Typhus, epidemic: A severe acute disease with prolonged high fever up to 40° C (104° F), intractable headache, and a pink-to-purple raised rash, due to infection with a microorganism called Rickettsia prowazekii.
Among the other signs and symptoms of the disease are cough, dyspnea (difficulty breathing), vomiting, splenomegaly (enlargement of the spleen), hypotension (low blood pressure), and neurologic abnormalities including seizures, coma, and mental confusion.
R. prowazekii is found worldwide. It is transmitted by the human body louse (Pediculus humanus corporis). The lice become infected on typhus patients and transmit the illness to other people.
The mortality rate from epidemic typhus increases with age. Over half of untreated persons age 50 or more die but people of all ages can perish of the disease. Anne Frank died of epidemic typhus in the Bergen-Belsen concentration camp.
The neurologic features gave the disease its name from the Greek word "typhos," which means smoke, cloud, and stupor arising from fever. Epidemic typhus is also known as classic typhus, European typhus, jail fever, louse-borne typhus, ship fever.