Rocky Mountain spotted fever in Panama: a cluster description.

Rocky Mountain spotted fever (RMSF) is a tick-borne infection caused by Rickettsia rickettsii. We report a cluster of fatal cases of RMSF in 2007 in Panama, involving a pregnant woman and two children from the same family.  The woman presented with a fever followed by respiratory distress, maculopapular rash, and an eschar at the site from which a tick had been removed.  She died four days after disease onset.  This is the second published report of an eschar in a patient confirmed by PCR to be infected with R. rickettsii.  One month later, the children presented within days of one another with fever and rash and died three and four days after disease onset. The diagnosis was confirmed by immunohistochemistry, PCR and sequencing of the genes of R. rickettsii in tissues obtained at autopsy.