Epidemiological Findings and Policy Implications from the Nationwide Schistosomiasis and Intestinal Helminthiasis Survey in Sudan

Abstract

Background: The World Health Assembly endorsed the WHO Neglected Tropical Disease (NTD) Roadmap in 2013, in which NTDs were suggested as tracers of equity in the assessment of progress towards the Sustainable Development Goals. Nationwide surveys were undertaken in all 18 states of Sudan to identify the geographical distribution and estimate the prevalence and intensity of schistosomiasis and other helminthiases from December 2016 to March 2017. Improved water and sanitation coverage at the household and school levels and the proportion of respondents who engaged in risk behaviours were assessed. Methods: Using two-stage random sampling, each locality was subdivided into one to three different ecological zones (EZs) based on proximity to water bodies. Probability-proportional-to-size sampling was used to select schools from each EZ. We estimated schistosomiasis and intestinal helminthiasis prevalence in 105,167 school children by urine concentration microscopy and Kato-Katz smears. Risk factors and the impact thereof were investigated using multi-level mixed-effect models. Findings: The overall egg-positive rates were: Schistosoma haematobium, 5·2%; S. mansoni, 0·06%; and intestinal helminths, 5·47%. Severe endemic areas were concentrated in East and South Darfur States (S. haematobium prevalence, 25·23% and 13·91%, respectively). Households and schools with latrines, and especially improved latrines (ventilated improved pit latrines or flush toilets) were associated with lower odds of schistosomiasis infection. Open defecation was strongly associated with schistosomiasis (aOR: 1·50, 95% CI: 1·35-1·66). EZ-level mass drug administration was estimated to be more cost-effective than district-level administration under all circumstances. Interpretation: Endemic schistosomiasis is concentrated in fragile border states. This study provides insight into possible programmes to effectively reduce infections by presenting possible diverse, innovative strategies to disrupt the transmission cycle. Funding Statement: This project was supported by the Korea International Cooperation Agency (KOICA) under the Integrated schistosomiasis and soil-transmitted helminthiasis control program, Sudan. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: This study protocol was reviewed and approved by the institutional review board of the Federal Ministry of Health, Sudan (FMOH/DGP/RD/TC/2016) and the Korea Association of Health Promotion (130750-20,164-HR-020).