부산대학교 도서관

Background: Gambian human African trypanosomiasis (gHAT) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by tsetse flies (Glossina). In Côte d'Ivoire, Bonon is the most important focus of gHAT, with 325 cases diagnosed from 2000 to 2015 and efforts against gHAT have relied largely on mass screening and treatment of human cases. We assessed whether the addition of tsetse control by deploying Tiny Targets offers benefit to sole reliance on the screen-and-treat strategy. Methodology and principal findings: In 2015, we performed a census of the human population of the Bonon focus, followed by an exhaustive entomological survey at 278 sites. After a public sensitization campaign, ~2000 Tiny Targets were deployed across an area of 130 km2 in February of 2016, deployment was repeated annually in the same month of 2017 and 2018. The intervention's impact on tsetse was evaluated using a network of 30 traps which were operated for 48 hours at three-month intervals from March 2016 to December 2018. A second comprehensive entomological survey was performed in December 2018 with traps deployed at 274 of the sites used in 2015. Sub-samples of tsetse were dissected and examined microscopically for presence of trypanosomes. The census recorded 26,697 inhabitants residing in 331 settlements. Prior to the deployment of targets, the mean catch of tsetse from the 30 monitoring traps was 12.75 tsetse/trap (5.047–32.203, 95%CI), i.e. 6.4 tsetse/trap/day. Following the deployment of Tiny Targets, mean catches ranged between 0.06 (0.016–0.260, 95%CI) and 0.55 (0.166–1.794, 95%CI) tsetse/trap, i.e. 0.03–0.28 tsetse/trap/day. During the final extensive survey performed in December 2018, 52 tsetse were caught compared to 1,909 in 2015, with 11.6% (5/43) and 23.1% (101/437) infected with Trypanosoma respectively. Conclusions: The annual deployment of Tiny Targets in the gHAT focus of Bonon reduced the density of Glossina palpalis palpalis by >95%. Tiny Targets offer a powerful addition to current strategies towards eliminating gHAT from Côte d'Ivoire. Author summary: Gambian sleeping sickness (Gambian human African trypanosomiasis, gHAT) is a neglected tropical disease caused by Trypanosoma brucei gambiense transmitted by tsetse flies. Currently, Bonon is the focus which provides most cases of gHAT in Côte d'Ivoire. Screening and treatment of human cases has reduced the incidence of gHAT from 262 cases diagnosed between 2000 and 2004 to 24 cases during 2010–2015. We carried out a trial to assess whether Tiny Targets, insecticide-treated targets that attract and kill tsetse, could control Glossina palpalis palpalis, the most important vector of gHAT in Côte d'Ivoire. In 2015, we mapped human settlements, livestock, tracks, rivers and relict forest in Bonon and identified sites where humans may be bitten by tsetse. Monoconical ("Vavoua") traps were deployed at these sites to provide an estimate of the abundance of tsetse. Between 2016 and 2018, ~2,000 Tiny Targets were deployed annually across Bonon and the impact of Tiny Targets was evaluated by changes in the numbers of tsetse caught by a network of 30 monitoring traps operated quarterly. In 2015, before deployment of Tiny Targets, the mean daily catch from the 30 monitoring traps was 6.4 tsetse/trap/day. Following deployment of targets, catches declined to <0.3 tsetse/trap/day representing a >95% reduction in tsetse abundance. Between February 2016 and December 2018, no recent (Stage 1) cases of gHAT have been reported in Bonon. Our results demonstrate that Tiny Targets can contribute to the elimination of gHAT through tsetse control. Tiny Targets have been adopted as an important tool in Côte d'Ivoire's national strategy to eliminate gHAT. [ABSTRACT FROM AUTHOR]