Neglected tropical diseases

One year on and accelerating work to overcome neglected tropical diseases


Control of neglected tropical diseases today relies on two pillars: access to treatment with safe and effective medicines available free of charge to affected populations, and a judicious use of pesticides for vector control. Although prospects for scaling-up interventions look promising, there are challenges that remain.

Many countries where soil-transmitted helminthiases are endemic have not attained the target set for 2010 by World Health Assembly resolution WHA54.19, and adopted in 2001, to treat at least 75% of school-aged children at risk of morbidity. In 2009, only 31% of all children at risk of soil-transmitted helminthiases received preventive chemotherapy treatment. But now, with a projected greater availability of funding and donated medicines, WHO plans to scale up integrated preventive treatment of soil-transmitted helminthiases and schistosomiasis to reach a minimum of 75% coverage of all children by 2020.

WHO estimates that US$ 1.7 billion may be needed over the next 5 years to treat all populations at risk of contracting one of the following neglected tropical diseases: lymphatic filariasis, onchocerciasis, soil-transmitted helminthiases (ascariasis, hookworm infections and trichuriasis), schistosomiasis and trachoma. Supplies of donated medicines such as praziquantel and funds for its production are currently insufficient to meet demand for the control of schistosomiasis, which affects more than 240 million people worldwide.

Two billion tablets might be required over the next 5 years. This means that the amount of donated praziquantel needs to increase at least 10–20 times to increase coverage in Africa at a level similar to that of other donated medicines. Today, praziquantel is the only commercially available treatment for human schistosomiasis. It is currently off patent, and most of the active pharmaceutical ingredient is produced in China.

There is also a need for additional treatment facilities to be made available for complex diseases. This will require health-care systems to provide wider access to available medicines and increase capacity for surgical interventions. Success in controlling visceral leishmaniasis involves an increase in capacity for early case-finding and timely delivery of oral treatment.

With cases of human African trypanosomiasis at their lowest level in 50 years, there is need now more than ever to maintain sustained control and surveillance activities using the best, albeit imperfect, tools available. We have to ensure that endemic countries integrate surveillance activities in their services while retaining the capacity to react rapidly to the results of surveillance outcomes. Lesson learnt from the past should be heeded: in the 1980s, the disease re-emerged in many regions after decades of successful control activities.

Control of Chagas disease requires the strengthening of the current global epidemiological surveillance to prevent all forms of transmission and detection. Although nifurtimox is provided free of charge through WHO to all endemic countries, securing adequate provision of benznidazole poses a major challenge.

For Buruli ulcer, specific approaches, such as community education and awareness campaigns, need to be developed to encourage early reporting and detection, and enable timely intervention. The introduction in 2006 of combination antibiotic therapy to treat the early stages of the infection has shown promising results.