Background
Scrub typhus is a reemerging pediatric infection becoming prevalent in hitherto nonendemic regions.Literature is scant regarding clinical phenotype and genotype correlation which could be useful in the development of future diagnostics and vaccines.
Methods
We prospectively enrolled all febrile children 2 months to 14 years presenting to Pediatric emergency at our hospital in 2 time epochs :from June 2013 to December 2014 and June 2016- December 2017 (three years) . Demographic profile and treatment history of all the children was noted. Our primary outcome was positive scrub typhus IgM assay by ELISA ( InBios International Inc., USA). Of all the samples positive for scrub typhus ELISA, serum samples were randomly selected for indirect immunofluorescence assay (IFA) for O.tsutsugamushi (Fuller Laboratories, California, USA). IFA was done to confirm the diagnosis as well as to determine the genotype of the O. tsutsugamushi prevalent in
our region. The test kit simultaneously detected and semi quantitatively determined IgM antibodies against O. tsutsugamushi using four strains namely Boryong, Gilliam, Karp and Kato.
Results
Out of 71 samples positive for scrub typhus ELISA, 15 samples were tested for IFA and of these maximum prevalence seen was of Karp genotype (8) followed by Kato (3), Boryong (1) and Gilliam (1). Two patients were mixed genotype having both Karp and Kato (1) and Karp and Boryong (1). IgM titres in most of the cases were 1:128. Six of the 8 children with Karp genotype had multisystem involvement in the form of acute undifferentiated fever, encephalopathy, hepatitis, shock, serositis and thrombocytopenia.
Conclusions
Karp was the most prevalent prototype of O. tsutsugamushi isolated which correlated with severe systemic manifestations in children.
Funding: Department of Science and Technology, Chandigarh Administration, Chandigarh, India

01 / CLINICOEPIDEMIOLOGICAL AND GENOTYPING CORRELATION OF PEDIATRIC SCRUB TYPHUS FROM CHANDIGARH, INDIA