Usefulness of real-time PCR for urogenital schistosomiasis diagnosis in preschool children in a high-prevalence area in Angola

Abstract

Background Urogenital schistosomiasis caused by Schistosoma haematobium is highly endemic in the municipality of Cubal in Angola. Currently, diagnosis is based on the observation of S. haematobium eggs in urine samples by microscopy but this method has low sensitivity. Few studies have been performed using molecular techniques in high-prevalence areas for the detection of S. haematobium. The objective of this study is to evaluate the usefulness of real-time PCR as a diagnostic technique for urogenital schistosomiasis among preschool-age children and its correlation with morbidity data. Methods A cross-sectional study was conducted in Cubal, Angola, involving 97 urine samples from preschool-age children analyzed by the dipstick test, microscopic examination of filtered urine, and real-time PCR. The diagnosis of urogenital schistosomiasis was based on microscopy and/or real-time PCR results. Clinical and ultrasonography evaluation was performed to rule out complications of schistosomiasis. Results We detected a total of 64.95% of samples positive by real-time PCR and 37.11% by microscopy. The sensitivity of parasitological diagnosis of urogenital schistosomiasis by real-time PCR and microscopy was 95.45% and 54.55%, respectively, and the sensitivity of real-time PCR compared with microscopy was 91.67%. A positive real-time PCR result was significantly related to older age (mean = 3.22 years), detection of eggs by microscopy, and abnormal urine dipstick results (18.56% with proteinuria, 31.96% with leukocyturia, and 31.96% with microhematuria) (p-value<0.05). Ultrasound analysis showed that 23.94% of children had urinary tract abnormalities, and it was significantly related to the real-time PCR diagnosis (p-value<0.05). Conclusions Real-time PCR is a more sensitive technique than microscopy for urinary schistosomiasis diagnosis in preschool-age children in Cubal. This increase in sensitivity would allow earlier diagnosis and treatment, thus reducing the morbidity associated with schistosomiasis in its early stages.