CD40LG and scrub typhus: Detection of antibodies against O. tsutsugamushi by IFAT is the gold standard in diagnosing scrub typhus.22 IgM seroconversion is usually detectable by the end of the first week after symptom onset, followed by IgG near the end of the second week.23 In our study, the earliest detection of antibodies was in the first week and the median time of seroconversion was week 2.