Human African trypanosomiasis

Eliminating sleeping sickness as a public health problem is on track


14 June 2017 | Geneva −− The latest data released by the World Health Organization (WHO) show a sustained decrease in the number of new cases of human African trypanosomiasis (also known as sleeping sickness) indicating that its elimination as a public health problem is within reach.

The training in data analysis and management aims to strengthen and sustain local capacity particularly for geospatial data – starting with the Democratic Republic of the Congo.

We’ve received reports of 2184 new cases in 2016,” said Dr José Ramón Franco, Medical Officer, WHO Department of Control of Neglected Tropical Diseases. “It represents the lowest number of sleeping sickness cases ever recorded and demonstrates that we’re well on track to achieving elimination as a public health problem by 2020.”

In 2012, WHO set a global elimination target to achieve “fewer than 2000 reported cases per year” by 2020. But thanks to uninterrupted control activities, improved surveillance and reinforced passive case-finding since 2014, the annual milestones have been surpassed.

This progress results from the sustained efforts of national control programmes with the support of different partners,” said Dr Gerardo Priotto, Medical Officer, WHO Department of Control of Neglected Tropical Diseases. “With reduced numbers of cases, we’ll need to progressively shift away from active screening of people to combined passive surveillance and reactive screening, and this can be one of the main challenges to elimination”.

Other challenges include the need to sustain the commitment of all stakeholders, increase ownership of elimination programmes by endemic countries, integrate control activities into weak national health systems and ensure the funding necessary to achieve the elimination target.

Strengthened control and surveillance over the past 15 years have progressively reduced transmission of the disease – from below 10 000 cases in 2009 to fewer than 5000 in 2014 and reaching a historic low of 2184 cases in 2016.

In the last ten years, over 75% of reported cases occurred in the Democratic Republic of the Congo (DRC). The DRC is the only country that currently reports more than 1000 new cases annually and accounts for 81% of the cases reported in 2015.

In 2014 a coordination network for elimination of the disease was established under WHO leadership. It includes stakeholders such as national sleeping sickness control programmes, groups developing new tools, international and nongovernmental organizations involved in disease control, and donors.

Collaboration

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 with Trypanosoma 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

WHO/HTM/NTD
Telephone: +41 22 791 1637
Mobile phone: +41 79 540 50 86
molooa@who.int