19 Avril 2017|
Neglected tropical diseases
Though medically diverse, the neglected tropical diseases form a group because all are strongly associated with poverty, all flourish in impoverished environments, and all thrive best in tropical areas, where they tend to overlap. Most are ancient diseases that have plagued humanity for centuries. They blind, maim, disfigure, and debilitate their victims, causing untold misery that anchors populations in poverty.
Once widely prevalent, many of these diseases gradually disappeared from large parts of the world as economies developed and living conditions and hygiene improved. Today, the neglected tropical diseases have their hotbeds in the places left furthest behind by socioeconomic progress, where substandard housing, lack of access to safe water and sanitation, chronic hunger, filthy environments, and abundant insects and other vectors contribute to their efficient transmission. In the recent past, the need for control has been hidden from the international community as the diseases themselves rarely travel beyond such deeply impoverished settings.
The situation has changed dramatically over the past ten years, making the control of these diseases one of the best rags-to-riches success stories in modern public health. With more than one billion people affected, efforts to control these diseases are a pro-poor initiative on a massive scale – in effect, a frontal assault on a root cause of poverty. Stepped-up control is based on a deliberate decision not to wait for these diseases to gradually disappear as living conditions improve, but to strike aggressively using a population-wide preventive approach.
The appeal of viewing the neglected tropical disease in this way has been compelling for several groups, most notably the pharmaceutical industry. When the first NTD global partners meeting was convened by WHO in 2007, industry was present with commitments to donate large quantities of effective high-quality medicines to suppress common tropical parasitic and bacterial infections. That commitment opened the way for mass drug administration to at-risk populations with the goal of reducing the human reservoir of parasites and pathogens, eventually resulting in the interruption of transmission.
With large quantities of safe, effective, and free drugs on offer, the goal of immediately expanding access emerged as a moral imperative. It also threw down the gauntlet: if the world cannot deliver high-quality free drugs to those in desperate need, how will it manage to solve much more complex problems?
Several overarching principles and assumptions underpinned the design and implementation of control programmes. First, as the people in greatest need are the poorest of the poor, interventions – no matter how low the price – are unaffordable and must be made available free-of-charge. Drug donations are the only option.
Second, as most at-risk people live beyond the reach of effective health systems, interventions must be simple, safe enough to be administered by non-health staff, and undemanding, ideally requiring only once-yearly contact with the health services.
Third, diseases that are concentrated in very poor populations carry few market incentives for R&D. Many treatments are old and some have toxic side-effects that can be deadly. The job here is to move forward fast with what already exists while clamouring for better products, using field experience to define the ideal product profile, right down to the price.
Finally, ignorance is the first battle that must be fought in the war against extreme poverty. As these diseases are so deeply dreaded by affected populations, community engagement has huge potential to generate grassroots demand for treatment and reduce the stigma that so often rips away social opportunities, especially for women.
Many of these treatments produce tangible results that communities can readily understand. A person who takes a pill and then expels large numbers of worms provides highly visual evidence of cause and effect. Watching the crippling, stigmatizing signs of leprosy disappear in a community or seeing ugly skin conditions and bloody urine vanish provides powerful proof that physical pain, deformities, and emotional misery are not the inevitable companions of poverty. Instead, they can be deliberately and definitively ended. Hope is a precious gift for the extremely poor.