WHO outlines criteria to assess elimination of sleeping sickness
18 July 2018 | Geneva – The latest data released by the World Health Organization (WHO) confirm a sustained decrease in the number of new cases of human African trypanosomiasis (HAT, also known as sleeping sickness), firming up projections that the target to eliminate the disease as a public health problem (1) by 2020 is achievable.
Only 1447 new cases were reported to WHO in 2017 compared with 2184 in 2016 and 9875 cases in 2009.
“We have started to develop criteria that can be used to assess claims by countries for having eliminated the disease as a public health problem as well as the process of validation and formal recognition by WHO,” said Dr José Ramón Franco-Minguell, Medical Officer, WHO Department of Control of Neglected Tropical Diseases. “We expect to start receiving requests for validation of elimination from some countries as early as next year.”
Coverage of affected and at-risk populations through surveillance has also improved, and elimination as a public health problem may already have occurred in a number of countries.
However, looking beyond 2020 and aiming to achieve the sustainable elimination of transmission (that is, zero cases) for gambiense HAT (2) (targeted for 2030) leaves no room for complacency.
“Achieving zero cases by 2030 will require the sustained commitment of affected countries, donors and technical and operational partners, and effective integration of control activities into the health system,” said Dr Gerardo Priotto, Medical Officer, WHO Department of Control of Neglected Tropical Diseases. “We also need to ensure the development of improved tools, the implementation of innovative disease control approaches as well as coordination among various stakeholders to ensure the best possible results."
In the early 2000s, and through an exemplary WHO public–private partnership, a WHO-led control and surveillance programme to strengthen support to endemic countries for control activities and to ensure wider access to treatment free of charge.
WHO ensures the distribution of the donated anti-trypanosomal medicines through this partnership with Sanofi (for pentamidine, melarsoprol and eflornithine) and with Bayer HealthCare (for suramin and nifurtimox).
In 2014, WHO coordinated the setting up of a HAT Elimination Network to ensure strengthened and sustained efforts to eliminate the disease. The stakeholders include national sleeping sickness control programmes, groups developing new tools, international and nongovernmental organizations involved in control, industry and donors.
HAT is a vector-borne parasitic disease caused by infection with protozoan parasites belonging to the genus Trypanosoma. The causative parasite is transmitted to humans through the bite of the tsetse fly (Glossina genus) that has acquired infection from humans or animals harbouring the human pathogenic parasites.
Although several epidemics have affected Africa during the past century, by the mid-1960s the disease had been brought under control through intensive control programmes, resulting in fewer than 5000 cases in the whole continent. However, surveillance lapsed thereafter and the disease re-emerged, reaching epidemic proportions in several regions by 1970.
Under WHO’s leadership, national control programmes, bilateral cooperation agencies and nongovernmental organizations have substantially reduced cases of the disease to unprecedented low numbers and raised hopes for its elimination as a public health problem by 2020.