Defining the Necessary Next Steps for Effective Control of Helminthic Infections.

Community-based mass treatment with antihelminthic drugs remains one of the most effective ways of controlling and preventing disease caused by chronic parasitic infections such as filariasis, onchocerciasis, schistosomiasis, and intestinal worm infections within highly endemic areas. This approach, sometimes referred to as deworming, involves annual or biannual delivery of broad-spectrum antihelminthics, most often albendazole or mebendazole, praziquantel, and diethylcarbamazine or ivermectin. Public– private partnerships, facilitated by the World Health Organization, have provided substantial quantities of donated drugs to national control programs in Africa, Asia, Oceania, and South and Central America. With assistance of nongovernmental developmental organizations and of governmental programs such as the US Agency for International Development and the United Kingdom’s Department for International Development, the prevalence of helminth infections and of other “neglected tropical diseases” has been systematically mapped across these regions, and national or regional mass treatment programs have been implemented in most high-risk areas. This approach, termed preventive chemotherapy, aims to prophylactically limit the prevalence of helminth-associated diseases by regularly suppressing infection in areas where transmission can remain ongoing [1]. The logic behind mass treatment is that the drugs are each given as a single dose, they can be given together, and they have limited side effects, and because their cost is minimal and field diagnostics are imperfect, broad-based treatment is the most effective means of reaching all infected persons, as compared with clinicbased or individual screen-and-treat strategies. For some parasites (eg, lymphatic filariasis), widespread drug treatment can reduce or eliminate local transmission of infection, but for others, particularly the Schistosoma species and the soil-transmitted helminths hookworm Ascaris and Trichuris, transmission continues despite broad-based therapy, meaning that repeated rounds of treatment are necessary to maintain suppression of infection and disease [2, 3]. This is not the ideal situation in terms of prevention, but pending full implementation of sanitation and good hygiene practices, continuing mass drug administration (MDA) remains the pillar of helminthic disease control. Implementing and maintaining a mass treatment campaign is not simple or easy. Many locations are difficult to reach or are even “beyond the end of the road” [4]. Because of this, it has been found to be highly effective to employ teachers or community health workers to serve as local drug distributors to schools, villages, or other defined administrative locations within an affected area. This approach was pioneered in onchocerciasis (river blindness) control programs in West Africa and has been adapted to lymphatic filariasis (elephantiasis) control, schistosomiasis control, and intestinal worm control. Integration of control campaigns has led to economies of scale and economies of scope that have provided significant savings in terms of costs of delivery for participating programs [5]. That said, MDA program effectiveness depends strongly on the performance of the community drug distributers and the consequent rates of treatment uptake by the target population [2, 3]. In the current issue of Clinical Infectious Diseases, a new research article by Chami et al [6] reports on an important analysis of the factors associated with patient nonparticipation in a long-term ongoing MDA program in Mayuge District in Uganda. Uganda was one of the first nations in sub–Saharan Africa to implement national-level MDA programs for schistosomiasis and intestinal helminth infections (2003), and it has had good initial successes in morbidity control [7]. However, adherence to treatment has been uneven [8], and problem areas persist where transmission remains at high levels and where MDA coverage is incomplete. The analysis of patient participation reported in the Chami et al article has a number of strengths. It identifies individual-level patient characteristics for participation andnonparticipation during Received 9 September 2015; accepted 10 September 2015; published online 25 September 2015. Correspondence: C. H. King, Center for Global Health and Disease, Case Western Reserve University School of Medicine, 2109 Adelbert Rd, Cleveland, OH 44016 ([email protected]). Clinical Infectious Diseases 2016;62(2):208–9 © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail [email protected]. DOI: 10.1093/cid/civ833