A spore-forming soil bacterium of grazing animals that causes anthrax in people who handle infected animals or their products. Explore its illustrative 3D model, human context, and sources.
PHAC describes B. anthracis as Gram-positive, rod-shaped cells of 1.0 to 1.5 by 3 to 8 micrometres that occur singly or in chains, non-motile, facultatively anaerobic, and forming metabolically dormant, environmentally resistant endospores; some strains produce capsules and exotoxins. PHAC states that at least 2,000 cases of human anthrax occur annually worldwide and that approximately 95% result from handling or processing infected meat or animal products, with human-to-human transmission rare. CDC states that people usually get sick if they come in contact with anthrax spores in infected animals or contaminated animal products, through a cut or scrape in the skin, by breathing them in, or by eating contaminated food or water. The cutaneous form accounts for about 95% of cases and has mortality under 1% with treatment; inhalational anthrax is far more dangerous.
The route of exposure changes the outcome more than almost any other organism in this catalogue. PHAC gives mortality under 1% for treated cutaneous anthrax, which accounts for about 95% of cases, 4 to 50% for the gastrointestinal form, and 45% for inhalational anthrax even with early treatment, rising to 97% once the illness progresses. Human-to-human transmission is rare, so risk follows animal and animal-product exposure rather than contact with other people.
Bacillus anthracis · Two broad vegetative rods suggest a representative chain. No capsule or endospore is assigned to this view. 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: Bacillus anthracis · pathogen safety data sheet.
Source check: 2026-09-20. Educational content; independent scientific review remains pending.