s blanket guidance to stop foraging was overly broad and could lead to mycophobia, an irrational fear of fungi. When 14 people got sick during the last death cap super bloom in 2016, California health officials advised the public to “use caution” when foraging for wild mushrooms.

They told people to “be careful” in 2012, after a caretaker at a residential facility for the elderly in Loomis served soup made from mushrooms she picked in the backyard, accidentally killing four seniors.

“We really think that it’s a better idea to get educated about the miraculous, amazing beings these mushrooms are,” said Sita Davis, who leads foraging trips during the winter rainy season in Northern California, then spends the summer rainy season living and foraging in Mexico.

For Davis, mushroom foraging is a kind of spiritual practice, a way to commune with nature and revel in the generosity of the earth. She recommends learning about one mushroom at a time, slowly “building a relationship” with it.

One December afternoon, on a hiking trail in Oakland, she turned over logs covered in turkey tail mushrooms, clambered up side paths to stroke a cluster of oyster mushrooms, sniff the stem of an agaricus, and scrape the spongy underside of a bolete, all to demonstrate the basics of identifying mushrooms, including poisonous ones.

“What tree is it growing under? How does it smell? What’s its texture? What color is it?” she asked. “All these wonderful questions to find out if a mushroom is one that you want to bring home with you or not.”

At the top of the hill, underneath a sprawling live oak tree, Davis pawed through a mound of leaves to uncover a mushroom with a slender white stem and drooping greenish-yellow cap. There was a whole cluster of them nearby.

“We found some death caps,” she announced, aka, amanita phalloides.

They look very similar to Caesars, edible kinds of amanitas that grow in Mexico, where there is a deep cultural and culinary tradition of foraging for mushrooms, Davis said, especially among indigenous communities. One cluster of cases this fall was concentrated among Mixtec immigrants from southern Mexico now living in the Salinas Valley.

“They may be an expert in Mexico, but the knowledge doesn’t travel well because the species are different,” said Debbie Viess, co-founder of the Bay Area Mycological Society.

Bottom line, experts said, never ever eat a mushroom that you can’t identify with 100% certainty.

“That can be a deadly, deadly mistake,” Davis said.

A mistake health officials like Dr. Smollin don’t want on their hands, especially because mushroom poisoning is easily misdiagnosed — many ER doctors often confuse it with typical gastroenteritis, sending patients home prematurely and missing the chance to stem the progression of serious liver damage. Among those sickened this fall was a family of seven, including a toddler. Smollin stands by his blanket warning.

“I’d rather have the mycology community up in arms at me for coming down too hard and saying that you shouldn’t forage than have a 19-month-old who’s listed for transplant,” he said.

After his liver transplant, Noe said the same. He doesn’t eat wild mushrooms anymore, or any kind of mushroom, really.

“Just the smell of them makes me dizzy,” he said.