Lethal mushrooms picked in the California wilderness poisoned 14 people late last year, with three requiring liver transplants, including an 18-month-old girl.
The cases were reported to the California Poison Control System over a two-week period in December, although the Centers for Disease Control and Prevention (CDC) didn't announce the incidents until Friday. The poisonings were included in the Morbidity and Mortality Weekly Report.
The mushroom is known as the "death cap," or Amanita phalloides, a fungus responsible for more than 90% of the world's mushroom-related deaths. The CDC said they pose "serious public health concerns" and urge freestyle foragers to have an expert inspect their harvest before eating.
The death cap contains a toxic agent and as little as one mushroom can carry a fatal dosage. In many of the incidents in California, patients reported eating multiple mushrooms.
In 2016, the state noticed an uptick in wild mushroom poisonings as well as an abundance of wild mushroom growth brought on by rain and warm temperatures.
The cases involved patients picking the mushrooms for themselves while others received the mushrooms from another person. It typically took several hours for the patients to develop gastrointestinal issues such as nausea, vomiting and dehydration.
Those affected ranged in age from 18 months to 93 years old. A 37-year-old man picked and ate one mushroom in Santa Rosa, north of San Francisco, and felt symptoms 10 hours later. A group of five people all got sick, including the 18-month-old girl, after all ate wild mushrooms picked by a stranger in the mountains.
Eleven of the patients recovered and three required liver transplants.
In 2012, four people died at a Northern California senior care facility after all ate a soup made from poisonous mushrooms.
The CDC said an antidote to the death cap is licensed in most of Europe and is currently being evaluated in the United States.
In the meantime, the agency asks people to be careful when picking and eating mushrooms. Before eating, mushrooms should first be examined, identified and reviewed by a mycologist, someone who studies fungi.