Emergence of Scrub Typhus in Urban Areas: a Report from South India

Aims: To study the epidemiology and clinical presentation of Scrub typhus in Southern India.

Study design: Observational study

Place and Duration of Study: Apollo Hospital, Chennai, India, between January 2010 and December 2011.

Methodology: This is an observational study of 182 patients from a tertiary care center between January 2010 and December 2011. Cases of scrub typhus were defined by a positive IgM scrub typhus ELISA, compatible clinical features and negative workup for other pathogens. Epidemiological data and clinical data were collected from the records for the study purpose.

Results: Fever (100%), headache (69.7%) and cough (47.8%) were the predominant presenting symptoms. The majority (85.7%) of cases were during the period from July to December in both the years, corresponding to the monsoon in South India. 62% of cases were from urban areas and 47.3 % of cases required admission to the critical care unit. An eschar was present in 46.7% of cases and 97.3% of the cases improved with therapy. All patients received either doxycycline or azithromycin or a combination of both as therapy. Defervescence was seen within 72 hours in 98.5% of patients.

Conclusion: Scrub typhus is a re-emerging disease in South India. It should be considered in the differential diagnosis of acute undifferentiated febrile illness even in urban areas in all age groups, especially during the monsoon season. Careful search for an eschar is important. Treatment with doxycycline or azithromycin is effective. The mortality rate is expected to be high if untreated, so we suggest that these antibiotics be part of initial empiric therapy whenever the disease is in the differential diagnosis in all severely ill patients awaiting diagnostic results.