No.10823[Reply]
Discovery of new species of fungi occurs at a very high rate, with an estimated number of 800 new species registered annually.
It is now thought that of the approximately 100,000 known fungi species found worldwide, about 100 of them are poisonous to humans. However, by far the majority of mushroom poisonings are not fatal, and the majority of fatal poisonings are attributable to the Amanita phalloides mushroom.
Although P. porrigens is generally regarded as edible, as of 2011, it has been implicated in two documented outbreaks involving fatal encephalopathy. Both incidents were in Japan, and most victims had pre-existing kidney disorders.
The first incident occurred in September and October 2004 across nine prefectures in Japan, and involved the sickening of 59 people and the eventual death of 17. Most of those who died had pre-existing liver problems, and the average age of those affected was 70. Death occurred between 13 and 29 days after the onset of symptoms, and the onset of symptoms occurred at most three weeks after consumption of P. porrigens.
The second incident occurred in 2009, when a 65-year-old man who had been on hemodialysis died from acute encephalopathy after eating P. porrigens.
The mechanism of action for the toxicity of P. porrigens has not been definitively established, but several possibilities have been suggested. It has been demonstrated that P. porrigens contains an unusual unstable amino acid which is toxic to the brain cells of rats in cell culture studies, but it has not yet been possible to definitively determine that this was the cause of the fatal encephalopathies. Other mechanisms have been suggested for P. porrigens's apparent toxicity, including the possibility that cyanide levels in P. porrigens may be high enough to be toxic.