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 costeffective at the sub-district level than at the district level, and there was a strong association between schistosomiasis

Prevalence and Intensity of Urinary Schistosomiasis Among Selected People in Tulus Area, South Darfur State, Sudan

“…In contrast, the present study showed very much higher prevalence of S. haematobium compared to that obtained from nationwide survey (5.2%), even though, South Darfur States was the second most endemic area with a prevalence of 13.91% in that survey (9). Moreover, many other nding across the country reported lower ndings when the S. haematobium diagnostic stages were screened particularly among children (11,16,17).…”

“…A recent nationwide survey carried out in all the states estimated that the overall prevalence of S. haematobium was 5.2%. The same survey pointed East and South Darfur States as most severe endemic areas (9). However, there are limited data on the burden of the disease in these areas.…”

“…Although, in the 1970s, schistosomiasis was reported to be endemic in the western area of Darfur [9], there have been few detailed surveys and published data in this region, particularly during the years overwhelmed by the civil war. Therefore, this study was conducted to provide preliminary information in regard to S. haematobium prevalence in a limited study population recruited form the city of Tulus, South Darfur state which can help in improving schistosomiasis control in the area.…”

Reduction patterns of prevalence and intensity of Schistosoma haematobium infection after MDA with praziquantel between regions with and without previous intervention in Sudan

“…haematobium infection in the White Nile State (21.4%) in 1996 [11] and the baseline prevalence in Al Jabalain before MDA in 2009 (28.5%) [9]. Although the two localities had different MDA histories, the chemotherapeutic effect of a single praziquantel MDA was good and stable based on the observed reduction rate of prevalence.…”

“…Sudan has one of the highest schistosomiasis prevalence rates in the world. About 15% of the total population (~ 5.8 million people) requires treatment, with the majority being children [11,12].…”