Abstract

Role of Diagnostic Testing in Schistosomiasis Control Programs in Rural Ghana

Daniel Ansong, Stephen C. Alder, Benjamin T. Crookston, Celeste Beck, Thomas Gyampomah, John H. Amuasi, Isaac Boakye, Justice Sylverken, Alex Owusu-Ofori, DeVon Hale, Alex Osei Yaw Akoto and Scott R. Larsen

Background: Schistosomiasis affects an estimated 200-300 million people worldwide. Construction of dams has contributed to the high prevalence of urinary schistosomiasis in Ghana. To assist rural villages downstream from the Barekese dam in schistosomiasis control programs, this study evaluated possible detection methods of schistosomiasis. Methods: A cross-sectional survey of volunteers was conducted in a rural setting of Ghana. Five hundred and thirty four (534) volunteers provided symptom information and urine samples for urinalysis. Microscopic egg count of 341 random samples was used to determine prevalence of disease and to analyze effectiveness of urinalysis and symptom information for diagnosing schistosomiasis. Results: Schistosomiasis prevalence was 41.1 % for the village. The highest prevalence was in the 10-14 age groups (71.1 %). Sensitivity and specificity for hematuria was 76.1 and 77.7 % respectively, and proteinuria was 58.2 & 68.7 % respectively. The positive predictive value was highest for hematuria (71.1 %). The highest negative predictive value was among positive proteinuria or hematuria (84.0 %). From urinary symptom information, reporting pain and dark urine yielded the highest positive predictive value (72.0 %). Reporting pain, difficulty, or dark urine yielded the highest negative predictive value (75.8 %). Discussion: The positive and negative predictive values of urine analysis and symptom information may be an inexpensive tool for diagnosing schistosomiasis in areas of high prevalence.