(See also Overview of Rickettsial and Related Infections.)
Rickettsialpox, a rickettsial disease, occurs in many areas of the US and in Russia, Korea, and Africa. The vector, a small, colorless mite, is widely distributed. It infects the house mouse and some species of wild mice. Humans may be infected by chigger (mite larvae) or adult mite bites.
An eschar appears about 1 week before onset of fever as a small papule 1 to 1.5 cm in diameter, then develops into a small ulcer with a dark crust that leaves a scar when it heals. Regional lymphadenopathy is present. An intermittent fever lasts about 1 week, with chills, profuse sweating, headache, photophobia, and muscle pains. Early in the febrile course, a generalized maculopapular rash with intraepidermal vesicles appears, sparing the palms and soles.
The disease is mild; no deaths have been reported.
For details of diagnosis, see Diagnosis of Rickettsial and Related Infections.
Treatment is doxycycline 100 mg orally twice a day for 5 days or ciprofloxacin 750 mg orally twice a day for 5 days.
For prophylaxis, mouse harborages must be destroyed, and the vector controlled by residual insecticides.