A recent mushroom poisoning case in Minnesota illustrates how people who set out to gather nature’s bounty can find themselves carrying home a basket of toxins, especially if they are not well versed in local species.

Following a mushroom hunting walk in Minnesota in October 2018, a forager suddenly fell ill and went into respiratory failure. The fight of his life began a couple of hours after eating mushrooms he had gathered near his workplace.

“He said this was the first time he had picked mushrooms since arriving in Minnesota in 2015 and that he had selected the mushrooms because they resembled the Ochre mushroom — Amanita hemibapha var. ochracea — from his native Burma,” according to a report published in the CDC’s Mortality and Morbidity Weekly Report.  

Poisonous mushroom Amanita muscaria var. guessowii

“A site visit to the location where the mushrooms were picked identified one remaining mushroom that matched the patient’s description (see photo at right); an MMS mycologist examined the mushroom and identified it as Amanita muscaria var. guessowii.”

The research team, which included state and federal public health scientists and researchers from the private and non-profit sectors, interviewed the patient through an interpreter. He told them how and where he had collected mushrooms. He said he took home, cooked them in turmeric, oil, and water, and ate them.

According to the patient and medical records, within two to three hours of eating the mushrooms he was at the emergency room in an altered mental state. He had vomiting, diarrhea, incontinence, sweating, excessive salivation and swollen lips and tongue. Acute respiratory failure developed quickly. He was admitted, intubated and placed on a mechanical ventilator, where he stayed for four days. In all, his hospital stay was eight days long.  

The man’s daughter was the only other person to eat any of the mushrooms he had gathered. She had similar, but milder symptoms, including mild sweating and nausea, according to the researchers’ report. The daughter was admitted to the hospital overnight for observation. She was discharged the following day. According to her father, she ate a much smaller portion of the mushrooms than he did.

An emergency room doctor recognized the man’s symptoms as likely being cholinergic mushroom toxicosis and notified the Minnesota Poison Control System. Poison control officials contacted the state health department. The ensuing investigation included work by the Minnesota Mycological Society, which was pivotal in confirming the variety of poison mushrooms involved.

The particular species the man and his daughter ate — Amanita muscaria var. guessowii — can contain ibotenic acid and muscimol. In general, the species can cause gastrointestinal symptoms. Specifically, ibotenic acid can cause central nervous system symptoms including hallucinations, agitation or seizures. Muscimol causes central nervous system depression, which can lead to a variety of complications, including respiratory failure.

Toxins in many mushrooms, including those in A. muscaria, are not deactivated by cooking.

The researchers reported the October 2018 mushroom poisoning incident has things in common with a deadly outbreak in 2006 in Minnesota that was traced to consumption of the species Amanita bisporigera. Nine people were sickened. One of them died. All were members of two Hmong families, some of whom were new arrivals in Minnesota.

“. . . the event underscored that mushroom intoxications continue to be a concern for newly arrived persons accustomed to foraging in their home countries, who might not be familiar with local mushroom ecology,” the researchers wrote. 

“Because some local toxic mushrooms might resemble edible mushrooms found in Southeast Asia, (the Minnesota Department of Health) reached out to the Karen Organization of Minnesota and sought to identify additional mushroom intoxication cases, increase awareness among community leaders, and initiate community messaging about potential dangers of wild mushroom foraging.

“No additional mushroom intoxication cases were identified. Newly arrived persons might benefit from education concerning dangers associated with and the importance of avoiding consumption of wild mushrooms.”

The researchers on the project and their affiliations were: 

  • Joanne Taylor of the Epidemic Intelligence Service of the U.S. CDC and the Infectious Diseases, Epidemiology, Prevention and Control Division at the Minnesota Department of Health; 
  • Stacy Holzbauer of the Infectious Diseases, Epidemiology, Prevention and Control Division at the Minnesota Department of Health and the 
  • Career Epidemiology Field Office Program for the Office of Public Health Preparedness and Response at the CDC; 
  • Danushka Wanduragala of the Infectious Diseases, Epidemiology, Prevention and Control Division at the Minnesota Department of Health; 
  • Alexander Ivaskovic of HealthEast Care System, Saint Paul, Minnesota; 
  • Ron Spinosa of the Minnesota Mycological Society, Eagan, Minnesota;
  • Kirk Smith of the Infectious Diseases, Epidemiology, Prevention and Control Division at the Minnesota Department of Health; 
  • Justin Corcoran of the Minnesota Poison Control System; and 
  • Ashley Jensen of the Minnesota Poison Control System.

(To sign up for a free subscription to Food Safety News, click here.)