A cross-sectional study on schistosomiasis prevalence, intensity and risk factors in Kassala State, Sudan

Despite decade-long global efforts, schistosomiasis remains a significant concern in Sudan. In 2017, a nationwide survey on schistosomiasis raised concerns about the existence of persistent "hot spot" areas that require more focused interventions and resources. The Sudanese Federal Ministry of Health (FMOH) and the Kassala State Ministry of Health have continued to implement school-based MDA. This study aimed to assess the prevalence and intensity of Schistosoma mansoni and S. haematobium infections and to identify associated demographic and environmental risk factors in high-endemic communities in Kassala State, Sudan. We conducted a community-based cross-sectional survey between 24th January and 13th February 2023 across 40 purposively selected villages in New Halfa and Nahr Atbara localities. Stool and urine samples were collected from 3,889 residents of all ages. S. mansoni infection was diagnosed via the Kato-Katz technique, and S. haematobium via urine centrifugation. Prevalence and infection intensity were modeled using a double hurdle model. Additional sociodemographic and behavioral data were collected through structured household interviews. The prevalence of Schistosoma mansoni in New Halfa and Nahr Atbara was 28.0% and 24.3%, respectively. In contrast, the prevalence of Schistosoma haematobium was relatively low, with a rate of 2.1% in New Halfa and no infections detected in Nahr Atbara. For S. mansoni, one village exhibited the highest prevalence of 68.2%. Out of 40 villages identified as potential hotspots, 25 had a prevalence exceeding 20%. In contrast, S. haematobium was found in only a few villages in New Halfa, with prevalence surpassing 10% in two of the 40 villages. The prevalence of infection among individuals aged 20 and older remained high in the identified villages. These findings suggest that the current mass drug administration (MDA)-only approach, which focuses primarily on school-aged children, is insufficient to prevent persistent reinfection at the local level. Therefore, updated guidelines tailored to the national context, expanded MDA with microplanning, awareness campaigns across all age groups, and improvements in water and sanitation are crucial components for effective schistosomiasis control. Moreover, the interruption of annual MDA programs due to civil conflict and reduced access to medication has exacerbated the situation, underscoring the urgent need for international attention and support.