Clinical and Sero-immunological Profile of Scrub Typhus in Bengaluru, Southern IndiaCorrespondence Address :
Dr. Sneha K Chunchanur,
Department of Microbiology, Victoria Hospital Campus Fort, Bengaluru, Karnataka, India.
Introduction: Scrub typhus is a common but neglected cause of Acute Febrile Illness (AFI) in India. Under diagnosis of this severe disease with protean manifestations, can negatively influence the treatment and outcome. Early laboratory diagnosis by appropriate means is therefore important. In addition, as antigenically diverse variants of Orientia tsutsugamushi (O.tsutsugamushi) are known to exist and evolve, information regarding the strain types is also crucial.
Aim: Present study sought to know the clinical spectrum, laboratory diagnosis by different modalities, outcome and strain variation of scrub typhus in Southern India.
Materials and Methods: Hundred clinically suspected cases of scrub typhus (rickettsioses) were enrolled. Serum and EDTA (Ethylenediaminetetraacetic acid) blood samples were subjected to serodiagnosis for scrub typhus and Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) respectively. Strain characterisation was done by Microimmunofluorescence (MIF), PCR-RFLP and phylogenetic analysis. Patients were followed-up for four weeks. Data was entered in Microsoft excel spreadsheet and analysed using Statistical Package for the Social Sciences (SPSS) software.
Results: Laboratory evidence of scrub typhus was showed by 38% of the cases. Seropositivity was more in comparison to PCR. Paediatric preponderance and seasonal trend was evident. Strain typing showed presence of different strain types, with no correlation between clinical features and strain types. PCR-RFLP results correlated well with phylogeny, while MIF results did not match. All the patients responded to doxycycline, except for 12% who succumbed.
Conclusion: Different strain types of O. tsutsugamushi are known to cause scrub typhus in Southern India. PCR-RFLP can be a useful preliminary tool for strain typing in resource poor settings, where phylogenetic analysis is not possible. Early diagnosis and treatment helps in improved outcome.
Doxycycline, Microimmunofluorescence, Orientia tsutsugamushi, Polymerase chain reaction-restriction fragment length polymorphism
Date of Submission: May 23, 2020
Date of Peer Review: Jun 27, 2020
Date of Acceptance: Jul 27, 2020
Date of Publishing: Sep 01, 2020
• Financial or Other Competing Interests: As declared above
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. Yes
PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: May 25, 2020
• Manual Googling: Jul 16, 2020
• iThenticate Software: Aug 27, 2020 (15%)
ETYMOLOGY: Author Origin
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