An illness produced by the exotoxin of Clostridium botulinum and occasionally other clostridia, and characterized by paralysis and other neurological abnormalities. There are seven principal toxin types involved (A–G); only types A, B, E, and F have been implicated in human disease. Types C and D produce illness in birds and mammals. Strains of C. barati and C. butyricum have been found to produce toxins E and F and have been implicated in infant botulism. There is serologic cross-reactivity between C. botulinum and C. sporogenes and C. novyi. Botulinal toxin is among the most potent poisons known; it has a heavy chain (molecular weight about 100,000) and a light chain (about 50,000) joined by a disulfide bond.