The Human African Trypanosomiasis Control and Surveillance Programme of the World Health Organization 2000–2009: The Way Forward

Abstract

One century ago human African trypanosomiasis (HAT), also known as sleeping sickness, was believed to curb the development of colonial territories. As soon as the cause of the disease was clearly identified, colonial authorities established extensive control operations, fearing an unpopulated continent and a shortage of human labour to exploit natural resources. Systematic screening, treatment, and patient follow-up was established in western and central Africa for the gambiense form of the disease while, animal reservoir and vector control was mainly implemented in eastern and southern Africa for the rhodesiense form. By the 1960s, transmission was practically interrupted in all endemic areas, providing evidence that the elimination of the disease as a public health problem was feasible and could be achieved with basic tools. Thereafter, the rarity of cases led to a loss of interest in sustained surveillance, and the risk of re-emergence of the disease was overlooked. Thus in the 1980s the disease re-emerged. By the 1990s, flareups were observed throughout past endemic areas, leading to a worrisome increase in the number of reported cases. At this time, nongovernmental organizations (NGOs) played a crucial role in the control of HAT. However, their interventions were mainly focused on remote and insecure areas. As emergency operators, their policy understandably excluded support to National Sleeping Sickness Control Programmes (NSSCPs), which resulted in (i) the establishment of substitute HAT control systems (ii), the maintenance of a large part of the population at risk out of the umbrella of NGO projects, and (iii) the difficulty for national programmes to sustain control achievements after the NGOs’ withdrawal. Concurrently, bilateral cooperation continued to support NSSCPs in some historically linked countries. Concerning HAT screening, the card agglutination trypanosomiasis test (CATT) for serological screening of populations at risk of HAT gambiense was developed during the 1970s [1], but its large-scale production encountered many problems, hindering its availability [2]; in addition, production of anti-trypanosomal drugs was seriously threatened due to the lower economic return for manufacturers. Research for new diagnostic tools and drugs was scarce [3]. Only eflornithine, initially developed for cancer treatment, was finally registered for the treatment of the gambiense form of the disease in 1990 [4]. But its cost and complex distribution and administration requirements made it inappropriate for the under-equipped peripheral health services in remote rural areas where HAT was prevalent. Only some well-funded NGOs were able to afford the cost of eflornithine treatment. During the 1990s, security constraints due to civil wars and social upheavals complicated HAT control by preventing access to a large number of HAT-endemic areas, leading to difficulties in reaching a large number of affected populations and consequently to a considerable lack of epidemiological information. The World Health Organization (WHO) Expert Committee on HAT Control and Surveillance held in 1995, in consideration of the huge uncertainties between the reported cases and the factual field situation, estimated that the true number of cases was at least 10 times more than reported. Thus from the 30,000 reported cases annually, it was estimated that some 300,000 infected individuals remained ignored in the field [5]. In 1997, the 50th World Health Assembly expressed its concerns about the major recrudescence of cases by adopting a resolution to raise awareness and national and international interest [6]. Subsequently, WHO enhanced its coordinating role and promoted networking with partners, developing a strong advocacy and awareness campaign. As a result, the private sector recognized its responsibility, which led Aventis Pharma and Bayer Health Care to grant in 2001 and 2002 a substantial support to WHO for the control and surveillance of HAT. This support included HAT drug donation and financial contributions that allowed WHO to strengthen its support to diseaseendemic countries (DECs). The importance of the various components of the epidemiology of trypanosomiasis (human, animal, vector control, agricultural activity, and livestock production) and their impact on the development of rural Africa led WHO, in 1995, to promote together with the Food and Agriculture Organization (FAO), the International Atomic Energy Agency (IAEA), and the African Union InterAfrican Bureau for Animal Resources (AUIBAR), an inter-sectoral initiative that ultimately became, in 1997, the Programme Against African Trypanosomiasis (PAAT, http://www.fao.org/ag/againfo/ programmes/en/paat/disease.html). In parallel, African heads of state and governments established during the Afri-