Background

Over the past 20 years, schistosomiasis control has been scaled up. Preventive chemotherapy with praziquantel is the main intervention. We aimed to assess the effect of preventive chemotherapy on schistosomiasis prevalence in sub-Saharan Africa, comparing 2000–10 with 2011–14 and 2015–19.

Methods

In this spatiotemporal modelling study, we analysed survey data from school-aged children (aged 5–14 years) in 44 countries across sub-Saharan Africa. The data were extracted from the Global Neglected Tropical Diseases database and augmented by 2018 and 2019 survey data obtained from disease control programmes. Bayesian geostatistical models were fitted to Schistosoma haematobium and Schistosoma mansoni survey data. The models included data on climatic predictors obtained from satellites and other open-source environmental databases and socioeconomic predictors obtained from various household surveys. Temporal changes in Schistosoma species prevalence were estimated by a categorical variable with values corresponding to the three time periods (2000–10, 2011–14, and 2015–19) during which preventive chemotherapy interventions were scaled up.

Findings

We identified 781 references with relevant geolocated schistosomiasis survey data for 2000–19. There were 19 166 unique survey locations for S haematobium and 23 861 for S mansoni, of which 77% (14 757 locations for S haematobium and 18 372 locations for S mansoni) corresponded to 2011–19. Schistosomiasis prevalence among school-aged children in sub-Saharan Africa decreased from 23·0% (95% Bayesian credible interval 22·1–24·1) in 2000–10 to 9·6% (9·1–10·2) in 2015–19, an overall reduction of 58·3%. The reduction of S haematobium was 67·9% (64·6–71·1) and that of S mansoni 53·6% (45·2–58·3) when comparing 2000–10 with 2015–19.

Interpretation

Our model-based estimates suggest that schistosomiasis prevalence in sub-Saharan Africa has decreased considerably, most likely explained by the scale-up of preventive chemotherapy. There is a need to consolidate gains in the control of schistosomiasis by means of preventive chemotherapy, coupled with other interventions to interrupt disease transmission.

Funding

European Research Council and WHO.

中文翻译：

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吡喹酮预防性化疗对撒哈拉以南非洲学龄儿童血吸虫病的影响：一项时空模型研究

背景

过去 20 年，血吸虫病防治规模不断扩大。吡喹酮预防性化疗是主要干预措施。我们旨在评估预防性化疗对撒哈拉以南非洲血吸虫病患病率的影响，将 2000-10 年与 2011-14 年和 2015-19 年进行比较。

方法

在这项时空建模研究中，我们分析了撒哈拉以南非洲 44 个国家的学龄儿童（5-14 岁）的调查数据。这些数据是从全球被忽视的热带病数据库中提取的，并通过从疾病控制计划中获得的 2018 年和 2019 年调查数据进行了扩充。贝叶斯地质统计模型适用于血吸虫和曼氏血吸虫调查数据。这些模型包括从卫星和其他开源环境数据库获得的气候预测数据，以及从各种家庭调查获得的社会经济预测数据。血吸虫的时间变化物种流行率通过一个分类变量进行估计，其值对应于三个时间段（2000-10、2011-14 和 2015-19），在此期间，预防性化疗干预措施扩大。

发现

我们用 2000-19 年的相关地理定位血吸虫病调查数据确定了 781 篇参考文献。有 19 166 个独特的血吸虫调查地点和 23 861个S mansoni调查地点，其中 77%（14 757 个S haematobium和 18 372 个S mansoni调查地点）对应于 2011-19 年。撒哈拉以南非洲学龄儿童血吸虫病患病率从 2000-10 年的 23·0%（95% 贝叶斯可信区间 22·1-24·1）下降到 9·6%（9·1-10·2） 2015-19 年，总体减少 58·3%。与 2000-10 年和 2015-19 年相比， S haematobium减少了67·9%（64·6–71·1），S mansoni减少了53·6%（45·2–58·3）。

解释

我们基于模型的估计表明，撒哈拉以南非洲的血吸虫病患病率已大大降低，这很可能是由于预防性化疗的扩大所致。有必要通过预防性化疗以及其他干预措施来阻断疾病传播，从而巩固在控制血吸虫病方面取得的成果。

资金

欧洲研究委员会和世界卫生组织。