Comparison of IgM enzyme linked immuno sorbent assay with Weil-felix agglutination test for diagnosis of Scrub typhus in South India

Abstract

Introduction: Scrub typhus is a disease caused by Orientia (Rickettsia) tsutsugamushi which belongs to Rickettsiaeceae family. Early diagnosis of Scrub typhus is important because timely anti-microbial therapy may help an excellent response and prevent complications. Serology is widely used for diagnosis of scrub typhus. The Aim of this study isto detect the IgM antibodies by Capture Enzyme linked immuno sorbent assay (ELISA) and Weil –Felix agglutination test against Scrub typhus and to compare the results of IgM ELISA with Weil – Felix test. Materials and Methods:Total of 723 blood samples were collected from clinically suspected Scrub typhus patients. IgM ELISA (commercial) and Weil –Felix agglutination test for Scrub typhus were performed on all serum samples. Results: Among 723 patients, 31(4.2%) showed positive by Weil-Felix test against OX K antigen and 43 (6%) showed positive by IgM ELISA. Among 43samples which were positive by IgM ELISA, 13(1.8 %) showed negative by Weil-Felix test. Out of 31samples positive by Weil-Felix test, one sample showed negative by IgM ELISA. The sensitivity of IgM ELISA and Weil –Felix agglutination test is 96.77% and 69.76 % respectively. Conclusion:Early diagnosis and treatment will prevent complications of Scrub typhus. This study has found out the IgM ELISA is highly sensitive and dependable for diagnosis of scrub typhus than Weil –Felix agglutination test. Keywords: IgM Enzyme linked immuno sorbent assay, Scrub typhus, Weil Felix agglutination Test.