Department of Biological Sciences, Bindura University of Science Education, Bindura, Zimbabwe; Laboratory of Animal Ecology, Global Change and Sustainable Development, KU Leuven, Leuven, Belgium.
Laboratory of Animal Ecology, Global Change and Sustainable Development, KU Leuven, Leuven, Belgium.
Sci Total Environ. 2024 Dec 1;954:176394. doi: 10.1016/j.scitotenv.2024.176394. Epub 2024 Sep 29.
Freshwater snails act as obligate intermediate hosts for trematode parasites that cause trematodiases threatening public and veterinary health, and biodiversity conservation. While interest in snail control for trematodiases has re-emerged, their ecology remains poorly understood. We examined the relationship between ecosystem indicators - such as environmental variables, macroinvertebrates, macrophytes, and land use - and their correlation with snail abundance, diversity, and infection prevalence in 19 man-made ponds in eastern Zimbabwe. In total, 926 freshwater snails from 10 species were collected, with 547 individuals belonging to five schistosome-competent species: Bulinus tropicus, Bulinus truncatus, Bulinus globosus, Bulinus forskalii, and Biomphalaria pfeifferi. The remaining 379 snails comprised Radix natalensis, Gyraulus sp., and the exotic invasive species Melanoides tuberculata, Pseudosuccinea columella, and Physella acuta. Six cercarial types - mammalian schistosomes, avian schistosomes, longifurcate pharyngeates, echinostomes, amphistomes, and xiphidiocercariae - were isolated from 104 out of 926 snails (11.2 %). PCR revealed a significantly higher infection rate, with 70.2 % of snails testing positive for trematodes. Snail taxon diversity and infection rate significantly varied across land use types, with the lowest values observed in the commercial tobacco farm section, highlighting the potential adverse effects of agriculture on biodiversity. Ponds with extensive Lagarosiphon major (oxygen weed) coverage appeared to facilitate the presence and abundance of P. acuta and P. columella. Schistosome-competent snails such as B. truncatus and B. tropicus seemed to favor shallow water depths and more eutrophic sites characterized by high levels of nitrates, phytoplankton biomass, turbidity, and phycocyanin. These ponds were predominantly associated with the emergent macrophyte Cladium mariscus, revealing a potential association with important intermediate snail hosts. In conclusion, our study emphasizes the complex interplay among environmental factors, macrophyte composition, land use, and the abundance, diversity, and infection prevalence of freshwater snails, offering insights into potential strategies for targeted snail control and disease management in man-made waterbodies.
淡水蜗牛是吸虫寄生虫的必需中间宿主，这些寄生虫会导致威胁公共卫生和兽医健康以及生物多样性保护的吸虫病。虽然人们对控制蜗牛以预防吸虫病的兴趣重新出现，但对其生态仍知之甚少。我们研究了生态系统指标（如环境变量、大型无脊椎动物、大型水生植物和土地利用）与蜗牛丰度、多样性和感染流行率之间的关系，共调查了津巴布韦东部 19 个人工池塘。共采集了 10 种 926 只淡水蜗牛，其中 547 只为 5 种有血吸虫能力的物种：Bulinus tropicus、Bulinus truncatus、Bulinus globosus、Bulinus forskalii 和 Biomphalaria pfeifferi。其余 379 只蜗牛由 Radix natalensis、Gyraulus sp. 以及外来入侵物种 Melanoides tuberculata、Pseudosuccinea columella 和 Physella acuta 组成。从 926 只蜗牛中分离出 104 只蜗牛（11.2%），有 6 种尾蚴型——哺乳动物血吸虫、禽血吸虫、长叉头蚴、棘口吸虫、单殖吸虫和尾蚴。PCR 显示感染率显著较高，70.2%的蜗牛检测出吸虫感染。蜗牛分类多样性和感染率在土地利用类型之间显著不同，在商业烟草农场部分观察到最低值，突出了农业对生物多样性的潜在不利影响。有大量 Lagarosiphon major（氧气杂草）覆盖的池塘似乎有利于 P. acuta 和 P. columella 的存在和丰度。B. truncatus 和 B. tropicus 等有血吸虫能力的蜗牛似乎更喜欢浅水和富营养化的地点，这些地点的硝酸盐、浮游植物生物量、浊度和藻蓝蛋白水平较高。这些池塘主要与挺水大型水生植物 Cladium mariscus 相关联，这表明它们与重要的中间宿主蜗牛之间存在潜在的关联。总之，我们的研究强调了环境因素、大型水生植物组成、土地利用以及淡水蜗牛的丰度、多样性和感染流行率之间的复杂相互作用，为针对人工水体中的蜗牛控制和疾病管理提供了潜在策略的见解。
