Tag Archives: tsetse fly

Togo is the first African country to eliminate sleeping sickness

Togo, officially the Togolese Republic (République togolaise), a country in West Africa has received validation from the World Health Organization (WHO) for having eliminated human African trypanosomiasis or “sleeping sickness” as a public health problem, becoming the first country in Africa to reach this milestone. It gets its nickname ‘sleeping sickness’ because symptoms can include a disturbed sleep pattern.  

What is African sleeping sickness?

Sleeping sickness is caused by parasites that are transmitted by infected tsetse flies and is only found in 36 countries in sub-Saharan Africa. If left untreated sleeping sickness is almost always fatal. In 1995, about 300,000 cases were estimated to have gone undetected, with 60 million people estimated to be at risk of infection. In 2019, fewer than 1,000 cases were found.

Illustration of the life cycle of the trypanosome parasite that causes African sleeping sickness.
Image credit: Genome Research Limited

What are the two forms of sleeping sickness?

There are two forms of sleeping sickness. The first, due to Trypanosoma brucei gambiense, is found in 24 countries in west and central Africa and accounts for more than 98% of cases. The second form, due to Trypanosoma brucei rhodesiense, is found in 13 countries in eastern and southern Africa and represents the rest of cases. WHO and partners are targeting the elimination as a public health problem of the gambiense form of the disease from all endemic countries by 2030. Benin, Burkina Faso, Cameroon, Cote d’Ivoire and Ghana have started the validation process with the support of WHO.

How did Togo eliminate African sleeping sickness?

Togo has not reported any cases in the past 10 years. Togo’s achievement comes after more than two decades of sustained political commitment, surveillance and screening of cases. Beginning in 2000, the country’s public health officials implemented control measures. In 2011, the country established surveillance sites at hospitals in the cities of Mango and Tchamba, which cover the main areas at risk of the disease. Public health officials have since maintained heightened disease surveillance in endemic and at-risk areas. Neighboring countries are not at the same phase and so surveillance must continue to avoid a resurgence of this disease.

Togo first applied for certification of elimination of sleeping sickness in 2018 and a team of WHO experts studied the data, made recommendations and requested a revision by the country before giving their approval. A WHO-led global collaboration supported these efforts by facilitating the donation of medicines and resources from pharmaceutical companies, which helped strengthen local capacity and ensure the sustained availability of tools required to control the disease. Wiping out the gambiense form of sleeping sickness will require maintaining the commitment of endemic countries and of donors, as well as integrating control and surveillance activities into the regular health systems.

A disease you might not have heard of is on track for elimination

Human African trypanosomiasis (HAT), also known as sleeping sickness, is a parasitic disease that attacks the central nervous system, causing severe neurological disorders and death if left untreated. It is transmitted by the bite of the ‘Glossina’ insect, commonly known as the tsetse fly.

The disease mostly affects poor populations in rural areas where agriculture, fishing, animal husbandry, or hunting are the main source of livelihood. Typically, HAT is not found in urban areas, although cases have been reported in suburban areas of big cities in 36 sub-Saharan African countries where the disease is endemic. Travelers also risk becoming infected if they go to regions where the insect is common.

HAT wreaked havoc in Africa at different times in the 20th century but over the past twenty years, huge efforts made by a broad coalition of stakeholders, curbed the last epidemic.

Human African trypanosomiasis takes two forms, depending on the parasite involved: Trypanosoma brucei gambiense, found in 24 countries in west and central Africa, accounts for 98% of reported cases of sleeping sickness and causes a chronic infection.

A person can be infected for months or even years without major signs or symptoms of the disease. When more evident symptoms emerge, the patient is often already in an advanced disease stage.

Trypanosoma brucei rhodesiense is found in 13 countries in eastern and southern Africa. This form represents under 2% of reported cases and causes an acute infection that invades the central nervous system.

A detailed analysis of data systematically collected by WHO in the years 2000-2018 in the HAT Atlas was published in PLoS NTDs showing the updated picture of the elimination trends in this disease. The analysis of global indicators and milestones of the WHO NTD roadmap has been updated to 2018 and recently published. The disease occurrence, the geographical distribution and the control activities show that:

  • 977 cases of HAT were reported in 2018, down from 2,164 in 2016.
  • The area at moderate or high risk of HAT has shrunk to less than 200,000 square kilometres. More than half of this area is in the Democratic Republic of the Congo. In the last 10 years, over 70% of reported cases occurred in the Democratic Republic of the Congo.
  • Health facilities providing diagnosis and treatment for HAT have increased since the last survey, meanwhile active screening is maintained at similar levels.

The number of cases, the main global indicator, is already well within the 2020 target (i.e. 2,000 cases). The areas at moderate or higher risk (i.e. > 1 case/10,000 people/year) are also nearing the 2020 target. The reliability of these data is backed by a reinforced coverage of the populations at risk by surveillance and control activities, providing strong evidence that global elimination of the disease is advancing.

There is no vaccine or drug for prophylaxis and preventive measures are aimed at minimizing contact with tsetse flies. Sleeping sickness is curable with medication but is fatal if left untreated. Surveillance networks, such as ProMED-mail and TropNetEurop should be maintained and expanded to ensure access to institutional databases. Due to the success of surveillance systems in Western countries, the possibility of introducing similar ‘alarm’ systems for HAT in Africa should be explored. Innovation in HAT control and surveillance is still needed but the 2030 goal of elimination as interruption of HAT transmission is on track.