A set of algorithms for diagnosing ST, Scrub Typhus Improved Criteria (STIC) has suggested the use of isolation of O. tsutsugamushi, admission of IFA IgM titer >1:12,800, or 4-fold titer increase in IFA IgM in paired sera or positive PCR results [17] targeting two of the three genes (56 kDa, 47 kDa or groEL). This evidence concerns the gene CD40LG and typhus.