A spore-forming bacterium whose toxin causes botulism — rare, preventable and a medical emergency when it happens. Explore its illustrative 3D model, human context, and sources.
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.
The illness comes from a neurotoxin, not from bacteria spreading through the body or between people. WHO states the disease can be fatal in 5 to 10% of cases when proper treatment is not provided promptly, and PHAC gives modern foodborne fatality of less than 5%, infant botulism less than 1% with supportive care, and wound botulism 5 to 10%. CDC emphasises that all kinds of botulism can be fatal and are medical emergencies.
Clostridium botulinum · One sporulating rod with a subterminal oval endospore and local swelling. A dividing vegetative cell is a separate state in the replication diagram. This is a species-informed teaching diagram; colours, proportions, envelope spacing and internal detail are illustrative. The model uses muted illustrative colours; stains, colony pigments and microscopy colourization are not natural cell colours. Anatomy is enlarged for phone viewing. Morphology reference: Clostridium botulinum · pathogen safety data sheet.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.