Prevalence distribution and risk factors for Schistosoma hematobium infection among school children in Blantyre, Malawi.

Atupele P Kapito-Tembo,Sarah Radke,Victor Mwapasa,Dan Banda,Cameron Bowie,Young Samanyika,Steven R Meshnick,Jeffrey M. Bethony

doi:10.1371/journal.pntd.0000361

Atupele P Kapito-Tembo, Sarah Radke + Show 6 more

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https://doi.org/10.1371/journal.pntd.0000361

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Abstract

BackgroundSchistosomiasis is a public health problem in Malawi but estimates of its prevalence vary widely. There is need for updated information on the extent of disease burden, communities at risk and factors associated with infection at the district and sub-district level to facilitate effective prioritization and monitoring while ensuring ownership and sustainability of prevention and control programs at the local level.Methods and FindingsWe conducted a cross-sectional study between May and July 2006 among pupils in Blantyre district from a stratified random sample of 23 primary schools. Information on socio-demographic factors, schistosomiasis symptoms and other risk factors was obtained using questionnaires. Urine samples were examined for Schistosoma hematobium ova using filtration method. Bivariate and multiple logistic regressions with robust estimates were used to assess risk factors for S. hematobium. One thousand one hundred and fifty (1,150) pupils were enrolled with a mean age of 10.5 years and 51.5% of them were boys. One thousand one hundred and thirty-nine (1,139) pupils submitted urine and S. hematobium ova were detected in 10.4% (95%CI 5.43–15.41%). Male gender (OR 1.81; 95% CI 1.06–3.07), child's knowledge of an existing open water source (includes river, dam, springs, lake, etc.) in the area (OR 1.90; 95% CI 1.14–3.46), history of urinary schistosomiasis in the past month (OR 3.65; 95% CI 2.22–6.00), distance of less than 1 km from school to the nearest open water source (OR 5.39; 95% CI 1.67–17.42) and age 8–10 years (OR 4.55; 95% CI 1.53–13.50) compared to those 14 years or older were associated with infection. Using urine microscopy as a gold standard, the sensitivity and specificity of self-reported hematuria was 68.3% and 73.6%, respectively. However, the positive predictive value was low at 23.9% and was associated with age.ConclusionThe study provides an important update on the status of infection in this part of sub-Saharan Africa and exemplifies the success of deliberate national efforts to advance active participation in schistosomiasis prevention and control activities at the sub-national or sub-district levels. In this population, children who attend schools close to open water sources are at an increased risk of infection and self-reported hematuria may still be useful in older children in this region.

Highlights

Schistosomiasis remains an important public health problem globally with an estimated 200 million cases reported each year [1]
Children who attend schools close to open water sources are at an increased risk of infection and self-reported hematuria may still be useful in older children in this region
85% of the cases reported annually occur in subSaharan Africa and over 150,000 deaths are attributable to chronic infection with S. haematobium in this region [2,3]

Summary

Introduction

Schistosomiasis remains an important public health problem globally with an estimated 200 million cases reported each year [1]. Kidney failure deaths due to urinary tract scarring, deformity of ureters and the bladder caused by S. haematobium infection have become less common due to modern drugs [4,5]. Subtle and indirect morbidities such as fatigue, physical or cognitive impairment and effects of co-infections with other infectious diseases like HIV, malaria have received more attention recently [4]. New evidence from a recent review of these studies suggests a causative link between schistosome infection, anti-parasite inflammation, and risk for anaemia, growth stunting and under-nutrition, as well as exacerbation of co-infections and impairment of cognitive development and physiological capacities among infected individuals [6]. There is need for updated information on the extent of disease burden, communities at risk and factors associated with infection at the district and sub-district level to facilitate effective prioritization and monitoring while ensuring ownership and sustainability of prevention and control programs at the local level

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