Steenrod Camille L, Jones Jacob R, Marino John A
1 Department of Geography, University of Maryland, 2181 LeFrak Hall, College Park, Maryland 20740.
2 Department of Biology, Bradley University, 1501 West Bradley Avenue, Peoria, Illinois 61625.
J Parasitol. 2019 Aug;105(4):546-554.
Parasites can affect animal populations and communities in aquatic ecosystems. However, greater understanding is needed for the distributions and drivers of parasite infection levels in many areas. This study focuses on parasite prevalence (percent infected hosts) of an important class of parasites, trematodes, in 2 species of snail first intermediate hosts ( and sp.) in the Illinois River watershed, which has been impacted by human development. We hypothesized that trematode prevalence depends on local (e.g., water chemistry) and landscape (e.g., proximity to the Illinois River and land cover) factors. To test our hypotheses, we collected at least 20 individuals of 1 or both species of snails from 28 ponds within the watershed, and we made water-quality measurements and recorded habitat characteristics at each site. We then screened the snails for infections in the laboratory and identified the trematode cercariae that emerged based on morphological and molecular techniques. We found 5 cercariae morphotypes, including important parasites of wildlife, such as sp. and . Our results indicate that proximity to the Illinois River and open water or wetlands was positively associated with trematode prevalence in both snail species, whereas water chemistry (higher pH, lower calcium concentration, and lower specific conductance) was associated with increased prevalence, but only in . Our findings offer increased understanding of potential environmental drivers underlying trematode distributions, with implications for wildlife health.
寄生虫会影响水生生态系统中的动物种群和群落。然而，许多地区对于寄生虫感染水平的分布和驱动因素仍需更深入的了解。本研究聚焦于伊利诺伊河流域受人类活动影响的两种蜗牛（ 和 ）作为第一中间宿主时，一类重要寄生虫——吸虫的感染率（感染宿主的百分比）。我们假设吸虫感染率取决于局部因素（如水质化学）和景观因素（如与伊利诺伊河的距离及土地覆盖情况）。为验证我们的假设，我们从流域内的28个池塘中采集了至少20只一种或两种蜗牛，并对每个采样点进行了水质测量和栖息地特征记录。然后，我们在实验室中对蜗牛进行感染筛查，并基于形态学和分子技术鉴定出逸出的吸虫尾蚴。我们发现了5种尾蚴形态类型，包括野生动物的重要寄生虫，如 属和 属。我们的结果表明，对于两种蜗牛而言，靠近伊利诺伊河以及开放水域或湿地与吸虫感染率呈正相关，而水质化学因素（较高的pH值、较低的钙浓度和较低的电导率）与感染率增加有关，但仅在 中如此。我们的研究结果有助于更深入地了解吸虫分布背后潜在的环境驱动因素，对野生动物健康具有重要意义。
