Causative Agent
Bacillus anthracis
- Aerobic, gram-positive, rod-shaped, encapsulated and spore-forming bacterium
Incubation Period
1 - 6 days (up to 30 days)
Infectious Period
Articles and soil contaminated with spores can remain infective for decades.
Transmission
A zoonotic disease mainly of herbivorous animals; transmitted by direct contact with B. anthracis-infected animal tissues or products from infected animals i.e. drums, or with anthrax spores in soil. Humans are generally incidental hosts.
Anthrax in human is not considered contagious; person-to person transmission of cutaneous anthrax has rarely been reported.
Three forms exist:
- Cutaneous anthrax: As a result introduction of the spore through the skin (especially via abrasions).
- Gastrointestinal anthrax: As a result of ingestion of infected tissues.
- Inhalation anthrax: As a result of inhaling spores aerosolized by industrial processing of contaminated materials i.e. hides, among persons working with contaminated animal skin or bioterrorism.
Epidemiology
Most common in agricultural regions in Central and South America, sub-Saharan Africa, Central and Southwestern Asia and Southern and Eastern Europe.
Three main forms of disease:
- Cutaneous: Usually manifests as a black, necrotic skin lesion.
- Gastrointestinal: Rare, but highly fatal form that occurs after ingestion of contaminated meat.
- Inhalational: Most lethal form (mortality > 80%) that occurs following inhalation of spores.