There are three main, naturally occurring, epidemiological types of botulism: food-borne, intestinal colonization (infant botulism) and wound botulism. The neurological signs and symptoms are the same for all three epidemiological types and may include respiratory paralysis.

Wound botulism is caused by growth of cells and release of toxin in vivo, is associated with traumatic wounds and abscesses and has been reported in drug users, such as those injecting heroin or sniffing cocaine. Up to the end of 1999 there were no confirmed cases of wound botulism in the UK. Between the beginning of 2000 and the end of December 2002, there were 33 clinically diagnosed cases of wound botulism in the UK and Ireland. All cases had injected heroin into muscle or by 'skin popping'. The clinical diagnosis was confirmed by laboratory tests in 20 of these cases. Eighteen cases were caused by type A toxin and two by type B toxin.