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Mushroom poisoning, also known as mycetism, refers to deleterious effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are metabolic byproducts produced by the fungus. Mushroom poisoning is generally the result of an eater of wild mushrooms mistakenly identifying a toxic mushroom as a non-toxic or edible species. Because some poisonous fungi closely resemble commonly eaten species, mistakes may arise from misidentification based on superficial characteristics. Even very experienced wild mushroom gatherers are sometimes poisoned by eating toxic species, despite being well aware of the risks.
The safest way to avoid being poisoned is to learn species intended for picking and those to avoid.
There are many folkloric stories on defining features of poisonous mushrooms, such as:
As can be seen, folkloric stories are deceptive and therefore cannot be used as a reliable means of identification.
Persons who gather wild mushrooms should follow some practical guidelines (see mushroom hunting). In particular, they should not:
An experienced mycologist or mushroom picker will know which mushrooms have dangerous look-alikes that might cause confusion resulting in an accidental poisoning. In Europe, especially in forested regions, many people have local knowledge of one or two fungi that have been picked and eaten for generations and used in the regional cuisine. In Italy and France, for instance, several species of porcini (Italian name; cèpe in French) have been picked and enjoyed at least since Roman times. These are members of the genus Boletus, which can be identified in part by the fact that they have pores rather than gills, species for which few poisonous look-alikes exist. In some regions in Europe, mushrooms are not eaten at all; in other regions, such as Finland, Scandinavia and Russia, which traditionally have suffered from food shortage in winters, strong local knowledge on edible mushrooms exists and mushrooms form a remarkable part of cuisine. Yet many mushroom enthusiasts limit their pickings only on easily recognizable mushrooms, such as chanterelles and boletes, and leave agarics unpicked. False morel (Gyromitra esculenta) is often called the "fugu of the Finnish cuisine", and not without reason; it is deadly poisonous when raw, but rarely causes trouble if properly prepared -- though it is nonetheless considered highly toxic and its use as food is definitely not recommended by mycologists.
As mentioned, however, specimens looking similar to known edibles at home may be deadly in another place and should not be collected without good local knowledge of the biota. For instance, the tasty Cantharellus is enjoyed by many people in Scandinavia where no risk of confusing this mushroom with toxic species exists. However, in North America, this ground-dwelling mushroom has been known to be mistaken for the wood-decaying Jack O'Lantern mushroom (Omphalotus olearius), which may indeed seem to grow from the ground if there is buried wood present. Note also recent reports of confusion between Volvariella speciosa, a popular edible species in Asia, and Amanita phalloides, a deadly poisonous species in North America and Europe.
Another common problem derives from the fact that developing (newly formed) destroying angel (Amanita virosa) mushrooms very much resemble the well-known champignon, or button mushroom, the mushroom widely sold in markets and used on pizzas. Similarities between these species lead to a few deaths every decade in Scandinavia alone.
In contrast to the commonness of mushroom poisoning fatalities in Europe, such cases are far less common in North America; this may very well be directly related to the use of unwritten folk knowledge in Europe, whereas North American mushroom hunters who gather numerous species tend to refer often to authoritative reference works.
Poisoning by Amanita phalloides (the death cap) is characterized by a delay of between 6 and 24 hours from the time of ingestion to the onset of symptoms. During this time, the cells of the kidneys and liver are attacked. There is no antidote for poisoning by A. phalloides, and mortality is between 10 and 15 percent. There have been some recorded studies regarding Silybum marianum or blessed milk thistle protecting the liver from aminita toxins and promoting regrowth of damaged cells, including a study whereby 60 patients exposed to death cap poison were given 20 mg/kg of milk thistle seeds per day within 48 hours of consuming the deadly mushrooms. None of the patients died.
Serious symptoms do not always occur immediately after eating; often not until the toxin attacks the kidney, from minutes to hours later. In rare cases, symptoms leading to death may not appear for days after eating a poisonous mushroom. Symptoms typically include:
If treated promptly, death can usually be avoided. Otherwise, with some toxins, death could result within a week or a few days, if the species ingested is a potent one.
See also Category:Mycotoxins.
Three of the most lethal mushrooms belong to the genus Amanita: the death cap (A. phalloides) and destroying angels (A. virosa, and A. bisporiga); and two are from the genus Cortinarius: the deadly webcap (C. rubellus), and the fool's webcap (C. orellanus). These species cause the greatest number of fatalities. The principal toxins are alpha-amanitin in the genus Amanita and orellanine in the genus Cortinarius. Many species of Galerina, Lepiota, and Conocybe contain lethal amounts of amatoxins.
The following species may cause great discomfort, but are less often lethal.
Other causes of poisoning
Mushrooms may be rendered poisonous by insecticides or herbicides sprayed on lawns or reserves. At least one author recommends never picking them in non-natural landscapes for this reason.
Also, mushrooms are sometimes contaminated by concentrating pollutants, such as heavy metals or radioactive material (see Chernobyl disaster effects).
are believed to died from eating the death Cap mushroom.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Mushroom_poisoning". A list of authors is available in Wikipedia.|