MYCOTIC POISONIONG

Ingestion of poisonous fungi or its toxins can cause two types of clinical conditions.

A. Mycetismus: It is the toxicosis resulting from the ingestion of poisonous mushrooms. Following are the examples.
1. Mycetismus gastrointestinalis: Nausea, vomiting and diarrhea. It is due to ingestion of mushroom Russula emetica.
2. Mycetismus nervosus: Involves GIT and parasympathetic nervous system. This is due to ingestion of Amanita muscaria.
3. Mycetismus choleriformis: Severe GIT symptoms seen. This is due to ingestion of Amanita phalloides.
4. Mycetismus cerebralis: Transient hallucination seem. This is due to ingestion of Psilocybe sps.

Amanita phalloides poisoning: Amanita phalloides poisoning is mediated by a number of toxins, the most important of which
are the amatoxins. These toxins interfere with DNA transcription by inhibiting RNA polymeraseB. Synthesis of messenger RNA and subsequent protein synthesis is interrupted. Cells with high rates of protein synthesis (e.g. those of the gastrointestinal tract, the liver and the kidneys) are particularly sensitive to injury. Severe poisoning can occur with 5-7 mg amatoxin, an amount that can be present in a single mushroom weighing about 50 g. Amatoxins are heat stable and resist freezing temperatures down to -25°C. The lethal dose of amatoxins is approximately 0.1 mg/kg body weight.

B. Mycotoxicosis: This condition results from ingestion of toxins of fungal origin in food. Examples are
1. Aflatoxin: Produced by Aspergillus flavus. They are associated with heopatocellular carcinoma and colonic carcinoma. Mostly related to consumption of maize, groundnut etc.
2. Ergotamine: Produced by Claviceps purpura. Causes gangrenous lesions and is associated with consumption of rye seed.
3. Ochratoxin: Produced by Aspergillus ochraceous. Cause renal necrosis, hepatic degeneration and enteritis. Associated with corn, wheat, barley and rye.
4. Rubratoxin: Produced by Penicillium rubrum. Causes congestion and hemorrhage in liver and kidney.
5. Trichlorothecene: Produced by Fusarium sps, Stachybotrys: Most are potent inhibitors of eukaryotic protein synthesis and of mitochondrial respiration. Causes nausea, vomiting, diarrhea, fever, vertigo, convulsions, skin irritation, and internal bleeding. Naturally-occurring cases presents as Alimentary Toxic Aleukia, a lethal condition related to the consumption of moldy grains. It is a potential biological warfare agent.
6. Zearalenone: Produced by Fusarium graminarum. It has effect on reproductive system.