How Guinea pushed sleeping sickness below WHO's elimination threshold

Guinea has eliminated gambiense sleeping sickness as a public health problem, a status WHO validated on 18 January 2025 after new cases were driven below one per 10,000 people in endemic areas over 2019–2023 [s1]. A peer-reviewed account published in July 2026 sets out how a country that once counted the disease in the thousands reached that threshold — through years of mass screening and tsetse-fly control, interrupted but not derailed by the West African Ebola epidemic [s1].

Human African trypanosomiasis (HAT), or sleeping sickness, is a parasitic infection transmitted by the bite of tsetse flies and is usually fatal without treatment [s2]. Its chronic, gambiense form — found across 24 countries of west and central Africa and responsible for 92% of reported cases — can smoulder in a person for months or years before the parasite invades the central nervous system, producing the disrupted sleep cycle that gives the disease its name [s2]. Guinea's coastal mangroves are a classic focus: the disease was endemic there through the last century, was largely controlled in the 1960s and 1970s, then resurged along the coast in the 1990s under demographic and economic pressure on the mangrove ecosystem [s1].

The strategy that worked

Guinea established a national control programme in 2002, built around mass medical screening to find and treat cases [s1]. In 2012 the programme added vector control in the East Boffa focus, deploying "tiny targets" — small insecticide-treated screens that attract and kill tsetse flies to cut human–fly contact [s1]. The approach was disrupted between 2013 and 2016, when the Ebola epidemic that tore through Guinea, Sierra Leone and Liberia forced active screening to give way to passive detection [s1]. When screening resumed in 2016–2017, cases had risen again everywhere except East Boffa, where vector control had held — an unplanned natural experiment in favour of attacking the fly as well as the parasite [s1].

Guinea kept the tiny targets deployed through the COVID-19 pandemic and layered on targeted door-to-door screening of high-risk individuals; since 2018 the programme has screened around 30,000 at-risk people a year [s1]. Treatment also modernised: from 2019 to 2023, 30.1% of cases (45 of 147) were treated with fexinidazole, the first all-oral HAT drug, while patients with advanced neurological disease still received the older nifurtimox–eflornithine combination therapy [s1]. Together, the authors write, these measures pushed new-case numbers below the one-per-10,000 elimination threshold in endemic areas across 2019–2023 [s1].

What "elimination" does and does not mean

The scale of the turnaround is easier to grasp against Guinea's history: the country reported over 10,000 HAT cases by 1941, before mid-century control efforts cut that to 865 cases by 1961 [s1]. The disease's resurgence decades later is a reminder that these gains are reversible, which is precisely why the validated status carries a careful name. "Elimination as a public health problem" is a threshold — sustained low incidence — not eradication, and WHO's roadmap for neglected tropical diseases sets a further, harder goal for gambiense HAT: interruption of transmission, meaning zero cases, by 2030 [s2].

That distinction is the point of the Guinea authors' subtitle, "paving the way for zero transmission." Reported gambiense cases across all endemic countries have already fallen to historic lows — under 2,000 in 2017 and under 1,000 in 2018 — bringing the zero-transmission target within conceivable reach for the first time [s2]. But the programme's own account stresses that getting there will require sustained funding and staffing, continued spatial monitoring of every remaining case, and community engagement to keep vector control running in areas where the disease could otherwise quietly return [s1]. Validation, in other words, is a milestone that has to be defended rather than a finish line [s1].

This article is informational and is not medical advice.

Sources

• [s1] Kagbadouno M, et al., "Elimination of gambiense human African trypanosomiasis as a public health problem in Republic of Guinea: Paving the way for zero transmission," PLOS Neglected Tropical Diseases, 1 July 2026. https://doi.org/10.1371/journal.pntd.0014469
• [s2] World Health Organization, "Trypanosomiasis, human African (sleeping sickness)" fact sheet. https://www.who.int/news-room/fact-sheets/detail/trypanosomiasis-human-african-(sleeping-sickness)