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 hose mouse mite. In overcrowded squalid apartment building infested with mice harboring R. akari as parasite.

A cluster of cases in New Your 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 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 Balkan States, Korea, Ukraine, South Africa and major US cities. The average incidence of rickettsiapox is about 30 /year in the USA.

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