Serodiagnosis and Molecular Characterization of Scrub Typhus in and around Vijayapura, North Karnataka Region Hegde M.L. Shriharsha1, Peerapur Basavaraj V.2, Sharif Nazeer3, Hoti S.L.4 1Scholar, Department of Microbiology, BLDEUs Shri B.M. Patil Medical College, Vijayapura 2Professor & Head Department of Microbiology, Raichur Institute of Medical Sciences, Raichur 3Research Associate, ICMR-National Institute of Traditional Medicine, Belagavi 4Scientist ‘G’, Director In-charge, ICMR-National Institute of Traditional Medicine, Belagavi, Karnataka *Corresponding Author: Shriharsha Hegde M.L. Ph. D. Scholar, Department of Microbiology, BLDEUs Shri B.M. Patil Medical College, Vijayapura, Karnataka e-mail: harsha.cadet@gmail.com
Online published on 23 December, 2019. Abstract Background Scrub typhus or tsutsugamushi disease, transmitted by the bites of infected immature mites (chiggers) is a most covert re-emerging febrile infection currently. The disease is unnoticed or misdiagnosed due to low manifestation and lack of specific diagnostic tests at all levels. Failure of timely diagnosis leads to significant morbidity and mortality. Geographically this disease is widely endemic in a confined area of the Asia-Pacific region. In India, Scrub typhus infection is increasing and reported from various geographical parts during the past 10–15 yrs. Serological test is widely used for the diagnosis of the disease. Aim & Objectives To investigate the presence of Scrub typhus infection in and around Vijayapura of North Karnataka region using serological tests and nested PCR. Materials and Method During the period of 2015–17, a total of 209 patients presenting with acute febrile illness with rashes, body ache were examined for Scrub typhus infections by Weil Felix agglutination test and IgM ELISA. Further all the ELISA positive sampleswere tested by nested PCR using the specific primers of the gene encoding the immunodominant 56 kDa protein and PCR products were sequenced. Results Out of 209 cases, 39 (18.5%) samples showed agglutinationin Weil Felix antigen OXK test with titre 1: 160 and above. In Scrub typhus IgM ELISA 13 (6.3%) samples were positive with the OD value more than 0.5. In nested PCR, two samples were amplified a 483 base pairs diagnostic segment of the gene encoding the 56 kDa antigen of O. tsutsugamushi using specific primers. PCR product was sequenced bidirectionally, and nucleotide sequences queried against NCBI BLAST programme to identify the sequenced sample. Conclusion Findings of our study demonstrated that, though more seropositivity of Spotted Fever Group Rickettsial infection is observed by WF test, scrub typhus infection is also circulating and causing acute febrile illness in and around Vijayapura, North Karnataka region. As the routinely used Weil felix test is less sensitive, inclusion of more specific tests like ELISA and nested PCR is very useful in proper diagnosis and patient management. Top Keywords Weil Felix test, Rickettsia, Scrub typhus, ELISA, Nested PCR. Top |