Study and implementation of urogenital schistosomiasis elimination in Zanzibar (Unguja and Pemba islands) using an integrated multidisciplinary approach

Abstract

BackgroundSchistosomiasis is a parasitic infection that continues to be a major public health problem in many developing countries being responsible for an estimated burden of at least 1.4 million disability-adjusted life years (DALYs) in Africa alone. Importantly, morbidity due to schistosomiasis has been greatly reduced in some parts of the world, including Zanzibar. The Zanzibar government is now committed to eliminate urogenital schistosomiasis. Over the next 3–5 years, the whole at-risk population will be administered praziquantel (40 mg/kg) biannually. Additionally, snail control and behaviour change interventions will be implemented in selected communities and the outcomes and impact measured in a randomized intervention trial.Methods/DesignIn this 5-year research study, on both Unguja and Pemba islands, urogenital schistosomiasis will be assessed in 45 communities with urine filtration and reagent strips in 4,500 schoolchildren aged 9–12 years annually, and in 4,500 first-year schoolchildren and 2,250 adults in years 1 and 5. Additionally, from first-year schoolchildren, a finger-prick blood sample will be collected and examined for Schistosoma haematobium infection biomarkers. Changes in prevalence and infection intensity will be assessed annually. Among the 45 communities, 15 were randomized for biannual snail control with niclosamide, in concordance with preventive chemotherapy campaigns. The reduction of Bulinus globosus snail populations and S. haematobium-infected snails will be investigated. In 15 other communities, interventions triggering behaviour change have been designed and will be implemented in collaboration with the community. A change in knowledge, attitudes and practices will be assessed annually through focus group discussions and in-depth interviews with schoolchildren, teachers, parents and community leaders. In all 45 communities, changes in the health system, water and sanitation infrastructure will be annually tracked by standardized questionnaire-interviews with community leaders. Additional issues potentially impacting on study outcomes and all incurring costs will be recordedand monitored longitudinally.DiscussionElimination of schistosomiasis has become a priority on the agenda of the Zanzibar government and the international community. Our study will contribute to identifying what, in addition to preventive chemotherapy, needs to be done to prevent, control, and ultimately eliminate schistosomiasis, and to draw lessons for current and future schistosomiasis elimination programmes in Africa and elsewhere.Trial registrationISRCTN48837681

Advocacy, policies and practicalities of preventive chemotherapy campaigns for African children with schistosomiasis

“…SCORE projects included both field and laboratorybased efforts framed with a concept of 'gaining and sustaining control' where different treatment regimes with PZQ were investigated and how these might best synergize with alternatives for example, health education [75]. A flagship project is an ambitious attempt to eliminate urogenital schistosomiasis from Zanzibar where PZQ treatment of school-children is intensified and used alongside molluscicides with the hope of eliminating morbidity and local transmission [76][77][78]. Nested within these projects are those to evaluate present rapid diagnostic tests, namely the circulating cathodic antigen urine dipstick, which is the only commercially available test for intestinal schistosomiasis, as well as, developing new test formats with other circulating antigens [75].…”

Water-based interventions for schistosomiasis control

“…8,9 Although a vaccine for schistosomiasis is a popular aspiration as an adjunct control approach and many investigators are working toward this goal, no vaccines for human schistosomiasis currently exist. 10 …”

“…Despite these drawbacks, the combination of mollusciciding and praziquantel treatment is more effective for reducing prevalence of schistosomiasis in humans than is treatment alone and it is currently being employed in operational research for elimination of schistosome infections in some areas. 8,32 Indigenous plant extracts are an attractive alternative to chemicals for killing snails. Costs are held down by local availability and the extracts are less toxic to other forms of aquatic life.…”

“…Upon release from the snail, the infective cercariae swim, penetrate the skin of the human host (6), and shed their forked tail, becoming schistosomulae (7). The schistosomulae migrate through several tissues and stages to their residence in the veins (8,9). Adult worms in humans reside in the mesenteric venules in various locations, which are specific for each species (10).…”

An Integrated Approach to Control Soil-Transmitted Helminthiasis, Schistosomiasis, Intestinal Protozoa Infection, and Diarrhea: Protocol for a Cluster Randomized Trial (Preprint)

“…In view of the current discussion and efforts to shift from morbidity control to interruption of transmission of neglected tropical diseases, ongoing efforts need to be intensified, along with concurrent implementation of complementary interventions [4][5][6][7]. Indeed, integrated approaches, combining preventive chemotherapy with water, sanitation and hygiene (WASH), and information, education and communication (IEC) are necessary to sustain the gains made in the control of helminthiases and eventually break transmission [8][9][10][11].…”