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Mushroom Poisoning among Laotian Refugees -- 1981

In the period, December 1-3, 1981, 7 Laotian refugees were seen at a Sonoma County California hospital for apparent mushroom poisoning; 6 had nausea, vomiting, diarrhea, dehydration, and elevated liver enzymes. All persons had eaten mushrooms that were gathered and eaten on November 30, although 1 week earlier 20-30 Laotians had eaten mushrooms gathered in the same area without incident. The incubation period was variable, but most patients experienced gastrointestinal distress within 8 hours. Three persons were treated in the intensive care unit, but all recovered and were discharged within 7 days.

Several remaining cooked mushrooms were examined at Sonoma State University; all but 1 were identified as Russula species. The remaining specimen could not be identified, probably because of cooking. The mushrooms examined may not have been representative of those actually consumed.

Laotians customarily gather wild mushrooms in their homeland and attempt to identify poisonous species by boiling the mushrooms with rice; if the rice turns red, the mushrooms are deemed poisonous. Because the Sonoma County mushrooms did not cause a color reaction, it was assumed they were safe to eat. Reported by K Rattanvilay, N Tavares, G Eliaser, MD, G Hands, MD, S Boynton, Community Hospital, Santa Rosa; J Young, PHN, R Holtzer, MD, Sonoma County Health Dept, TG Tong, PharmD, San Francisco Poison Control Center, RR Roberto, MD, SB Werner, MD, Infectious Disease Section, California Dept of Health Svcs; Enteric Bacteriology and Epidemiology Branch, CDC.

Editorial Note

Editorial Note: Mushroom poisoning can be produced by about 100 of the 2,000 species known. In the United States, mushrooms of the genera Amanita and Galerina produce amanitins and phallotoxins, which are common causes of mushroom poisoning. The most feared fungi are those that produce amanitin, which include the "deathcap" Amanita phalloides. A. phalloides has become increasingly common in the San Francisco bay region in recent years. The odor of fresh A. phalloides is similar to raw potatoes. Symptoms generally begin 6-24 hours after ingestion and may include the explosive onset of violent abdominal pain, vomiting, diarrhea, hematuria, fever, tachycardia, hypotension, rapid volume depletion, fluid and electrolyte imbalance, and extreme thirst. After a short phase of improvement, hepatic, renal, and central nervous system damage may ensue. The mortality rate is 50%, and those who recover do so slowly. Treatment is supportive, and thioctic acid, charcoal hemoperfusion, and vitamin C may be useful (1,2).

Other genera of mushrooms, including the Russula genus implicated in the California outbreak, produce less lethal toxins. The Russula toxin has not been identified, but it results in a shorter incubation period--1-2 hours--followed by minor gastrointestinal and parasympathetic symptoms and hallucinations (1). Russula emetica can produce additional toxins, including muscarine.

Most cases of mushroom poisoning occur in late summer and early fall. Early abundant rains and mild temperatures in northern California have produced a profusion of mushrooms, some of which are poisonous. Nontoxic mushrooms may grow in the same area with toxic ones, and even trained mycologists may confuse toxic varieties with edible ones because of the extensive variations among species. There are no simple tests to identify poisonous mushrooms and no safe ways to detoxify the poisonous varieties.

Identification of implicated mushrooms may be difficult if specimens have been prepared and cooked. Since a variety of mushrooms may have been ingested in most poisoning situations, reliance cannot be placed on the initial symptoms. Gastric contents, stool, and mushroom samples may be assayed for toxins by radioimmunoassay (3).

The San Francisco Poison Control Center recommends routine administration of ipecac after ingestion of any wild mushrooms of questionable identification. The Infectious Disease Section offers its assistance in suspected mushroom poisoning, and information is available from local mycological societies, colleges, and poison control centers.

In the last 5 years, 16 outbreaks involving 44 cases of mushroom poisoning were reported to CDC; 23 cases were from California. In 1981 in California, 1 death in Santa Cruz County and 2 in Marin County were attributed to mushroom poisoning.


  1. Becker CE, Tong TE, Boerner U, Roe RL, Scott RAT, MacQuarrie MB. Diagnosis and treatment of Amanita phalloides-type mushroom poisoning. West J Med 1976;125:100-9.

  2. Wauters JP, Rossel C, Farquet JJ. Amanita phalloides poisoning treated by early charcoal haemoperfusion. Brit Med J 1978;2:1465.

  3. Mushroom poisoning. Lancet 1980;2:351-2.

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