A Research Agenda for Helminth Diseases of Humans: Intervention for Control and Elimination

Abstract

Recognising the burden helminth infections impose on human populations, and particularly the poor, major intervention programmes have been launched to control onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, and cysticercosis. The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. A summary of current helminth control initiatives is presented and available tools are described. Most of these programmes are highly dependent on mass drug administration (MDA) of anthelmintic drugs (donated or available at low cost) and require annual or biannual treatment of large numbers of at-risk populations, over prolonged periods of time. The continuation of prolonged MDA with a limited number of anthelmintics greatly increases the probability that drug resistance will develop, which would raise serious problems for continuation of control and the achievement of elimination. Most initiatives have focussed on a single type of helminth infection, but recognition of co-endemicity and polyparasitism is leading to more integration of control. An understanding of the implications of control integration for implementation, treatment coverage, combination of pharmaceuticals, and monitoring is needed. To achieve the goals of morbidity reduction or elimination of infection, novel tools need to be developed, including more efficacious drugs, vaccines, and/or antivectorial agents, new diagnostics for infection and assessment of drug efficacy, and markers for possible anthelmintic resistance. In addition, there is a need for the development of new formulations of some existing anthelmintics (e.g., paediatric formulations). To achieve ultimate elimination of helminth parasites, treatments for the above mentioned helminthiases, and for taeniasis and food-borne trematodiases, will need to be integrated with monitoring, education, sanitation, access to health services, and where appropriate, vector control or reduction of the parasite reservoir in alternative hosts. Based on an analysis of current knowledge gaps and identification of priorities, a research and development agenda for intervention tools considered necessary for control and elimination of human helminthiases is presented, and the challenges to be confronted are discussed.

Sustained Clearance of Mansonella ozzardi Infection after Treatment with Ivermectin in the Brazilian Amazon

“…39 Considering the results from this study, we suggest that mansonelliasis should be included on that agenda. Moreover, the use of ivermectin may also contribute to the treatment of other helminthic diseases that also occur at this region, and its use could be a relevant strategy for public health programs in areas to which more than one disease is co-endemic.…”

Prevention and control ofTaenia soliumtaeniasis/cysticercosis in Peru

“…62,63 Currently, the vaccine requires at least two doses to be effective, and has been tested in addition to oxfendazole with promising results. [64][65][66][67] Other vaccine candidates include a Taenia crassiceps vaccine 68 and DNA immunization.…”

Rapid Re-Infection with Soil-Transmitted Helminths after Triple-Dose Albendazole Treatment of School-Aged Children in Yunnan, People's Republic of China

“…Single-dose albendazole (400 mg) or mebendazole (500 mg) are used in virtually all preventive chemotherapy schemes against soil-transmitted helminthiasis. [12][13][14] Although single-dose albendazole is highly efficacious against A. lumbricoides and reasonably so against hookworm, single-dose mebendazole reliably cures only A. lumbricoides infections but is considerably less efficacious against hookworm. The treatment of T. trichiura with a single dose of either drug results in low cure rates.…”