CD40LG and scrub typhus: On the other hand, the PCR by CSF test displays the lowest cumulative positivity rate, with a more gradual increase that peaks around 0.10 by the seventh or eighth day and then remains steady. This comparison highlights the varying effectiveness of each test, with ELISA for scrub typhus IgM emerging as the most responsive across the duration of the illness, followed by PCR by PBMC and PCR by CSF (Figure 3).