Murine typhus, or endemic typhus, is one of the oldest recognized, most common, but least reported arthropod-transmitted zoonoses. Endemic typhus is an infection by a rickettsial organism (sometimes called a viral infection or a bacterial infection) spread by fleas that live on mice and rats. The faeces of infectious fleas contaminate a bite or skin abrasion, usually when the victim scratches or rubs a bite. The disease can also be caused by inhalation of dried faeces. Symptoms of fever, headache, muscle pain and rash occur gradually one to two weeks after contact, and they last for one to two weeks if untreated. The disease typically is mild with rapid recovery; fatalities are rare, but if untreated average 1-2 percent.
The causative organism Rickettsia muricola (or R. typhi, formerly called R. mooseri) is closely related to R. prowazeki which causes epidemic typhus. It is usually transmitted to man by the rat-flea Xenopsyalla cheopis. Rats and mice are the natural hosts and the main source of infection; the human flea (or louse) acts as the transmitter from person to person.
This form of typhus fever is world-wide in distribution and found wherever individuals are crowded together in unsanitary, rat-infested areas (hence its old names of jail-fever and ship typhus). Mortality is very low.
The classic reservoir and vector are the rat and rat flea, respectively; however, the role of cat fleas and opossums in maintaining this microorganism has been suggested in some areas of the United States where rats and rat fleas are absent. Although murine typhus has a worldwide distribution, it is often unrecognized, and documented cases are rarely reported, particularly in tropical countries. Recent cases of murine typhus in in patients returning to Europe from Indonesia indicate that murine typhus should be considered a possible cause of imported fever from Indonesia.