Rickettsiapox

 

                                                           Rickettsiapox

                                                        PKGhatak, MD

Rickettsiapox is a milder form of systemic disease, the predominant lesion is the skin infection produced by Rickettsia akari. This bacterium is a parasite of the house mouse mite. In an overcrowded squalid apartment building infested with mice harboring R. akari as a parasite.

A cluster of cases in New York City in 1946 led to the discovery of the mite and bacterium by an amateur entomologist, Charles Pomerantz. Earlier, investigators considered rickettsiapox as modified chicken pox.

The mite bite produces a red papule, which turns into a vesicle and heals, leaving a black eschar. A week later, the patient develops a sudden onset of chills, fever, headaches, diffuse body aches and pain and photophobia. After 2 to 4 days, the entire body is covered with red maculopapular eruptions, soon they turn into vesicles. The skin lesions heal in 10 days and the scabs are shed.

Skin biopsy when treated with conjugated antirickettsia globulin can detect rickettsia antigen. PCR tests are also developed. The 4-fold rise in antibody titer is a standard initial diagnostic test. Antibiotic Doxycycline is given for 7 days.

The disease is milder in comparison with other forms of rickettsiosis and is usually self-limited.

Rickettsiapox is endemic in the Balkan States, Korea, Ukraine, South Africa, and major US cities. The average incidence of rickettsial is about 30 /year in the USA.

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