Monitoring the elimination of human African trypanosomiasis: Update to 2016.

José R Franco,Pere P Simarro,Abdoulaye Diarra,Weining Zhao,Daniel Argaw,Massimo Paone,Giuliano Cecchi,Lise Grout,Gerardo Priotto,Philippe Büscher

doi:10.1371/journal.pntd.0006890

Abstract

BackgroundHuman African trypanosomiasis (HAT) is a neglected tropical disease targeted for elimination ‘as a public health problem’ by 2020. The indicators to monitor progress towards the target are based on the number of reported cases, the related areas and populations exposed at various levels of risk, and the coverage of surveillance activities. Based on data provided by the National Sleeping Sickness Control Programmes (NSSCP), Non-Governmental Organizations (NGOs) and research institutions—and assembled in the Atlas of HAT—the World Health Organization (WHO) provides here an update to 2016 for these indicators, as well as an analysis of the epidemiological situation.ResultsTrends for the two primary indicators of elimination are on track for the 2020 goal: 2,164 cases of HAT were reported in 2016 (as compared to the milestone of 4,000 cases), and for the period 2012–2016 280,000 km2 are estimated to be at moderate risk or higher (i.e. ≥ 1 case/10,000 people/year), as compared to the milestone of 230,000 km2. These figures correspond to reductions of 92% and 61% as compared to the respective baselines (i.e. 26,550 HAT cases in the year 2000, and 709,000 km2 exposed at various levels of risk for the period 2000–2004). Among the secondary indicators, an overall improvement in the coverage of at risk populations by surveillance activities was observed. Regarding passive surveillance, the number of fixed health facilities providing gambiense HAT diagnosis or treatment expanded, with 1,338 enumerated in endemic countries in 2017 (+52% as compared to the survey completed only sixteen months earlier). Concerning rhodesiense HAT, 124 health facilities currently provide diagnosis or treatment. The broadening of passive surveillance is occurring in a context of fairly stable intensity of active case finding, with between 1.8 million and 2.4 million people screened per year over the period 2012–2016.DiscussionElimination of HAT as a public health problem by 2020 seems within reach, as the epidemiological trends observed in previous years are confirmed in this latest 2016 monitoring update. However, looking beyond 2020, and in particular to the 2030 goal of elimination of transmission as zero cases for the gambiense form of the disease only, there is no room for complacency. Challenges still abound, including ensuring the effective integration of HAT control activities in the health system, sustaining the commitment of donors and HAT endemic countries, and clarifying the extent of the threat posed by cryptic reservoirs (e.g. human asymptomatic carriers and the possible animal reservoirs in gambiense HAT epidemiology). WHO provides through the network for HAT elimination the essential coordination of the wide range of stakeholders to ensure synergy of efforts.

Highlights

Since the beginning of the 21st century, and following the reinforcement of control and surveillance activities against human African trypanosomiasis (HAT), the number of reported cases has been decreasing steadily [1, 2]
Based on data provided by the National Sleeping Sickness Control Programmes (NSSCP), Non-Governmental Organizations (NGOs) and research institutions—and assembled in the Atlas of Human African trypanosomiasis (HAT)—the World Health Organization (WHO) provides here an update to 2016 for these indicators, as well as an analysis of the epidemiological situation
As established by a WHO Expert Committee on control and surveillance of HAT [1], subsequently refined by the WHO HAT elimination Technical Advisory Group (HAT-e-TAG), and endorsed by the WHO Neglected Tropical Diseases Scientific and Technical Advisory Group (NTD-STAG), HAT elimination is to be monitored through two primary indicators: (1) the annual number of reported cases, where the target for the year 2020 is fewer than 2,000 cases [1], and (2) the area at risk reporting 1 case/10,000 people/year, where the target for 2020 is a reduction of 90% as compared to the 2000–2004 baseline [10, 11]

Summary

Introduction

Since the beginning of the 21st century, and following the reinforcement of control and surveillance activities against human African trypanosomiasis (HAT), the number of reported cases has been decreasing steadily [1, 2]. Control activities have been coordinated and implemented by National Sleeping Sickness Control Programmes (NSSCPs) with the support of the World Health Organization (WHO), in the framework of a longstanding public-private partnership with Sanofi and Bayer, and together with bilateral cooperation, non-governmental organizations (NGOs) and other stakeholders. In this context, in 2012 WHO included the goal of eliminating sleeping sickness as public health problem by 2020 in its Neglected Tropical Diseases (NTD) roadmap [3]. Based on data provided by the National Sleeping Sickness Control Programmes (NSSCP), Non-Governmental Organizations (NGOs) and research institutions—and assembled in the Atlas of HAT—the World Health Organization (WHO) provides here an update to 2016 for these indicators, as well as an analysis of the epidemiological situation

Methods

Results

Discussion

Conclusion