Scrub Typhus: A Cause for Pyrexia of Unknown Origin-Scenario in Chennai City, South India

Abstract

Background. Scrub typhus is re-emerging vector borne zoonotic disease in India. It is grossly under diagnosed and its awareness among clinicians is limited. Few reports has been published on the prevalence of scrub typhus in Chennai. The objective of this study was to identify scrub typhus infections in patients with Pyrexia of Unknown Origin (PUO) cases in Chennai, South India. Methods. This was a prospective study. Patients with fever who presented to the Department of Experimental Medicine at T.N. Dr. M.G.R. Medical University between November 2015 and February 2016 were enrolled. Demographics and clinical symptoms and signs were recorded using a semi structured questionnaire. Under aseptic precautions, 2 ml of blood was collected by venipuncture and serum was separated and stored at 4degreeC for further testing. The scrub typhus Detect ELISA test was performed to detect IgM antibodies against Orientia tsutsugamushi. Data was analyzed using mean and percentages. Results. A total of 100 patients were enrolled and their age ranged from 4 to 80 years with a mean of 30 years (SD 21). Fifty-six percent were males and 44% were females. Twenty-three percent (23 of 100) were positive for IgM antibodies against O. tsutsugamushi. Most (65%) of the positive patients were females. Majority of the patients (48%) positive for scrub typhus were in the younger age group (4-20 years) followed by patients in the age group 20-30 and 40-50 years with 17% in each group. About 65% had myalgia and 61% of patients suffered headache, nausea and cough. Nearly 48% developed vomitting and abdominal pain. Infrequent complaints were breathlessness, diarrhea, jaundice, altered sensorium and rashes. The pathognomonic feature such as eschar was seen only in 3 patients. Five patients were also positive for Salmonella typhi. Conclusion. In the present study, 23% of patients were positive for scrub typhus infection. Hence scrub typhus infection should be considered as differential diagnosis in PUO cases in Chennai city.