[Rickettsial spotted fever in the Paraná Delta. An emerging disease].

We describe a case of rickettsial spotted fever in the Paraná Delta region of Buenos Aires province in Argentina. The patient developed an acute febrile syndrome characterized by myalgias, headache, asthenia and moderate odynophagia, followed by a diffuse macular, papular, and purpuric exanthema. The patient had been bitten recently by a tick on the left preauricular region and an erosive papular lesion was evident at the bite site. An indirect immunofluorescence antibody assay identified antibodies reactive with spotted fever group rickettsiae in the patient's serum. The patient improved rapidly with doxycycline. Several considerations relating to the identity of the rickettsial species and tick vector are discussed, including the possibility that this patient's illness may have been caused by Rickettsia parkeri.