Validation of the World Health Organization's Rapid Assessment Method for Urinary Schistosomiasis in Southeastern Nigeria

Abstract

Urinary schistosomiasis is a helminth disease that causes high morbidity in endemic areas of tropical and subtropical regions. Efforts are being made to evolve a cost-effective method for diagnosing the infection in large populations. A study supported by the World Health Organization (WHO) has established the Rapid Assessment (Questionnaire) method in which diagnosis is based on the respondent's ability to answer yes to the presence of hematuria. This method has been validated in some African countries and elsewhere. The aim of the present study was to validate the Rapid Assessment method in a community in southeastern Nigeria where the disease is endemic. A survey was carried out using both the parasitological diagnosis of the presence of the characteristic egg of Schistosoma haematabium in urine samples and the WHO Rapid Assessment method. Positive results in the 2 methods were calculated as percentages, and a correlation analysis of the percentages was done using product moment statistics. This gave a significant value of r = 2.9435 (P < 0.05). Sex-related prevalence was observed at significant correlation values of r = 1.0011 and r = 1.574 (P < 0.05). The diagnostic performance of the Rapid Assessment method was calculated using Baker's procedure method. A high sensitivity of 93.4%, specificity of 99%, positive predictive value of 96.6%, and negative predictive value of 99.4% were calculated. The consistent high correction performance values confirm that the Rapid Assessment method may be a useful alternative to the parasitological tests for use in schools and community surveys in identifying high-risk individuals for urinary schistosomiasis in southeastern Nigeria.