Paper I
Question
Mycotoxins of medical importance
Answer
Mycotoxins of medical importance: toxic secondary metabolites produced by certain fungi/moulds, capable of causing disease (mycotoxicosis) in humans and animals, typically through contaminated food (mycotoxicosis is a toxin-mediated illness, distinct from an active fungal infection/mycosis).
- Aflatoxins — produced by Aspergillus flavus and Aspergillus parasiticus, contaminating improperly stored groundnuts, cereals, and other crops; hepatotoxic and strongly hepatocarcinogenic (a major risk factor for hepatocellular carcinoma, particularly in the presence of chronic Hepatitis B infection).
- Ochratoxin A — produced by Aspergillus and Penicillium species; nephrotoxic, associated with a form of chronic interstitial nephropathy.
- Ergot alkaloids — produced by Claviceps purpurea (a fungus infecting rye and other cereals); causes ergotism, characterized by vasoconstriction (gangrenous form) and/or neurological/convulsive symptoms (convulsive form).
- Trichothecenes (e.g., T-2 toxin) — produced by Fusarium species; cause gastrointestinal, haematological (bone marrow suppression), and dermatological toxicity.
- Fumonisins — produced by Fusarium species, contaminating maize; associated with oesophageal cancer risk and neural tube defects in some epidemiological studies.
Clinical relevance: mycotoxin exposure occurs mainly via ingestion of contaminated food (particularly improperly stored grains/nuts in humid conditions), making food storage/hygiene practices important preventive measures; aflatoxin, given its hepatocarcinogenic potential, is of particular public-health importance in endemic regions.