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Category: Volume 06 Issue 08 August 2018
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Title: Screening of Scrub Typhus among Patients Presenting with Pyrexia of Unknown Origin in Tertiary Care Hospital

Authors: Vasanthi.R, Chuing Lung Dup, Dr A. S. Shameem Banu

 DOI:  https://dx.doi.org/10.18535/jmscr/v6i8.27

Abstract

Scrub typhus is an endemic disease in South-east Asia and is the most important cause among undifferentiated fevers accounting for about 20-35%. Diagnosis of scrub typhus is a challenge, especially in patients with dengue fever, leptospirosis, rickettsioses, typhoid and malaria as they can present with similar signs and symptoms. Serological tests like rapid immunochromatographic tests and Weil-Felix tests are easy to perform and inexpensive, but lack specificity and sensitivity. The main aim of the study is to screen for scrub typhus by using routine serological tests, ELISA and real time PCR. A total of 32 blood samples suspected to be scrub typhus, were tested for serological assays like rapid immunochromatography, Weil-Felix and ELISA, and real time PCR for identifying 47KDa gene specific for Orienta tsutsugamushi Karp strain. A total of 100 samples were considered, which were collected from patients with fever of unknown origin. A total of 68 samples were found to be positive for various infections ruled out by routine microbiological investigations. Scrub typhus screening was done for the remaining 32, out them 12 (37.5%) samples were positive by rapid immunochromatographic test, 9 (28.1%) samples were tested positive by Weil-Felix agglutination test and 7 (21.8%) samples were positive by ELISA. All the 32 samples were selected for performing real-time polymerase chain reaction (RT-PCR), out of these 20 were positive by real-time PCR, which included the 12 samples positive by rapid immunochromatography method.

Keywords: Weil-Felix, RT- PCR, 47KDa gene, ELISA.

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Corresponding Author

Vasanthi.R

Professor, Department of Microbiology, Chettinad Hospital and Research Institute, Chennai