Rickettsial infections and their clinical presentations in the Western Province of Sri Lanka: a hospital-based study

Abstract

BACKGROUND: Rickettsial infections are re-emerging. A study of the geographical distribution of rickettsial infections, their clinical manifestations, and their complications would facilitate early diagnosis.METHODS: Thirty-one selected patients from the Western Province of Sri Lanka were studied for rickettsial species, clinical manifestations, and complications. RESULTS: Of 31 patients with possible rickettsioses, 29 (94%) fell into the categories of confirmed, presumptive, or exposed cases of acute rickettsial infections (scrub typhus was diagnosed in 19 (66%), spotted fever group in eight (28%)). Early acute infection or past exposure was suggested in two (7%) cases; cross-reactivity of antigens or past exposure to one or more species was suggested in nine (31%). Seventeen out of 19 (89%) patients with scrub typhus had eschars. Nine out of 29 (32%) patients had a discrete erythematous papular rash: seven caused by spotted fever group, two by scrub typhus. Severe complications were pneumonitis in eight (28%), myocarditis in five (17%), deafness in four (14%), and tinnitus in two (7%). The mean duration of illness before onset of complications was 12.0 (SD 1.4) days. All patients except one made a good clinical recovery with doxycycline or a combination of doxycycline and chloramphenicol. CONCLUSIONS: In a region representing the low country wet zone of Sri Lanka, the main rickettsial agent seems to be Orientia tsutsugamushi. Delay in diagnosis may result in complications. All species responded well to current treatment