Abstract: The authors detected Rickettsia genus organisms using shell vial and polymerase chain reaction (PCR)/sequencing analysis in blood clots in patients suspected of having Brazilian spotted fever (BSF). DNA was detected using PCR with three sets of primers to access the gltA, ompA, and ompB genes. Sequence analysis was carried out using an automatic sequencer with Bioedit® software. Seventy-five percent of the culture samples were positive and all samples amplified rickettsial gene fragments. To date, 46% of the samples have been sequenced.