Proud Roland, Allan Fiona, Whiston Andrew, Kayanda Robert, Kinung'hi Safari, Angelo Teckla, Sylivester Yasinta D, Mrosso Hillary D J, Kashindye Benedicto B, Elison Mboni, Cox Martin J, Yang Yang, Chamberlin Andrew, Boyd Ian L, Civitello David J, De Leo Giulio A, Brierley Andrew S
Pelagic Ecology Research Group, School of Biology, Gatty Marine Laboratory, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, United Kingdom.
Cupar Analytics Ltd, Cupar, United Kingdom.
PLoS Negl Trop Dis. 2025 Sep 3;19(9):e0013490. doi: 10.1371/journal.pntd.0013490. eCollection 2025 Sep.
In areas of high infection prevalence, effective control of schistosomiasis - one of the most important Neglected Tropical Diseases - requires supplementing medical treatment with interventions targeted at the environmental reservoir of disease. In addition to provision of clean water, reliable sanitation, and molluscicide use to control the obligate intermediate host snail, top-down biological control of parasite-competent snails has recently gained increasing interest in the scientific community. However, evidence that natural predators can effectively reduce snail abundance and, ultimately, transmission risk to vulnerable human populations remains limited. In this study, we used a Before-After-Control-Intervention (BACI) design implemented in seven lakeside areas, including three intervention areas and four control areas, on the southern shores of Lake Victoria (Tanzania) in 2019-2023. We tested whether the restoration of African catfish, Clarias gariepinus, a native species of commercial value, could reduce both the abundance of Biomphalaria snails (intermediate hosts of Schistosoma mansoni) and infection intensity in school age children (SAC). Where catfish were restored, mean site-level snail counts declined by 57% (95% CI: 29.4%, 74.3%). At primary schools located within each area, SAC infection intensity (mean parasite egg count in stool samples) also decreased significantly by 55% (95% CI: 26%, 73%). This study shows that natural predators of host snails have the potential for schistosomiasis control. Scaling up to a lake-wide approach will require systemic intervention, with snail host control contributing to a broader framework for schistosomiasis management.
在感染率高的地区，有效控制血吸虫病（最重要的被忽视热带病之一）需要在药物治疗的基础上，辅以针对疾病环境宿主的干预措施。除了提供清洁水、可靠的卫生设施以及使用杀螺剂来控制 obligate 中间宿主蜗牛外，对有感染能力的蜗牛进行自上而下的生物控制最近在科学界越来越受到关注。然而，关于天然捕食者能够有效减少蜗牛数量并最终降低对易感人群传播风险的证据仍然有限。在本研究中，我们于 2019 年至 2023 年在维多利亚湖（坦桑尼亚）南岸的七个湖滨地区采用了前后对照干预（BACI）设计，其中包括三个干预区和四个对照区。我们测试了恢复具有商业价值的本地物种非洲鲶鱼（Clarias gariepinus）是否能减少曼氏血吸虫中间宿主双脐螺（Biomphalaria 蜗牛）的数量以及学龄儿童（SAC）的感染强度。在恢复了鲶鱼的地方，平均现场蜗牛数量下降了 57%（95%置信区间：29.4%，74.3%）。在每个区域内的小学，学龄儿童的感染强度（粪便样本中的平均寄生虫卵数）也显著下降了 55%（95%置信区间：26%，73%）。这项研究表明，宿主蜗牛的天然捕食者具有控制血吸虫病的潜力。扩大到全湖范围的方法将需要系统性干预，蜗牛宿主控制将有助于形成更广泛的血吸虫病管理框架。
