This is about the disease Typhus. See Typhus (monster) for the monster in Greek mythology, or typhoid fever for a totally different disease that because of its similar name is often confused with it.

Typhus is a name given to several similar diseases caused by Rickettsiae bacteria. It comes from the Greek typhos, meaning smoky or hazy, describing the state of mind of those affected with typhus. Symptoms common to all forms of typhus are a fever which may reach 39°C (102°F) and a headache. In tropical countries, typhus is often mistaken for dengue.

There are three types of typhus:

• Epidemic typhus (also called "louse-bourne typhus") often causes epidemics following wars and natural disasters. The causative organism is Rickettsia prowazekii, transmitted by the human body louse (Pediculus humanus corporis). Symptoms are headache, fever, chills, exhaustion, and rash. This form of typhus is also known as "prison fever" and as "ship fever", because it becomes prevalent in crowded conditions in prisons and aboard ships.
• Endemic typhus (also called "flea-borne typhus" and "murine typhus") is caused by Rickettsia typhi , transmitted by fleas infesting rats, and, less often, Rickettsia felis , transmitted by fleas carried by cats or possums. Symptoms include headache, fever, chills, joint pain, nausea, vomiting, and cough.
• Scrub typhus (also called "chigger-borne typhus") is caused by Orientia tsutsugamushi and transmitted by chiggers, which are found in areas of heavy scrub vegetation. Symptoms include fever, headache, muscle pain, cough, and gastrointestinal symptoms.

Definitive diagnosis can be obtained by serological testing. Treatment is often with tetracycline or related antibiotics.

There are a number of other diseases caused by Rickettsiae, including Rocky Mountain spotted fever (also known as "Tick typhus"), Rickettsialpox and Boutonneuse fever.

Typhoid fever is a completely different disease caused by various strains of Salmonella, and should not be confused with typhus despite their similar-sounding names.

References

Nature 396, 109 - 110 (12 November 1998) by Michael W. Gray