The amount of mushroom poisonings and the number of people affected doubled this past year in China compared to 2019.

In 2020, the number of investigations reached 676, involving 102 species of poisonous mushrooms, 24 of which were newly recorded in China.

Mushroom poisoning incidents from 24 provincial-level administrative divisions involved 1,719 patients and 25 deaths. In 2019, 276 incidents involved 769 patients and 22 deaths.

In 2020, the number of cases ranged from one to 27, and 14 outbreaks involved more than 10 patients. Most incidents were reported in Hunan, Yunnan, Guizhou, Zhejiang and Sichuan. Of these, 93 patients from 24 incidents had eaten poisonous mushrooms purchased from a market or given by friends; 51 people from 12 outbreaks had been poisoned after eating dried mushrooms; and 404 patients from 131 incidents with seven deaths ate mixed mushrooms. Experts in the China CDC Weekly journal strongly advised people to avoid having mixed wild mushrooms and alcohol.

Main types behind intoxication
There were also more occasions when patients consumed a combination of poisonous mushrooms, which increases difficulty and risk for diagnosis and treatment because of the different symptoms.

Like in 2019, mushroom poisonings occurred in every month but mainly from June to October. There were two peaks in June and September involving 428 and 412 patients, and eight and three deaths, respectively.

The most lethal species of those identified were Lepiota brunneoincarnata with five deaths and Russula subnigricans, and Amanita subpallidorosea with four deaths each. Chlorophyllum molybdites caused the most poisonings, being mentioned in 154 incidents with 304 patients.

Lepiota brunneoincarnata, the most dangerous species in 2020, was responsible for 15 incidents, 29 patients, and five deaths as the lone cause or in combination with other species.

A total of 56 species causing gastroenteritis were identified from intoxications in 2020. Among them, Baorangia major, Chlorophyllum demangei, Entoloma caespitosum, Gymnopus densilamellatus, Lactarius atromarginatus, Lactifluus deceptivus, Micropsalliota furfuracea, Neonothopanus nambi, Pulveroboletus subrufus, Russula rufobasalis, and Tricholoma stans were newly discovered as lethal and were added to the poisonous mushroom list.

Controlling the problem
Another 28 species causing psycho-neurological disorders were linked to incidents including Clitocybe subditopoda, Gyromitra venenata, Mallocybe fulvipes, and Pseudosperma yunnanense, which were new species added to the poisonous mushrooms list.

Gyromitra venenata was discovered in incidents in the Yunnan and Guizhou provinces and were the first reported poisonings because of gyromitrins in China since 2000. The rare poisoning Shiitake mushroom dermatitis was also reported. Hemolysis poisoning caused by Paxillus involutus was recorded for the second time since the beginning of this century, resulting in one death in Inner Mongolia.

Epidemiological investigations, timely and accurate species identification, toxin detection, and appropriate diagnosis and treatment are key to control mushroom poisoning, said researchers.

“The growing number of poisonous mushroom identifications suggests that what we know only a portion of the variety of poisonous mushrooms. Many species need to be formally described and their edibility is not clear,” they said.

“Promoting knowledge about safe consumption of mushrooms is essential to reduce mushroom poisonings. It is not wise to collect and eat wild mushrooms.”

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