Well known to herbalists, green witches, and mycophiles death caps (Amanita phalloides) has legendary status as one of the deadliest mushrooms on the planet. With their cousins the destroying angels they form the Amanita genus which has about 600 members. Their poison has had no remedy but some researchers think they have an antidote.
The genus Amanita is responsible for the overwhelming majority of mushroom poisonings worldwide and it is the main cause of food poisoning mortality. While some members of the genus are edible, most experts advise steering clear of any member of Amanita because misidentification is easy, and the consequences are severe.
Last year in October, The Children’s Hospital of Philadelphia released a statement that “In the past month, eleven cases of wild mushroom poisoning due to foraging have been reported to the Poison Control Center. Seven of these cases led to hospitalizations, including three patients who were admitted to intensive care, including one who needed a life-saving organ transplant due to exposure.”
Amanita phalloides
The death cap mushroom (Amanita phalloides) is one of the most poisonous of the genus and one of the deadliest in the world. It is responsible for more deaths than any other mushroom, and there is no known antidote. The death cap mushroom can be found in many parts of the world, including North America, Europe, Asia, and Australia. It is most commonly found in wooded areas, but it can also be found in gardens and parks.
The death cap mushroom is often mistaken for other edible mushrooms, such as the portobello mushroom. It can be difficult to identify, as it can vary in color from yellow to green to brown. The death cap mushroom has white gills and a white stem. It has a smooth, scaly cap that can be up to 6 inches in diameter. It is often mistaken for portobello mushrooms.
The death cap mushroom contains a group of toxins called amatoxins. Amatoxins are exceptionally poisonous and can cause liver failure. The most potent of these toxins is alpha-Amanitin. It is a powerful inhibitor of the enzyme RNA polymerase II (RNAP II and Pol II) that transcribes DNA into other components to create proteins. When it is locked by alpha-Amanitin the cell loses the ability to make new proteins and dies.
Symptoms of death cap mushroom poisoning usually begin 6 to 12 hours after ingestion, though few before 10 hours. Diagnosis is difficult the poisoning mimics other symptoms. After 24 hours, those symptoms include nausea, vomiting, diarrhea, jaundice, and seizures but by then supportive care stomach pumping, lavage, or activated charcoal are too late.
Around 15% of those poisoned will die within 10 days, progressing through a comatose stage to kidney failure, liver failure, hepatic coma, respiratory failure, and death. Those who survive are then at risk for liver damage requiring transplantation.
Amanita phalloides group (species comparison to scale and with geographical distribution) [Photo Credit: Danny Cicchetti CCA-SA 4.0]
There is no known antidote for death cap mushroom (or AMA) poisoning. The most reliable treatment to date is gastric lavage or stomach pumping immediately after ingestion.
A team of Australian and Chinese scientists, however, think they may have found an antidote for death cap poisoning. In a newly published article in Nature Communications, the researchers think the antidote is indocyanine green (ICG), a substance used in medical diagnostics for eye disease, cardiac function, liver disease, and measuring blood flow in the stomach.
Better still, ICG is already approved in countries including the US by the Food and Drug Administration (FDA).
To find the antidote, the researchers took human cells and edited them to break specific genes. They then added alpha-Amanitin to see which cells survived. The cells with the appropriate genes for survival then offered a clue about the nature of the molecules that could stop by alpha-Amanitin.
The next step was using an algorithm to find a substance sharing those clues in the existing database of medication. ICG fits the bill.
The team tested it on mice and found success. They wrote, “ICG is an effective antidote for treating AMA toxicity in mice.”
Whether it works in humans, time will tell. Running a study is where people are given a deadly poison followed by an antidote will have trouble getting by research ethics boards. However, the team concluded that “ICG has shown great potential for treating AMA poisoning in mice and ICG treatment can significantly attenuate AMA-induced damage in the liver and kidney, the two major AMA-targeting organs, resulting in improved survival.” It recommends “that ICG should be given as early as possible during treatment.”
Of course, the best way to avoid mushroom poisoning by any Amanita is to never eat wild mushrooms. If you are unsure about a mushroom, it is best to err on the side of caution and not eat it.
The Children’s Hospital of Philadelphia wrote “It’s easy to underestimate how difficult it is to correctly identify a poisonous mushroom. Many poisonous wild mushrooms look almost the same as wild mushrooms that are edible or the cultivated mushrooms, we buy at the grocery store and eat in our homes. In fact, sometimes they look so similar that even experienced foragers who are not experts are at risk of misidentifying a mushroom.”
They then quoted the old adage “There are old mushroom pickers and bold mushroom pickers, but NO old, bold mushroom pickers!”
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