Serological Evidence of Spotted Fever Group Rickettsial infection in North Karnataka Region

Background: Rickettsial diseases are important reoccurring infections that mostly go unnoticed or misdiagnosed due to low manifestation, non specific signs, symptoms and absence of widely available sensitive and specific tests. Failure of timely diagnosis leads to significant morbidity and mortality. Though the disease is rampant throughout the world, only few case reports and studies have been reported from only some states of India in the past 15-20 yrs. Aim and Objectives: To demonstrate the serological evidence for the existence of Spotted fever group Rickettsial infections in North Karnataka region and to develop a preliminary understanding of the distribution of these infections. Materials and Methods: During the period of 2015-16, a total of 231 patients sample presenting with consistent fever of more than 8 days, headache, myalgia, rashes and eschar were examined for Rickettsial infections by Weil Felix agglutination test. Further all the WF positive samples were screened for corresponding antibodies to SFG R. conorii by specific serological test IgM/ IgG ELISA. Results obtained with both the methods were tabulated. Results: Out of 231 cases, 105 samples showed agglutinins with Weil Felix antigens. 84 (36.36%) samples had titres ranging from 1:80 to 1:320 with OX2 antigen alone, 5 (2.16%) samples had titres of 1:80 and above for OX19 antigen and 16 (6.92%) samples had titres of 1:80 and above with both OX2 AND OX19 antigens. In R. conorii specific IgM ELISA 27 (25.7%) samples were positive with index >11 and 4 samples had equivocal index value. 74 samples were negative for R. conorii specific antibodies by ELISA. Conclusion: Findings of our study clearly demonstrated that among Rickettsial infections, SFG R. conorii infection seems to be common infection in and around Vijayapur. Inclusion of specific IgM ELISA method in routine diagnostic course is highly necessary for the proper treatment and patient management.