However many of these criteria have limitations in scrub typhus: serology is complicated by the significant observed antigenic heterogeneity of disease-causing strains; positivity cut-off titers for single admission IgM are unreliable for different areas of endemicity and demonstrate wide ranges; dynamic serology requires a follow-up sample and cannot guide patient management, bacterial isolation while very specific is hampered by low sensitivity and requires even more time. This evidence concerns the gene CD40LG and scrub typhus.