Preventive Chemotherapy Versus Innovative and Intensified Disease Management in Neglected Tropical Diseases: A Distinction Whose Shelf Life Has Expired

Dr. Julio Frenk, the former dean of the Harvard School of Public Health, has said (in a personal communication) that “The greatest threat to global health is dichotomous thinking, thinking that things are either black or white, all good or all bad.” This sort of thinking is simplistic and often prevents us from seeing how to best solve our most serious problems, pitting advocates against each other and blinding different stakeholders to innovations and solutions that involve collaboration, dialogue, and compromise. The term “neglected tropical diseases” (NTDs) came into use some ten years ago to refer to a group of diseases that occur most commonly in the tropics and subtropics [1,2]. Although NTDs cause considerable morbidity and human suffering, progress in controlling them remained limited, in large part because they affect marginalized and impoverished populations. The NTD label provided a greater profile, facilitated advocacy, and, especially in the last couple of years, caught the attention of policy makers, philanthropists, and donors [3]. For a number of years, we have used a distinction between those NTDs whose treatment and prevention involve mass drug administration (MDA) and those which involve individual case finding and case management. We have labeled the former the “preventive chemotherapy and transmission control” (PCT) NTDs and the latter the “innovative and intensified disease management” (IDM) NTDs. The Department of Control of Neglected Tropical Diseases of the World Health Organization (WHO), for example, uses this distinction and accordingly has classified some diseases as “IDM” and others as “PCT” (see: http://www.who.int/neglected_ diseases). Most people working in the NTD field have accepted and adhere to this distinction. PCT focuses on those NTDs for which a global strategy exists and for which tools are readily available for large-scale deployment [4]. The most prominent examples of NTDs that have been allocated to the PCT group are lymphatic filariasis, onchocerciasis, schistosomiasis, and soiltransmitted helminthiasis; the main tool for their control is the periodic administration of efficacious, safe, and inexpensive (usually donated) drugs to entire at-risk populations without prior individual diagnosis [1,2,5,6]. IDM, on the other hand, focuses on those NTDs that currently lack appropriate tools for large-scale use. Hence, in general, the IDMNTDs are currently more difficult and costly to manage than some of the PCT diseases, as there are inherent challenges for their diagnosis, treatment, and follow-up. Buruli ulcer [7], Chagas disease [8], human African trypanosomiasis [9], and leishmaniasis [10] are examples of IDMNTDs. The separation of NTDs into mutually exclusive groups has been further cemented by referral to “toolready” and “tool-deficient” diseases—a terminology used byWHO [4] and the Centers for