The COUNTDOWN Study Protocol for Expansion of Mass Drug Administration Strategies against Schistosomiasis and Soil-Transmitted Helminthiasis in Ghana

(1) Background: Current international policy for schistosomiasis and soil-transmitted helminthiasis (STH) control emphasises mass administration of deworming drugs in school-based programmes. However, this approach is insufficient to control the transmission of these diseases, and their burden in non-school cohorts is recognised, albeit under-researched. This research will investigate the feasibility and acceptability of expanding access to praziquantel (PZQ) against schistosomiasis, and albendazole (ALB) against STH, to communities in selected transmission settings in Ghana. (2) Methods: A three-site longitudinal study will be implemented to investigate the effectiveness of expanding treatment strategies for PZQ and ALB to community members. In the context of community mass drug administration (to preschool children, school non-attending children, and adults, including pregnant women), the intervention will be assessed in a random sample of community members, at baseline with follow-up at 6, 12, and 18 months. In each community, 658 participants will be enrolled, and 314 followed up at each time point. The primary outcome measure is the prevalence of infection of Schistosoma haematobium and/or S. mansoni at study endpoint, as assessed by longitudinal surveys. Secondary outcomes are to quantify the infection of schistosomiasis and STH infections in non-treated cohorts, reductions in prevalence of STH, and intensity of schistosomiasis and STH, and treatment coverage. Nested within this study will be qualitative, cost-benefit, and cost-effectiveness evaluations that will explore accessibility, feasibility, and economic impact of expanded treatment from different complementary perspectives. (3) Discussion: Using a multidisciplinary approach, this study will generate evidence for improved availability, acceptability, affordability, and accessibility to deworming drugs against schistosomiasis and STH to individuals and communities in Ghana. This is likely to have considerable research, programmatic, and political value to contribute evidence for national programme policy development within Ghana, and, more broadly, World Health Organization policy development.

Schistosomiasis

Schistosomiasis is the second most important parasitic disease in the world in terms of public health impact. Globally, it is estimated that the disease affects over 200 million people and is responsible for 200,000 deaths each year. The three major schistosomes infecting humans are Schistosoma mansoni, S. japonicum, and S. haematobium. Much immunological research has focused on schistosomiasis because of the pathological effects of the disease, which include liver fibrosis and bladder dysfunction. This unit covers a wide range of aspects with respect to maintaining the life cycles of these parasites, including preparation of schistosome egg antigen, maintenance of intermediate snail hosts, infection of the definitive and intermediate hosts, and others. The unit primarily focuses on S. mansoni, but also includes coverage of S. japonicum and S. haematobium life cycles.

Schistosomiasis

The trematode parasites in the family Schistosomatidae (phylum Platyhelminthes) infect a wide range of vertebrates. Three species of the genus Schistosoma are of major medical importance. This unit deals exclusively with the parasite Schistosoma mansoni, which is the species most frequently maintained in the laboratory. Among the far-ranging investigations in the immunology of schistosomiasis are studies in vaccine development, immunopathology of granulomatous inflammation and fibrosis, eosinophil function, and in vivo regulation of T(H)1 and T(H)2 responses. This unit describes maintenance and collection procedures for various stages of the schistosome that have immunologic interest, including infection of mice with cercariae, collection of cercariae, preparation of in vitro-derived schistosomules and in vivo-derived schistosomules, and collection of adult worms and eggs. Included also are techniques for preparing soluble egg antigen (SEA), one of the more commonly used schistosome antigenic preparations. A discussion is given of the basic steps that are important in maintaining the snail intermediate host, and infecting the snails with schistosome miracidia. The unit deals exclusively with the parasite Schistosoma mansoni, which is the species most frequently maintained in the laboratory. Since part of the life cycle of all schistosomes involves a snail host, a description of proper maintenance for the snails is provided. Often, problems in experiments can be traced back to improper snail and parasite maintenance, or lack of attention to detail during mammalian exposure to the infective stage (cercaria) of the parasite.