DIAGNOSIS OF EMERGING AND REEMERGING SCRUB TYPHUS

Scrub typhus accounts for upto 23% of all acute febrile illness in endemicity in the Asia-Pacific region, and is also newly found in other continents. Despite of reemergence in Asia and emergence in other region, there is no effective human vaccine. And there are few convenient and rapid diagnostic methods, so scrub typhus has appeared as a significant threat to public health. Rapid diagnostic test (RDT) of scrub typhus can be recommended as point-of-care test (POCT) for on-site diagnosis in the area with resource-poor settings such as poor, remote and rural laboratories in which immunofluorescence assay (IFA), polymerase chain reaction (PCR) or enzyme linked immunosorbent assay (ELISA) is unavailable. Currently, the Scrub Typhus Detect IgM Rapid Test of InBios Co. and the SD BiolineTsutsugamushi Kit of SD Co. are widely used as RDT. On the other hand, ImmuneMed Co. developed reliable diagnostic recombinant proteins, which were used as a diagnostic antigen for development of the Scrub Typhus RAPID in RDT type that differentially and simultaneously detects IgM and IgG. A mixed antigen originated from 5 serotypes was used the RDT which showed high sensitivities and specificities in response to antibodies from patients infected with various serotypes. Thus, it can be used as a worldwide diagnostic tool for accurate and simple diagnosis of scrub typhus.