Epidemic typhus fever is an acute rickettsial disease transmitted among victims by the human body louse, Pediculus humanus corporis. Its characteristic symptoms include high fever, prostration, headache and body aches, and a widespread rash that covers the trunk and limbs of the body. Mortality rates in untreated cases vary widely. Broad-spectrum antibiotics provide an effective therapy for the disease.

Because of its association with conditions of human misery, typhus has been known by many names. Jail distemper and its variations – morbus carcerum, gaol fever, and jayl fever – indicate the prevalence of typhus in detention facilities. Ship fever, camp fever, and famine fever reflect the poor hygiene characteristic of travel, of military expeditions, and of refugee populations. The characteristic rash of typhus has elicited other descriptive names, including spotted fever in English, Fleckfieber and typhus exanthematicus in German, typhus exanthématique in French, tifo exantemático and tabardillo in Spanish (the latter meaning “red cloak”), and typhus-esantematico in Italian. Although Hippocrates applied the word typhus, from the Greek word meaning smoky or hazy, to confused or stuporous states of mind frequently associated with high fevers, the word was not associated with the disease as it is currently known until the eighteenth century. After murine typhus was identified, the appellation typhus historique was sometimes applied to the classic, epidemic disease.

Etiology and Epidemiology

Occurring as a natural infection only in humans, epidemic typhus is caused by Rickettsia prowazekii. It is spread from host to host by the human body louse, P. humanus corporis, and less often by the human head louse, Pediculus humanus capitis.