Rickettsiosis caused by Rickettsia conorii in Uruguay.

The first three human cases of rickettsiosis caused by Rickettsia conorii in Montevideo, Uruguay were described in 1990. All of them showed an initial papulosquamous lesion on the scalp from a canine tick bite (Amblyomma triste). At the same time, fever and regional adenopathies were observed. Serological diagnosis was made by the indirect IgM immunofluorescent technique on glass smears of R. conorii (Biomerieux Laboratories, France). All patients had a benign disease course after been treated with oral tetracyclines. Other authors later developed clinical and serological studies for R. conorii rickettsiosis in a nearby county, confirming our original findings. The tache noir and a light exanthema were also noticed. We have seen several similar cases since that date. Most of them were from rural areas, and two presented with the classical tache noir and a maculopapular rash with severe symptomatology. A. triste, a South American tick with deep anthropophilia, appears as the usual transmitting vector of the disease in the country. A review of the literature reveals a very intriguing absence of similar cases in the Americas including the USA. New studies are necessary to resolve this issue. The possibility that a new species of rickettsia responsible for the disease in Uruguay is also considered.