Several distinct rickettsiae cause typhus fevers in humans. Each agent produces disease with a distinct epidemiology, but all cause illness with fever, headache, and rash.
Epidemic typhus is passed from human to human by the body louse.
Endemic, or murine, typhus occurs worldwide and is transmitted by rat fleas. Tickborne typhus fevers occur most commonly in parts of Africa and Asia. Scrub typhus, transmitted by rodent mites, occurs in Asia and the South Pacific. Occurrence The highest incidence of endemic typhus in temperate areas occurs during the summer months when rats and their fleas are most active and abundant. Epidemic typhus is rare except during periods when municipal services are disrupted, as in war or natural disaster.