Schistosomiasis — Assessing Progress toward the 2020 and 2025 Global Goals

Abstract

BACKGROUNDWith the vision of "a world free of schistosomiasis," the World Health Organization (WHO) set ambitious goals of control of this debilitating disease and its elimination as a public health problem by 2020 and 2025, respectively. As these milestones become imminent, and if programs are to succeed, it is important to evaluate the WHO programmatic guidelines empirically. METHODSWe collated and analyzed multiyear cross-sectional data from nine national schistosomiasis control programs (in eight countries in sub-Saharan Africa and in Yemen). Data were analyzed according to schistosome species (Schistosoma mansoni or S. haematobium), number of treatment rounds, overall prevalence, and prevalence of heavy-intensity infection. Disease control was defined as a prevalence of heavy-intensity infection of less than 5% aggregated across sentinel sites, and the elimination target was defined as a prevalence of heavy-intensity infection of less than 1% in all sentinel sites. Heavyintensity infection was defined as at least 400 eggs per gram of feces for S. mansoni infection or as more than 50 eggs per 10 ml of urine for S. haematobium infection. RESULTSAll but one country program (Niger) reached the disease-control target by two treatment rounds or less, which is earlier than projected by current WHO guidelines (5 to 10 years). Programs in areas with low endemicity levels at baseline were more likely to reach both the control and elimination targets than were programs in areas with moderate and high endemicity levels at baseline, although the elimination target was reached only for S. mansoni infection (in Burkina Faso, Burundi, and Rwanda within three treatment rounds). Intracountry variation was evident in the relationships between overall prevalence and heavy-intensity infection (stratified according to treatment rounds), a finding that highlights the challenges of using one metric to define control or elimination across all epidemiologic settings. CONCLUSIONSThese data suggest the need to reevaluate progress and treatment strategies in national schistosomiasis control programs more frequently, with local epidemiologic data taken into consideration, in order to determine the treatment effect and appropriate resource allocations and move closer to achieving the global goals. (Funded by the Children's Investment Fund Foundation and others.

Surveillance on schistosomiasis in five provinces of the People’s Republic of China in the post-elimination era

“…The technicians in selected agencies were asked to perform the IHA and MHT tests according to the protocol of each method [12][13][14] and judge the results. The results were documented and reported to NIPD, China CDC within the given time.…”

Fine-scale heterogeneity in Schistosoma mansoni force of infection measured through antibody response

“…3 The World Health Organization has targeted the global elimination of schistosomiasis as a public health goal by 2025, defined as a reduction to <1% prevalence of heavy intensity infections across sentinel sites. 2 A cornerstone of the global control strategy has been delivery of the drug praziquantel to school-age children (5 -15 years) through mass drug administration (MDA) campaigns in endemic regions. 4 School-age children have been a focus of MDA efforts because S. mansoni infection intensity and egg shedding peaks at ages 10 -15 years, 3 and because schools provide a logistically convenient approach for locating children through large-scale programs.…”

Gender Related Differences in Infection Intensity, Prevalence and Risk of Schistosoma Mansoni and Schistosoma Haematobium: A Systematic Review Protocol

“…Over 90% of people requiring treatment for schistosomiasis live in sub Saharan Africa where the major form of control is through preventive chemotherapy with praziquantel [7]. Although, over the last decade, progress has been made in achieving morbidity control in several countries in this region, more remains to be done [8]. The newly drafted World Health Organization (WHO) NTD roadmap for 2021-2030 outlines achieving elimination as a public health problem for schistosomiasis and aims to attain this by extending treatment to all in need [9].…”