Urogenital schistosomiasis prevalence and diagnostic performance of urine filtration and urinalysis reagent strip in schoolchildren, Ethiopia

Abstract

Background Urogenital schistosomiasis has been known to be endemic in several lowland areas of Ethiopia. It is caused by Schistosoma haematobium and causes considerable public health problems to schoolchildren. Ethiopia, after mapping the distribution of the disease (2013 to 2015), launched school-based mass deworming program to treat schoolchildren for schistosomiasis and soil-transmitted helminthiasis (STH) across the country since 2015. However, there is no recent information about the prevalence of the disease among schoolchildren in the current study areas. Diagnostic performance of urine filtration method and urinalysis reagent strip is also lacking. Therefore, this study aimed to determine the prevalence of urogenital schistosomiasis in schoolchildren, and to evaluate diagnostic performance of urine filtration and urinalysis reagent strip in Amibara, Kurmuk and Abobo districts, Ethiopia. Methods Across-sectional study was conducted involving 1,171 schoolchildren in Abobo, Amibara and Kurmuk districts from October, 2020 to January, 2021. The study participants were selected using random sampling technique. From each study participant, 10 ml urine samples were collected and examined using urine filtration method and urinalysis reagent strip. Data obtained from the survey were entered into Microsoft Excel 2010 and analysed with SPSS version 20.0. Data was summarized using descriptive statistics. Chi-square, bivariate and multivariable logistic regression and Pearson correlation test were used to measure associations between urogenital schistosomiasis, age, sex and haematuria. Odds ratio was used to measure strengths of association between variables. Agreement between urine filtration method and urinalysis reagent strip was determined using Kappa statistics. P-value < 0.05 at 95% CI was considered as statistically significant. Results Among the 1,171 urine samples from schoolchildren examined by urine filtration method, 143 (12.2%) were S.haematobium egg positive. Out of 143 positive children 126(88.1%) were lightly infected and 17 (11.9%) were heavily infected. Among the total of 1,171 urine samples tested by dipstick, 264(22.5%) were positive for haematuria. Prevalence of urogenital schistosomiasis by both urine filtration and urinalysis reagent strip method was higher in Abobo than Hassoba (Amibara) and Kurmuk (P< 0.001). The number of egg counts (intensity of infections) were significantly correlated with intensity of haematuria (r = 0.6, P < 0.001). Egg-positive children had significantly higher risk of having haematuria compared to S. haematobium egg negative children (OR; 6.96; 95%CI: 4.98, 8.940). Compared to urine filtration method, the sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) of urinalysis reagent strip were 99.3%, 88.1%, 53.8% and 99.8%, respectively. Furthermore, its positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 8.34 and 0.008, respectively. The accuracy index and diagnostic odds ratio (DOR) of reagent strip were 0.89 and 1054, respectively. The agreement level between urine filtration methods and urinalysis reagent strip for detecting urogenital schistosomiasis was substantial (Kappa = 0.64). Conclusion This study showed that urogenital schistosomiasis was prevalent in schoolchildren in Abobo, Hassoba and Kurmuk districts. Urogenital schistosomiasis prevalence in Hassoba-bure and Kurmuk falls under low category whereas moderate in Abobo and is almost four times compared to Kurmuk and Hassoba-bure. Chemotherapy is needed in schoolchildren in such endemic areas and other measures like access to safe water, improved sanitation, hygiene, and health education should be implemented to control and prevent schistosomiasis effectively. The sensitivity, specificity, positive and negative predictive values of urinalysis reagent strip were higher and could serve as alternative for mass screening of urogenital schistosomiasis, for surveillance and evaluation of schistosomiasis intervention programs.

Performance of Urine Reagent Strips in Detecting the Presence and Estimating the Prevalence and Intensity of Schistosoma haematobium Infection

“…In sum, the agreement of the URS with the urine filtration method in detecting the presence and estimating the classes of the intensity of S. haematobium infection was substantial (percent agreement = 84.4 and 78.4, respectively). A similar previous study also reported a similar level of agreement (Kappa = 0.64) between the URS and urine filtration in detecting the presence of S. haematobium infection in children [ 9 ].…”

“…A review article that combined 74 studies (102,447 participants) also estimated a 75% sensitivity and 87% specificity for detecting hematuria using URS applying a urine filtration microscope as a reference [ 14 ]. Two studies conducted in the current study area reported a higher sensitivity (>89%) of URS in detecting S. haematobium infections [ 7 , 9 ]. The decrease in the sensitivity of the URS in identifying individuals infected with S. haematobium in the current study could be due to the low intensity of infections that may have a negligible impact on the amount of blood in the urine, ‘hematuria’.…”

“…Some inhabitants practice small-scale irrigation along the Awash River and live nearby the large-scale irrigation-based cotton farm of the Middle Awash Valley. The study villages were selected based on their endemicity for S. haematobium infection [ 7 , 8 , 9 ], location near the Awash River or Alwero river (Abobo district), and availability of irrigation canals and swamps. School-age children living in the selected villages from October 2021 to April 2022 were eligible for the study.…”

“…The prevalence of S. haematobium infection reported among children was 35.9% in those living in Abobo primary school in Gambella Regional State [ 5 ], 20.8% in those living in seven villages of Afar Regional State [ 7 ], and 47.6% in those living in Hassoba [ 8 ]. Another study also reported S. haematobium with a prevalence of 24.2% among children in Abobo village of Gambella Regional State, 5.6% among children in Kumruk village of Beneshangul Gumuz Regional State, and 7.0% among children in Hassoba-Buri village of Afar Regional State [ 9 ]. Despite the ongoing preventive treatment of school-age children using praziquantel since 2015 [ 10 ], studies done so far reveal that urogenital schistosomiasis remains a public health threat in at least the three regional states of the country [ 5 , 6 , 7 , 8 , 9 ].…”

“…Detection of hematuria using a reagent strip could particularly be useful for testing S. haematobium infection in school-aged children, as hematuria in children will strongly correlate with urogenital schistosomiasis [ 14 ]. However, the sensitivity of the URS in detecting S. haematobium infection showed variation in the prevalence and intensity of infection [ 7 , 9 , 14 ]. In this study, we examined the performance of the URS in detecting the presence and estimating the prevalence and intensity of S. haematobium infection among school-age children in selected study sites in Afar and the Gambella Regional States of Ethiopia that have been shown to have varied intensity of infection.…”