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 to estimate the prevalence and intensity of schistosomiasis and other intestinal helminthiases from December 2016 to March 2017. Methods We used two-stage random sampling. Each district 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 by the centrifugation method and Kato-Katz smears. Multi-level mixed-effect models were used to investigate the relationship between the prevalence of infections and risk factors, including improved water or latrine status at the household or school level. We estimated the cost-effectiveness of a one-time mass drug administration (MDA) intervention with 75% coverage at the district and EZ levels. Results A total of 105,167 students from 1772 schools were surveyed. 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. Children living in a house or attending schools with an improved latrine were less likely to be infected with schistosomiasis than those without a latrine (adjusted odds ratio, aOR: 0.45, 95% confidence interval, CI: 0.41–0.51 and aOR: 0.75, 95% CI: 0.70–0.81 at the household or the school levels, respectively). Open defecation was strongly associated with schistosomiasis (aOR: 1.50, 95% CI: 1.35–1.66). In community-wide mass treatment at the district level with an 8% threshold for schistosomiasis, 2.2 million people would not benefit from MDA interventions with 75% coverage despite high endemicity, whilst 1.7 million people would receive the MDA intervention unnecessarily. EZ-level MDA was estimated to be more cost-effective than district-level administration under all circumstances. Conclusions Our findings provide updated prevalence figures to guide preventive chemotherapy programmes for schistosomiasis and intestinal helminthiasis in Sudan. Schistosomiasis was found to be common among the inhabitants of fragile and conflict-affected areas. In addition, we found that MDA interventions would be more cost-effective at the sub-district level than at the district level, and there was a strong association between schistosomiasis prevalence and latrine status, at both the household and school levels. This study will help the Sudanese government and its neighbouring countries develop adequate control and elimination strategies.

Anaemia prevalence and determinants in under 5 years children: findings of a cross-sectional population-based study in Sudan

“…Soil-transmitted helminths and schistosomiasis are known causes of anaemia [ 32 , 33 ]. These infections are linked with access to safe water and sanitation as well as poverty [ 34 , 35 ]. However, this study did not establish any association between anaemia and access to safe water and sanitation services in Sudan.…”

“…However, this study did not establish any association between anaemia and access to safe water and sanitation services in Sudan. This may be due to the low and focal prevalence of these infections in Sudan [ 35 ].…”

Prevalence, infection intensity and geographical distribution of schistosomiasis among pre-school and school aged children in villages surrounding Lake Nyasa, Tanzania

“…The lack of epidemiological data on the Tanzanian side of the lake may present a unique challenge for the control efforts on each side of the border/lake. In addition, this has implication in the design and implementation of control measures especially MDA at this time when resources are very scarce and without data on geographical distribution of schistosomiasis, resources might be allocated to areas where they are not needed or underestimated 24 , 25 . Thus, accurate and up-to-date information on schistosomiasis infection/disease is essential for informing the design and implementation of a cost-effective control interventions and monitoring the impact of MDA at village, district, regional and national levels 24 .…”

“…In addition, this has implication in the design and implementation of control measures especially MDA at this time when resources are very scarce and without data on geographical distribution of schistosomiasis, resources might be allocated to areas where they are not needed or underestimated 24 , 25 . Thus, accurate and up-to-date information on schistosomiasis infection/disease is essential for informing the design and implementation of a cost-effective control interventions and monitoring the impact of MDA at village, district, regional and national levels 24 . In addition, describing the geographical distribution and prevalence of infection in areas bordering countries opens cross-border cooperation and collaboration to fight against neglected tropical diseases 23 .…”

“…In that context, the present cross-sectional study was conducted to determine the prevalence, infection intensities and geographical distribution of schistosomiasis (both S. haematobium and S. mansoni ) infection among pre-school aged children and school aged children living in villages surrounding Lake Nyasa, in Nyasa District, Southern Tanzania. Understanding the prevalence and geographical distribution not only help in identifying high risk communities but also help in planning and implementation of mass drug administration based on level of infection 24 .…”