Q.13 Ergotism, which is characterized by gangrene, nervous spasm, burning sensation,
hallucinations and temporary ‘insanity’ is caused by
Answer: (1) Claviceps purpurea
Ergotism causes gangrene from vasoconstriction, nervous spasms and hallucinations from neurotoxic alkaloids, and burning sensations from peripheral ischemia—all hallmarks of Claviceps purpurea infection in rye and cereals.
Option Analysis
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(1) Claviceps purpurea: Correct. This ascomycete fungus produces ergot sclerotia in grain heads, laden with ergot alkaloids (ergotamine, ergometrine) that trigger convulsive ergotism (spasms, hallucinations, “St. Anthony’s Fire”) and gangrenous ergotism.
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(2) Phytophthora: Incorrect. Oomycete causing late blight (potato, tomato); symptoms are foliar necrosis and root rot, no neurotoxic alkaloids or gangrene.
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(3) Pilobolus: Incorrect. Zygomycete that forcibly discharges sporangia for dung dispersal; harmless to humans, causes no poisoning [prior context].
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(4) Rhizopus stolonifer: Incorrect. Bread mold (Zygomycota) causing soft rot and mucormycosis in immunocompromised patients; no association with ergotism alkaloids or systemic poisoning [prior context].
Ergotism Claviceps purpurea gangrene nervous spasm hallucinations is a classic microbiology question in exams like GATE Life Sciences, testing fungal pathogenesis knowledge.
Ergotism Pathophysiology
Claviceps purpurea infects rye ovaries, replacing grains with purple sclerotia rich in ergopeptine alkaloids. Consumption triggers two syndromes: gangrenous (dry gangrene from arteriolar vasoconstriction, burning limb pain) and convulsive (serotonin-like CNS effects causing spasms, mania, hallucinations).
Historical Context
Known as “St. Anthony’s Fire” since Middle Ages, epidemics killed thousands via limb loss or neurotoxicity. Modern outbreaks rare due to grain cleaning, but alkaloids inspire migraine drugs (ergotamine).
Exam Differentiation
Phytophthora (blight), Pilobolus (coprophilous dispersal), Rhizopus (mucormycosis) lack neurovascular toxins. Claviceps uniquely matches all listed symptoms via alkaloid action.
This underscores fungal secondary metabolites’ dual role in disease and pharmacology.
