Incidence of Scrub Typhus in a Tertiary Care Hospital in Uttarakhand.

Context: Scrub typhus is an important cause of acute undifferentiated febrile illness. Due to non specific clinical presentation cases are often missed, although endemic in our country. IgM Ab detection by ELISA and Rapid Immunochromatographic test (ICT) are commonly employed for its diagnosis. Aim: To study the incidence of Scrub typhus in population attending our hospital in Uttarakhand. Settings and Design: This prospective study was carried out from September 2013 to November 2013 in cases of PUO with high suspicion of scrub typhus. Material and Methods: A total of 294 samples were subjected to a spectrum of tests(ICT for antibodies against Orientia tsutsugamushi, IgM, IgG Ab & NS1Ag for Dengue, IgM to Salmonella Typhi) based on clinical suspicion of febrile illness. Positive samples for Orientia tsutsugamushi were retested by ELISA for IgM antibodies against O. tsutsugamushi. Results: Out of 294 cases of PUO, 61 /294 (20.7%) were found to be positive for IgM Ab to Orientia tsutsugamushi, 27 /294 (9.18%) IgM, IgG Ab & NS1Ag for Dengue, and one out of 294(0.003%) for IgM Ab to Salmonella Typhi. One case was found to be reactive for both IgM Ab for Orientia tsutsugamushi and Dengue. Data was analyzed in correlation with clinical features. Conclusions: This study implies emergence of scrub typhus in our region. It is thus suggested that high index of suspicion for scrub typhus should be maintained for cases presenting with acute febrile illness to avoid false negative reporting owing to absence of eschar formation which is pathognomic feature of disease and rarely seen in Indian sub-continent.