There are a number of rickettsial infections. Rickettsialpox is a relatively mild disease caused by a member of the bacterial family called Rickettsia. Rickettsialpox causes rash, fever, chills, heavy sweating, headache, eye pain (especially when exposed to light), weakness, and achy muscles. Rocky Mountain spotted fever (RMSF), a tick-borne illness, Q fever, and Trench fever are also caused by bacteria and result in high fevers and characteristic rashes.

Like other members of the family of Rickettsia, the bacteria causing rickettsialpox live in mice. Tiny mites feed on these infected mice, thus acquiring the organism. When these mites feed on humans, the bacteria can be transmitted.

Rickettsialpox occurs mostly within cities. In the United States, the disease has cropped up in such places as New York City, Boston, Philadelphia, Pittsburgh, and Cleveland. It has also been identified in Russia, Korea, and Africa.

The bacteria causing RMSF is...