Progress towards the worldwide elimination of transmission of human African trypanosomiasis (HAT), otherwise known as sleeping sickness, is maintained, after coronavirus disease (COVID-19)-related disruptions threatened the development of control activities.
HAT has two principal forms: gambiense and rhodesiense.
In 2021, the gambiense form was reported in 11 endemic countries, and a total of 750 cases were declared to the World Health Organization (WHO), with verification of a few cases pending. This figure is higher than the data reported in 2020, when 565 cases were declared.
This increase is in all likelihood due to increased case-finding activity, as systems get progressively back to normal after restrictions provoked by the COVID-19 pandemic. Of these cases, 57% were reported in the Democratic Republic of the Congo. It is also worth highlighting the increase in the number of cases reported in Angola. These amount to 23% of the total, and occur in the context of intensified active screening in areas not covered during previous years.
As for the rhodesiense form of HAT, there were 55 reported cases originating in four countries, with almost 90% of cases occurring in Malawi. This overall figure shows a significant decrease with respect to 2020 data, when 98 cases were reported.
The total number of cases, therefore, for both forms of the disease, was 805 in 2021.
Although this is a slight increase on 2020 figures, the general trend continues and cases remain below 1000, the symbolic threshold achieved for the first time in 2018.
That is in stark contrast to the year 2000, when 26 550 confirmed cases were reported to WHO. Sustained efforts by national control programmes since then and an array of committed stakeholders, working under WHO coordination, have led to a sharp reduction in disease incidence.
The elimination of gambiense HAT as a public health problem has already been validated in four endemic countries (Benin, Côte d’Ivoire, Togo and Uganda), and rhodesiense HAT elimination has been validated in one endemic country (Rwanda).
Elimination of transmission of gambiense HAT (zero cases) by 2030 is a key target of WHO’s new NTD road map. Achieving this goal will require the continued commitment of disease‐endemic countries, partners and donors, as well as effective coordination of efforts. The development of improved and innovative tools will help to ensure the sustainability of disease-control approaches.
The longstanding public–private partnership between WHO and anti-HAT medicine manufacturers Sanofi and Bayer HealthCare has been instrumental in achieving important milestones to date and will be ever more so as work continues to achieve the 2030 target.
