biostudies-literatureUnknown20(2)Phuklia W<h4>Background</h4>Murine typhus is a flea-borne disease caused by Rickettsia typhi that typically presents as an acute febrile illness. The diagnosis is often missed, leading to delays in appropriate treatment. A qPCR targeting a single gene (ompB) for R. typhi is widely used for diagnosis; however, it has low sensitivity for detecting bacterial DNA in patients' blood. We aimed to increase sensitivity of detection of R. typhi using qPCR by targeting a gene containing repetitive sequences, sca2 (surface cell antigen 2).<h4>Methodology</h4>We compared diagnostic accuracy with the standard assay targeting single sequence ompB (outer membrane protein B). Specificity, sensitivity, and bacterial load measurement of both assays were compared using stored EDTA-anticoagulated buffy coat samples frPLoS neglected tropical diseasese0014004https://www.ebi.ac.uk/biostudies/studies/S-EPMC12919770biostudies-literatureTargeting surface cell antigen 2 increases sensitivity of Rickettsia typhi detection.PMC12919770Phuklia WMayxay MAshley EAVongphachanh SPadith KPhommasone KChansamouth VNewton PNRobinson MTfalseTargeting surface cell antigen 2 increases sensitivity of Rickettsia typhi detection.<h4>Background</h4>Murine typhus is a flea-borne disease caused by Rickettsia typhi that typically presents as an acute febrile illness. The diagnosis is often missed, leading to delays in appropriate treatment. A qPCR targeting a single gene (ompB) for R. typhi is widely used for diagnosis; however, it has low sensitivity for detecting bacterial DNA in patients' blood. We aimed to increase sensitivity of detection of R. typhi using qPCR by targeting a gene containing repetitive sequences, sca2 (surface cell antigen 2).<h4>Methodology</h4>We compared diagnostic accuracy with the standard assay targeting single sequence ompB (outer membrane protein B). Specificity, sensitivity, and bacterial load measurement of both assays were compared using stored EDTA-anticoagulated buffy coat samples fr2026-01-01T00:00:00Z2026 Feb2026-07-16T10:06:00.488Z2026-07-09T10:48:53.016ZS-EPMC129197704171262210.1371/journal.pntd.0014004