Scrub typhus in an urban and semi-urban population

Abstract

OBJECTIVE: Though it had been suggested that scrub typhus could be occurring in Sri Lanka, there are no properly documented case series. We document our experience with 17 cases of scrub typhus. METHODS: All patients were admitted to the University Medical Unit in North Colombo Teaching Hospital over a period of 18 months. Diagnosis of scrub typhus was made in febrile patients by the presence of an eschar, raised antibody titres to Proteus OX-K in the Weil-Felix test and the dramatic response to specific treatment with tetracycline. RESULTS: All patients presented with high fever and the duration of the fever before diagnosis varied from three days to 21 days with a mean of 9 days. Headache and myalgia were common to all. Sixteen patients were from urban and semi-urban surroundings. All patients had the eschar and in most it was in the groin and axilla. Generalised or regional lymphadenopathy was present in all patients. In nine patients the Weil-Felix test showed raised titres to Proteus OX-K antigen. Sixteen patients were treated with tetracycline and one pregnant patient with chloramphenicol. All patients responded dramatically with fever settling within 24,hours. CONCLUSIONS: Scrub typhus seems to be commoner than thought and occurs even in urban areas. This condition has to be considered in the differential diagnosis of any patient with fever and especially when the fever is not settling early. Eschar is the most useful diagnostic sign that should be looked for.