Personal View A call to strengthen the global strategy against schistosomiasis and soil-transmitted helminthiasis: the time is now Nathan C Lo, David G Addiss, Peter J Hotez, Charles H King, J Russell Stothard, Darin S Evans, Daniel G Colley, William Lin, Jean T Coulibaly, Amaya L Bustinduy, Giovanna Raso, Eran Bendavid, Isaac I Bogoch, Alan Fenwick, Lorenzo Savioli, David Molyneux, Jürg Utzinger, Jason R Andrews Lancet Infect Dis 2016 In 2001, the World Health Assembly (WHA) passed the landmark WHA 54.19 resolution for global scale-up of mass Published Online administration of anthelmintic drugs for morbidity control of schistosomiasis and soil-transmitted helminthiasis, which November 29, 2016 affect more than 1·5 billion of the world’s poorest people. Since then, more than a decade of research and experience has http://dx.doi.org/10.1016/ S1473-3099(16)30535-7 yielded crucial knowledge on the control and elimination of these helminthiases. However, the global strategy has Division of Infectious Diseases remained largely unchanged since the original 2001 WHA resolution and associated WHO guidelines on preventive and Geographic Medicine chemotherapy. In this Personal View, we highlight recent advances that, taken together, support a call to revise the global (N C Lo BS, J R Andrews MD), strategy and guidelines for preventive chemotherapy and complementary interventions against schistosomiasis and soil- and Division of Epidemiology, transmitted helminthiasis. These advances include the development of guidance that is specific to goals of morbidity Stanford University School of Medicine, Stanford, CA, USA control and elimination of transmission. We quantify the result of forgoing this opportunity by computing the yearly (N C Lo); Children Without disease burden, mortality, and lost economic productivity associated with maintaining the status quo. Without change, Worms, Task Force for Global we estimate that the population of sub-Saharan Africa will probably lose 2·3 million disability-adjusted life-years and Health, Decatur, GA, USA US$3·5 billion of economic productivity every year, which is comparable to recent acute epidemics, including the (D G Addiss MD); Sabin Vaccine Institute and Texas Children’s 2014 Ebola and 2015 Zika epidemics. We propose that the time is now to strengthen the global strategy to address the Hospital Center for Vaccine substantial disease burden of schistosomiasis and soil-transmitted helminthiasis. Development, National School of Tropical Medicine at Baylor Introduction people using praziquantel (against schistosomiasis) and College of Medicine, Houston, TX, USA (Prof P J Hotez MD); More than 15 years ago, the World Health Assembly 565 million people using albendazole or mebendazole Department of Biology, Baylor (WHA) passed the landmark WHA 54.19 resolution to (against soil-transmitted helminthiasis) throughout Africa, University, Waco, TX, USA address the 1·5 billion people affected by schistosomiasis Asia, Latin America, and the Middle East.5,6 During this (Prof P J Hotez); James A Baker and soil-transmitted helminthiasis (including ascariasis, period, the number of infections and global disease burden III Institute for Public Policy, Rice University, Houston, TX, 1,2 1,2,7 hookworm disease, and trichuriasis). WHO sub- estimates have been correspondingly reduced. This USA (Prof P J Hotez); Center for sequently created a Department of Neglected Tropical strategy of morbidity control has defined a goal of Global Health and Diseases, Diseases (NTDs), and produced guidelines that set a new eliminating helminths as a public health problem. For soil- Case Western Reserve framework for a public health approach against many transmitted helminthiasis, this goal is defined as less than University, Cleveland, OH, USA (Prof C H King MD); NTDs, including schistosomiasis and soil-transmitted 1% prevalence of moderate-to-heavy intensity infection in Department of Parasitology, helminthiasis, through a strategy of preventive chemo- at-risk populations, as determined by egg counts on Liverpool School of Tropical therapy (via mass drug admin istration).3 This strategy microscopic examination; for schistosomiasis, the goal has Medicine, Liverpool, UK involves large-scale, periodic (eg, yearly) empirical been expressed as less than 1% prevalence of heavy- (Prof J R Stothard PhD, Prof D Molyneux DSc); treatment of entire populations and typically focuses on intensity infections based on egg counts in stools or urine. United States Agency for groups assumed to have the greatest disease morbidity, Although this commendable morbidity control International Development, such as school-aged children (aged 5–15 years) for strategy has certainly led to success, mainly by averting Global Health, Washington, DC, USA (D S Evans DPH); schistosomiasis and preschool and school-aged children long-term sequelae in school-aged children, the Center for Tropical and 3,4 8,9 (aged 1–15 years) for soil-transmitted helminthiasis. reinfection rate has been high in most settings. Emerging Global Diseases and These helminthiases are characterised by mostly chronic, Unfortunately, even countries that have successfully the Department of often insidious helminth-specific sequelae ranging from implemented the recommended preventive chemo- Microbiology, University of Georgia, Athens, GA, USA mild to severe morbidities. These sequelae include therapy strategy for schistosomiasis and soil-transmitted (Prof D G Colley PhD); Global anaemia, chronic abdominal pain, and malnutrition, and helminthiasis—ie, WHO recommends repeated Public Health, Johnson & also more rare and serious complications including treatment of school-aged children with at least Johnson, New Brunswick, NJ, bladder cancer, hepato splenomegaly, and death for 75% coverage—have met challenges in achieving USA (W Lin PhD); Unité de Formation et de Recherche schistosomiasis, and small bowel obstruction and rectal optimal morbidity control or the more ambitious goal of Biosciences, Université Félix 8,10,11 prolapse for soil-transmitted helminthiasis. transmission elimination. This finding is consistent Houphouët-Boigny, Abidjan, Today, under the auspices of the WHO Department of with estimates by the Global Burden of Disease (GBD) Côte d’Ivoire NTDs—catalysed by the 2012 London Declaration for study12 and others5 that have documented how progress (J T Coulibaly PhD); Centre Suisse de Recherches NTDs, and with large-scale support from governments, has lagged behind for schistosomiasis and soil- Scientifiques en Côte d’Ivoire, pharmaceutical companies, and non-governmental transmitted helminthiasis relative to many other NTDs. Abidjan, Côte d’Ivoire organisations (NGOs)—preventive chemotherapy pro- To address this challenge, in light of the past decade (J T Coulibaly); Swiss Tropical grammes have achieved impressive gains. In 2015 alone, of data and experience from the field, we re-visit and Public Health Institute, Basel, Switzerland these programmes delivered treatment to 65 million the global strategy for preventive chemotherapy and www.thelancet.com/infection Published online November 29, 2016 http://dx.doi.org/10.1016/S1473-3099(16)30535-7 1 Personal View studies.16 Furthermore, expanded community-wide Strength of evidence treatment can be highly cost-effective because of this Step 1: Update strategy for preventive chemotherapy averted morbidity, even if transmission is not Expanded treatment across broader age groups Modelling and cost-effectiveness studies,10,13–15 with eliminated.10,14 To achieve community-wide coverage, (ie, community-wide treatment) support from systematic review and meta-analysis of settings could use distribution networks from other observational studies16 community-based health platforms for feasibility and 14 Lower prevalence thresholds for treatment, Modelling and cost-effectiveness studies, with cost-efficiency, including integration with vaccination especially for schistosomiasis support from observational studies programmes, Demographic and Health Surveys (DHS), Formal guidelines for integration of praziquantel Cost-effectiveness modelling studies, with support and benzimidazole programming from feasibility studies10,14,17,18 or through continued use of lymphatic filariasis or onchocerciasis drug distributors who have delivered Validated strategy with trial data Trials underway community-wide anthelmintics (eg, ivermectin and 19 Rigorous monitoring and evaluation strategies to Statistical models with field validation 33,34 detect emergence of drug resistance albendazole) at scale. Guidelines currently provide prevalence thresholds, Step 2: Incorporate complementary interventions in the global strategy above which a preventive chemotherapy strategy is Water, sanitation, and hygiene programming Systematic review and meta-analysis with mixed (eg, community-led total sanitation) findings, including mostly observational studies20–28 recommended, but these guidelines might be too restrictive to achieve optimal averted disability and cost- Information, education, and communication Trial data26 14 programmes effectiveness even under a goal of morbidity control. Snail control (for Schistosoma spp) Systematic review and meta-analysis, including These prevalence thresholds are based on expert opinion mostly observational studies; modelling studies29,30 and a historically more limited drug supply, and have 3,4 Step 3: Create distinct guidelines based on epidemiology, programmatic goals, and resource constraints remained largely unchanged for more than a decade.