Epidemiological studies of urinary Schistosomiasis in Ogun State, Nigeria: Identification of high-risk communities

Abstract

The control of schistosomiasis has been hampered by lack of baseline data to demarcate communities at risk for treatment in Ogun State. This study was therefore aimed at implementing a rapid and valid epidemiological assessment of Urinary Schistosomiasis in this state, and help prioritised areas for treatment. Questionnaires were developed, pre-tested and delivered to head teachers of 1,310 state-owned primary schools, with the assistance of Local Government Primary Schools Education Authority (LGEA) respectively. Class teachers conducted interviews. School children were asked among other health problems, if they have passed blood in urine or have urinary schistosomiasis and their responses recorded as yes or no. The completed questionnaires were retrieved to the researches through LGEA within six weeks. Responses were then validated by parasitological examination of randomly collected urine sample in 50 schools for Schistosoma heamatobium eggs. A total of 101, 682 children in classes 4 to 6 were interviewed in 1,092 out of 1,310 primary schools in the state. Questionnaires retrieved rate was 83.4%. the overall mean prevalence of self-reported blood in urine and self-reported urinary schistosomiasis were 10.00%, SD = 13.84 and 7.60% SD = 12.85 respectively. Spearman rank correlation showed a highly significant association between reported blood in urine and urine filtration test (r=0.704; p<0.01). Using the 90th percentile, a state threshold of 26.75% was set resulting in the identification of 107 schools in 101 high-risk communities. Three LGAs, namely Abeokuta South, Obafemi/Owode and Yewa North LGAs should be considered as high priority LGAs for immediate intervention as these three LGAs consisted about 56% of high-risk schools in the state. The diagnostic performance of the questionnaire was high both at school/community level (Sensitivity = 0.88, Specificity = 0.82; specificity = 0.89; Positive Predictive Value = 0.95; Negative Predictive Value = 0.5) and individual level (sensitivity = 0.82, specificity = 0.89; Positive Predictive Value = 0.90; Negative Predictive Value = 0.80). This study provides for the first time a comprehensive distribution of urinary schistosomiasis in Ogun State the objective of which is to help and guide control efforts.

Nigerian Journal of Parasitology Vol. 25, 2004: 111-119