Poisoning by fungi

Poisoning by fungi

On average, a quarter of “mushroom accidents” in France come from mushrooms picked up on the family property

Just because no one in your family has ever had anything from eating them before, doesn't mean that all the mushrooms that grow in your garden are good and you can give them to the neighbors as well. 

Did you know that French law prohibits individuals from selling or offering mushroom picking?

Poisoning is caused by fungi that are poisonous by definition, either through ignorance or confusion. 

Under a mushroom cap, the reproductive part is made up either of stings, or tubes, pores, or even folds or more often than not lamellae. 

In the case of amanita, for example, the insertion and the color of these mature lamellae are essential for the determination, and therefore the recognition of toxic or lethal species.

But sometimes accidents advance knowledge because no one had ingested this fungus before. 

Edible mushrooms are not without risk even if they are collected healthily in a healthy place, with appropriate cooking. 

Indeed, if you transport your harvest in plastic bags, your mushrooms can become very humid, mold will then develop on their surface and their decomposition will be accelerated. 

In addition, some species become toxic on contact with plastic: perfect edibles can thus become unfit for consumption, especially if the consumer has a gastric deficiency. 

Ditto with fresh mushrooms sold in stores, which would have been poorly preserved since their harvest.

During your visits to mycological exhibitions, you have undoubtedly noticed labels with the mention "To reject" for certain mushrooms. 

If there is no ambiguity on the mushrooms displaying a skull, the collector is worried by the mention “To reject”.

In general, mycologists will answer you that they are mushrooms with a strong odor or bad taste (acrid, bitter), or that this species has no culinary interest or can be confused with a toxic or even deadly double. . 

Allergies can still be possible in different individuals, and in some cases they can prove fatal. 

More than ever, caution must be exercised.

Some species, when consumed in too large quantities, can cause poisoning. 

This is true even for the best of edibles: an "overdose" of porcini mushrooms, chanterelles or trumpets can lead to indigestion, your brain will remember this annoying incident and you will become intolerant to these fungi. 

Clearly, you will never be able to consume ceps, chanterelles or trumpets for life. So consume the best edibles always sparingly.

Mushrooms are rich in chitin, a nitrogen derivative that is also found in the cuticles (shells) of insects and which is very difficult to digest. 

They also have an abundance of specific sugars: trehalose and mannitol. 

The first sugar can only be broken down by trehalase, an enzyme unfortunately missing by genetic deficiency in some individuals. 

In this case, the accumulation of trehalose leads to fermentation responsible for significant diarrhea. 

The second sugar induces a high osmotic pressure, responsible for sometimes violent intestinal debacles. 

The very active metabolism of fungi is also responsible for the synthesis of certain complex molecules (antibiotics, etc.) to which certain organisms are allergic or intolerant. 

It is therefore understood that the excessive consumption of perfectly edible mushrooms can induce, particularly in certain people, reactions of intolerance which are sometimes very violent and spectacular.

We bring to your attention a new website presenting hundreds of photos of mushrooms, in order to help and inform walkers about the different species: http://www.champiweb.com

Article Sciences et Avenir – November 2022 – “The origin of mushroom toxicity has been identified.”

Sciences & Vie article – November 2023 – “Why are some mushrooms toxic?”

Article in English (October 2022): “Amanitin biosynthesis genes in Amanita rubescens”

Here is a brief overview of the main poisonous and deadly fungi (photo credit: Eric MICHON, member of the SHNVC - Société d'Histoire Naturelle de Voiron et de Chartreuse).

Poisonous fungus: Amanita muscaria - Fly killer

Amanita muscaria =  Fly agaric

This amanita is poisonous, potentially fatal.

Poisonous Mushroom: Amanita phalloïdes - Phalloïde

Amanita phalloïdes = Amanita phalloïde

This deadly mushroom is absolutely worth knowing.  

For an adult, a single hat can be fatal!

Poisonous Mushroom: Amanita pantherina - Panthere

amanita pantherina  = Amanita panther

This dangerous fungus can be confused with other edible amanita.

Poisonous Mushroom: Omphalotus illudens - Clitocybe of the olive tree

Omphalotus illudens = Clitocybe of the olive tree

Too often confused with chanterelles, the “tufted” aspect, the presence of real blades and the bright color should encourage abstinence. 

Note that Omphalothus olearius grows at the foot of olive trees, but O. illudens is sometimes found at the foot of oak or chestnut trees.

Poisonous fungus: Hypholoma fasciculare - Hypholoma in tufts

Hypholoma fasciculare = Hypholoma in tufts

These poisonous fungi are very commonly found on wood. 

If their yellow color attracts the eyes of the reckless, the bitterness of these mushrooms should discourage the more reckless.

We make available for free download the following file created by Eric MICHON 

and identifying nearly 830 deadly, toxic or unwanted fungi.

Here are some illustrative examples that Eric MICHON has developed:

► The fly agaric (Amanita muscaria) was used by shamans in Siberia for its drunkenness-like symptoms. 

It was forgetting that the intoxication is serious (vomiting, pain, heart rhythm disturbances, hypotension), potentially fatal!

► Phalloid amanita (Amanita phalloids) contains 7 different groups of poisons and toxins! 

The lethal dose is between 25g and 35g of flesh for a 75 kg person, which is very little. 

While slugs and rabbits are not afraid of this fungus, humans and pets are not. 

The first symptoms appear within 6 to 24 hours after consumption (10-12 hours on average): vomiting, severe dehydration, hypovolemia (lack of blood in the circulatory system), RFID, shock, early death or remission, then hepatitis, hepatomegaly , jaundice, cytolysis, hepatocellular failure, gastrointestinal bleeding, hepatic encephalopathy, hypoglycemia, coagulopathy, AKI, and late death. 

Phalloid amanitis is the cause of 90% of deaths recorded in France following the ingestion of a fungus. 

It is therefore the very first mushroom to learn to recognize when you are new to mushroom picking. 

Its main characteristics are (described in terms of everyday language, with all due respect to mycologists): a green hat, but sometimes yellowish or white, dressed in white blades underneath and a rather loose smooth skirt, with the tip of the foot in a white bag, sometimes buried.

► The blue foot “Lepista nuda”, edible in demand for its tender and fragrant flesh, has caused digestive syndromes reported in the event of excessive consumption and especially of mushrooms that are too advanced: it is advisable to pick only the young specimens (purple, firm, curled margin) and of avoid aged, frozen or imbued (waterlogged) specimens.

► The nebulous Clitocybe (Lepista nebularis), consumed under the vernacular name of “Gris de Sapins” or “Petit-gris” in the Franche-Comté region, sometimes even served in certain restaurants in the Jura, randomly caused strong discomfort. 

20 min to 3 hours after the meal, some people have developed digestive problems (nausea, vomiting, diarrhea and abdominal pain). 

It has been noticed that, on isolated poisonings (1 person among the guests), the symptoms are later but also more severe. 

The hypothesis of 2 intoxication mechanisms is plausible but to date no toxin has been identified.

► The returned Clitocybe (Lepita reversed) made people very inconvenienced, likewise for Lepista saeva et lepista irina

The Lepista genus is more than twenty varieties identified in our mountain ranges in eastern France, the most common of which are: Lepista nebularis, nudasordida, flaccida var inversa, glaucocana, saeva, irina et panaeolus.

All these mushrooms have a fairly strong taste even after drying.

► White clitocybes (Sudorien-type poisoning) are too often confused with Mousserons or with Meunier (Clitopilus prunulus).

► The Clitocybe on foot in a club (Ampulloclitocybe clavipes) has an anti-abuse effect which is characterized by different symptoms: flushing, flushing, vasodilation, headache (pulsatile), nausea, vomiting, tachycardia, dyspnea, hyper-sweating, vertigo, dizziness, blurred vision, malaise, faintness, change in blood pressure 'electrocardiogram, chest pain, confusion and ataxia, like the ink-black Coprin; they both went into toxics.

► Although very rare, Clitocybe amoenolens, responsible for acromelalgia (access to intense pain localized in the fingers and toes, such as tingling or burning), can be confused with Lepista flaccida var. reversed.

► “To reject”: this is the statement that was displayed for Hapalopilus rutilans. To be classified as “toxic” from now on because poisoning in France in the hinterland of Nice confirmed the experience of a German couple 20 years ago. 

Confusion with hepatic fistula, took a family from Nice to hospital who presented symptoms observed between 6 and 12 hours after ingestion: abdominal pain, dizziness, hallucinations, visual disturbances and diplopia, general weakness and anorexia, emission of purple urine, renal and hepatic impairment.

► Scleroderma citrina, sometimes used fraudulently to adulterate the truffle, caused gastric poisoning by voluntary ingestions, as well as Megacollybia platyphylla consumed in large quantities. 

For the same reasons, Hygrophoropsis aurantiaca would be involved. 

The “casseroleur” (term by which the mycologists designate, a little pejoratively it must be said, the followers of the mushrooms in the kitchen) does not know parsimony, and yet the mycologists advocate for years a reasoned consumption!

► Consuming too much of the Ear of Judas (auricularia judae) caused skin hemorrhages, which makes it Szechwan Syndrome.

► In 1995 in Monferrat in Isère, the Dauphiné-Libéré, a local newspaper, headlined "a 73-year-old man poisoned by death trumpets": 2 days of questioning before learning that the unfortunate, admittedly toothless, had only eaten this for 6 days. Verdict: intestinal obstruction.

► The cooking of the species is suspect in poisoning with Morels and in the pale Bolete (Boletus luridus). 

Morels are toxic raw because they contain hemolysins which destroy the red blood cells: they are thermolabile toxins, that is to say destroyed by heat, which is why the morels therefore do not become edible, only 'when cooked through, for at least 15 minutes. 

The drying of morels, due to exposure to heat (see our blog post on drying mushrooms), destroys this toxin. 

It is therefore not necessary to cook previously dried morels for so long. 

You should also avoid consuming alcohol while eating morels. 

Additionally, some people may develop an allergy or food sensitivity to morels. 

If you have never eaten morels, it is advisable to eat a small portion the first few times. 

If symptoms appear, stop eating morels.

► Also watch out for the false morel or gyromiter (Gyromitra esculenta) which causes digestive pain, convulsions, fever, liver damage, kidney problems, hemolysis, coma.

► The canary, also called bidaou in the Basque country (Equestre tricholoma) caused several deaths in France in 2000 and 2001. 

The intoxicated, who presented an acute rhabdomyolysis (destruction of the muscle cells) would have made an excessive consumption of it. 

The same applies to tricholoma auratum : these two species have been banned from sale since 2005.

► Several deaths in Japan have been due to the ingestion of Pleurocybella porrigens. Most of the addicts were renal failure with symptoms suggestive of metabolic encephalopathy (disturbance in walking and consciousness).

► Schizophyllum commune, very common in our regions on cut trunks or dead trees, has caused in India, in certain immune-deficient people, serious so-called invasive infections: infection in a patient with bronchopulmonary allergies, but also cases of brain abscesses in people susceptible to sinusitis. 

Cases of maxillary sinusitis with nasal obstruction have been caused by this species: only surgical dissection is effective in this case.  

► In recent years, allergy symptoms (cutaneous, respiratory or digestive) have appeared after ingestion of edible species: button mushrooms (Agaricus bisporus), oyster mushrooms (oyster mushroom) and Bordeaux porcini mushrooms (Boletus edulis). 

Respiratory problems have also been reported with Coprinus comatus, Agaricus campestris et Lycoperdon perlatum

► The Shii-také (lentinus edodes) caused skin allergies with sometimes itchy welts.

► In the case of cardiac weakness for example, it will be advisable to have the light fork with certain edibles such as amanita rubescens et Armillaria mellea. 

These honey-colored armillaries are also reviving mushrooms that pass for fresh mushrooms, while the blades have become stained red, confirming advanced age.

► Gastroenteritis has been observed after ingestion of Cudonia circinans et Spathularia flavida

► The coiled Paxilla (Tapinella involuta) is responsible for Paxillus syndrome. 

The vicious nature of this syndrome comes from the fact that there are inert strains and immunogenic strains. 

If one is unlucky enough to consume immunogenic paxillae a sufficient number of times (x meals), the stock of antibodies accumulated in the body can trigger at meal x + 1, massive hemolysis and various disturbances that can lead to death.

► Several cortinarians of the group Orellanus are fungi whose toxins attack the kidneys. Symptoms are very late, usually several days after a meal! 

A single confusion of annatto-colored cortinarians with chanterelles is sufficient to be dialyzed with lifelong treatment.

► Leprocybes are unfortunately still too often picked up because people appreciate their beautiful color and the beautiful appearance of these species!

► Until recently, in sweet russulas, Russula olivacea caused poisoning in the Spanish Basque country. 

Local mycologists have recorded over the last two decades, more than 40 cases of poisoning with this fungus with rather late gastrointestinal symptoms (6-8 hours): the russulas were eaten undercooked and in particular prepared on the barbecue. . 

A mycologist from French-speaking Switzerland witnessed significant vomiting, relatively late (about 4 hours) caused by the consumption of this probably undercooked russula either.

Reminder of the rules to be observed:

 

In a press release, the Directorate General of Health (DGS) and the National Institute for Sanitary Watch (INVS) recall the precautions to be observed in the face of toxic fungi, which can very much resemble edible species.

"Only collect mushrooms that you know perfectly" and "if there is the slightest doubt", you must have your harvest checked by a specialist, first of all a pharmacist. "

► "Pick only specimens in good condition", "do not pick near polluted sites" and "separate harvested mushrooms by species", as one poisonous fungus can infect others. "

► Tremor, dizziness, visual disturbances, nausea and vomiting: symptoms of poisoning may appear up to twelve hours after consumption.

► In an emergency, call a poison control center immediately (www.centres-antipoison.net) or the center 15.

And our additional tips in conclusion: before preparing your wild mushrooms for consumption, ask yourself again whether you are sure of their edibility. 

Did you consult a specialist (mycologist or expert pharmacist)? What if you were wrong anyway? If in doubt, do not.

And avoid consuming several mushrooms of different species at the same time in the same dish. 

Even if you are sure of yourself, keep at least one fresh copy and a photo of your entire harvest: this valuable information may be able to help poison control centers take care of you more quickly.

Read the article on a toxic fungus causing Charcot's disease.

Discover the article dedicated to deaths from fungal infections (which) have doubled in ten years – The Conversation – January 2024

Consult the July 2022 ANSES toxicovigilance study report: "Seasonal monitoring of accidental mushroom poisonings - Report on cases recorded by poison control centers (from July to December 2021) ».

In terms of guides for determining fungi, here are our recommendations:

The essential mushroom picker guide (Belin - € 15): pocket-sized, with a plastic cover (which is very practical in the field).

Mushrooms in nature (Delachaux and Niestlé - 29 € 40): all the mushrooms from our regions, photographed from all angles.

 

And finally here is the reference bible of eminent French mycologists:

The guide to mushrooms in France and Europe (Guillaume EYSSARTIER and Pierre ROUX - Belin - € 36).

Cover photo credit of the “Fly Agaric” article cover: Michel RICHARD – Haut-Rhin Mycological Society

Photo The Mushroom Shop

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