An unexpected double burden: S. haematobium infection in the peri-urban setting outside Lusaka, Zambia

Introduction: Schistosoma haematobium is a water-transmitted parasite that causes an infection with multiple deleterious health consequences. Acute symptoms include hematuria and dysuria, while chronic infection confers increased risk for bladder cancer, infertility, genital tract lesions, and HIV transmission. Schistosomiasis affects 200 million people worldwide, of which 100 million are in sub-Saharan Africa; populations in rural or rainy environments are especially susceptible. The peri-urban settlements outside Lusaka, Zambia receive minimal government support, which contributes to overcrowding and limited access to health services and potable water. This population potentially faces high susceptibility to S. haematobium as a result of the unique risk factors in the peri-urban setting. Methods: Medical history and demographics were recorded and urine samples were collected from a convenience sample of 1,786 children and young adults (ages 2-26) as part of in-school health examinations. Results: 19.5% of the subjects had S. haematobium eggs in the urine. Of individuals with schistosomiasis, 39.3% described symptoms of infection when questioned during examination. Discussion: S. haematobium infection, while typically associated with rural and/or rainy environments, had an unexpectedly high prevalence in this peri-urban population, especially given that data collection occurred in the dry season. Lack of infrastructure in peri-urban settings may contribute to greater reliance on water sources that act as reservoirs for parasites, such as Schistosoma haematobium. Underreporting of schistosomiasis symptoms suggests that universal screening and treatment of at-risk populations, perhaps using the in-school model, is an effective way to target the unexpectedly high infection burden.