Read condition-specific symptoms and clinical context for Clostridium botulinum. A spore-forming bacterium whose toxin causes botulism — rare, preventable and a medical emergency when it happens.
PHAC describes C. botulinum as Gram-positive, anaerobic, rod-shaped, spore-forming bacilli ranging from 0.5 to 2.4 micrometres in diameter and 1.6 to 22.0 micrometres in length, producing oval-shaped, metabolically dormant endospores that are highly resistant to environmental stressors. Seven toxin serotypes A to G exist and PHAC records that serotypes A, B, E and rarely F cause human botulism; WHO describes the same four types. CDC describes botulism as a rare but serious illness caused by a toxin that attacks the body’s nerves, causing difficulty breathing, muscle paralysis and even death. PHAC states that human-to-human transmission of C. botulinum does not occur.
WHO describes foodborne botulism as caused by ingesting preformed toxin, with symptoms usually appearing within 12 to 36 hours after exposure, within a range of 4 hours to 8 days. PHAC gives an incubation period of 12 to 72 hours.
Possible symptoms: Marked fatigue, weakness and vertigo; Blurred or double vision; Dry mouth; Difficulty swallowing; Difficulty speaking or altered voice; Descending muscle paralysis.
CDC states that all kinds of botulism can be fatal and are medical emergencies, and advises seeking immediate medical attention if symptoms appear. WHO gives a case-fatality of 5 to 10% when proper treatment is not provided promptly.
CDC describes infant botulism as affecting infants when spores enter the intestines, grow and produce toxin. PHAC gives an incubation period of 18 to 36 hours and a fatality rate of less than 1% with supportive care.
Possible symptoms: Constipation; Weakness and poor feeding; Muscle paralysis.
PHAC gives a fatality rate of less than 1% with supportive care. Infant botulism is diagnosed and managed clinically; this app gives no feeding or treatment advice.
CDC describes wound botulism as developing when spores enter wounds, with people who inject illicit drugs at greater risk. PHAC gives an incubation period of 7 to 21 days and a fatality rate of 5 to 10%, with symptoms similar to the foodborne type but without gastrointestinal signs.
Possible symptoms: Blurred or double vision; Difficulty swallowing; Difficulty speaking; Descending muscle paralysis.
PHAC gives a 5 to 10% fatality rate for wound botulism and a longer incubation period of 7 to 21 days than the foodborne form. Suspected botulism is an emergency.
Spores in soil or food are not the same as botulism.
WHO and CDC describe illness arising either from toxin already formed in food or from spores that germinate and produce toxin in an intestine or wound, so the presence of spores alone does not mean illness. The bundled sources give no symptom list for this state, and none is invented here. PHAC states that human-to-human transmission of C. botulinum does not occur, so someone with botulism is not infectious to others. This profile assigns no normal human carriage state.
Food-preservation questions and clinical questions are separate. Safe canning and preservation guidance comes from food-safety authorities; symptoms are assessed clinically and urgently.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.