Seroepidemiological investigations on typhus in Mekele, Dessie and the nearby towns

Abstract

A seroepidemiological study on typhus was conducted in Dessie, Mekele and the nearby towns. A total of 792 serum specimens were collected from patients with acute febrile illness who came to seek treatment in hospitals, health centres and malaria control centres. Also, 246 blood specimens were collected from apparently healthy individuals who donated blood to the blood banks of Dessie and Mekele. The specimen collection was performed during the rainy (July 31 - Sept. 3, 1993) and during the dry (May 21 - June 21, 1994) seasons. All specimens were tested by the WeilFelix test and the Enzyme Linked Immunosorbent Assay (ELISA) for IgM antibodies specific to Rickettsia prowazekii. The disease prevalence was significantly higher during the rainy season than the dry season. A Weil-Felix test positivity of 5.3% and 13.5% in Mekele (OR=2.78, P0.05) were found during the dry and rainy seasons, respectively. Among the various occupational groups, higher prevalence was observed in the student population (up to 36%). A general prevalence which ragned from 6% to 9% and 10% to 22% was observed in blood donors from the two towns by the Weil-Felix test and IgM ELISA respectively. The seroprevalence observed in the various groups, the seasonality of the disease as well as the importance of laboratory diagnostic methods have been discussed in relation to possible future outbreaks of epidemic typhus