The diagnostic potential of three indirect tests for urinary schistosomiasis in Nigeria

Abstract

Schistosomiasis is one of the major parasitic infections of man in the tropical and subtropical areas of the world. Diagnosis of the disease is usually based on microscopic detection of eggs in excreta which is both laborious and time consuming. In Nigeria, the Government's emphasis on the control of the disease dictates the need for a simple, fast, reliable and affordable diagnostic test for the identification of infected communities and detection of infected persons. Three indirect diagnostic tests for urinary schistosomiasis: interview technique, visual examination for macrohaematuria and the use of a chemical reagent strip were employed in screening 1056 individuals of the Kainji Lake area of Nigeria for urinary schistosomiasis, using haematuria as the disease indicator. The sensitivity of the three tests were determined using the filtration (egg counting) technique as the reference test. The sensitivity of the reagent strip test was 69.0% and 44 and 38% for the interview technique and visual examination respectively. The reagent strip test was particularly useful for screening children (5-19 years old). The implication of these findings are discussed.

PIP: In Nigeria, where control of schistosomiasis is a public health goal, diagnosis based on microscopic detection of eggs in excreta is both labor-intensive and time-consuming. The present study evaluated the diagnostic potential of 3 indirect tests for urinary schistosomiasis in 1056 children and adults from Nigeria's Kainji Lake area: interview technique, visual examination for macrohematuria, and use of a chemical reagent strip. Sensitivity was determined through use of the filtration (egg counting) technique as the reference diagnosis. Sensitivity was 69% for the reagent strip test, 44% for the interview technique, and 38% for visual examination. The reagent strip was particularly sensitive for screening children 5-19 years of age. All 3 tests showed increases in sensitivity with increases in infection intensity.