Village-scale persistence and elimination of gambiense human African trypanosomiasis

Résumé

Gambiense human African trypanosomiasis (gHAT) is one of several neglected tropical diseases that is targeted for elimination by the World Health Organization.Recent years have seen a substantial decline in the number of globally reported cases, largely driven by an intensive process of screening and treatment.However, this infection is highly focal, continuing to persist at low prevalence even in small populations.Regional elimination, and ultimately global eradication, rests on understanding the dynamics and persistence of this infection at the local population scale.Here we develop a stochastic model of gHAT dynamics, which is underpinned by screening and reporting data from one of the highest gHAT incidence regions, Kwilu Province, in the Democratic Republic of Congo.We use this model to explore the persistence of gHAT in villages of different population sizes and subject to different patterns of screening.Our models demonstrate that infection is expected to persist for long periods even in relatively small isolated populations.We further use the model to assess the risk of recrudescence following local elimination and consider how failing to detect cases during active screening events informs the probability of elimination.These quantitative results provide insights for public health policy in the region, particularly highlighting the difficulties in achieving and measuring the 2030 elimination goal. Author summaryGambiense human African trypanosomiasis (gHAT) is a vector-borne infectious disease that causes sleeping sickness across many African countries.Reported gHAT cases show a continued decline, but it is unclear if this is sufficient to reach the WHO goal of stopping transmission by 2030.We develop a stochastic model necessary to address the critical question of persistence of gHAT infection at the local-scale.In contrast to other commonly studied infections, we predict long-term persistence of gHAT in small populations (< 1, 000 people) despite very low prevalence.Our local-scale predictions (together with previous larger-scale studies) suggest that, to achieve regional elimination, controls need

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