Human African trypanosomiasis

Progress on eliminating sleeping sickness as a public health problem

5 December 2018 | Geneva – The latest data released by the World Health Organization (WHO) confirms the sustained decrease in the number of new cases of human African trypanosomiasis (also known as sleeping sickness). A disease that in the 20th century caused devastating epidemics is becoming a rare disease today. The sustained efforts against HAT of National Control programmes, supported by WHO and a range of committed stakeholders and maintained over the last twenty years enabled dramatically reduction of the prevalence, and the disease is now on track for the WHO elimination goal.

With 1,442 reported cases in 2017 the 2020 target of elimination as a public health problem is being attained. The coverage of at risk populations by surveillance activities has also improved giving more robustness to the figure. However, looking beyond 2020, achieving the sustainable elimination of transmission (zero cases) for the gambiense form of the disease (targeted for 2030), there is no room for complacency. This challenge will require the sustained commitment of HAT endemic countries and donors, the effective integration of HAT control activities in the health system, the development of improved tools, the adoption of innovative disease control approaches, and the coordination of a broad range of stakeholders to ensure synergy of efforts.

Considering the epidemiological situation by country, the elimination of HAT as public health problem could be considered as already achieved in a number of HAT endemic countries. The criteria to assess and validate this status have been developed by WHO to enable the claim by countries and the formal recognition by WHO. It is expected that request of validation of the elimination in some countries will be submitted in the next year.


In the early 2000s and through an exemplary WHO public–private partnership with Sanofi and Bayer HealthCare, a WHO-led control and surveillance programme was launched to strengthen support to endemic countries for control activities and ensure wider access to treatment available free of charge. WHO ensures the distribution of the donated anti-trypanosomal medicines to endemic countries through this partnership with Sanofi (for pentamidine, melarsoprol and eflornithine) and with Bayer HealthCare (for suramin and nifurtimox).

The disease

Human African trypanosomiasis, or sleeping sickness, 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.

The two main forms of human African trypanosomiasis result from infection withTrypanosoma brucei gambiense (accounting for more than 98% of all reported cases) and Trypanosoma brucei rhodesiense.

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.

The efforts of WHO, national sleeping sickness control programmes, bilateral cooperation and nongovernmental organizations during the 1990s and the first decade of this century have reversed this trend.

Ashok Moloo
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