School of Public Health, 357F South Academic Building, University of Alberta, Edmonton, AB, T6G 2G7, Canada.
Invertebrate Zoology, Royal Alberta Museum, 9810 103A Ave, Edmonton, AB, T5J 0G2, Canada.
Environ Health. 2018 Oct 25;17(1):73. doi: 10.1186/s12940-018-0417-7.
Cercarial dermatitis, colloquially "swimmer's itch", is a rash contracted in natural bodies of water, when people are exposed to skin-penetrating, larval flatworm parasites of the family Schistosomatidae, that emerge from aquatic snails. Swimmer's itch is a globally-distributed, allergic condition, of which we know very little regarding local dynamics of transmission. This study aims to gather relevant information on swimmer's itch in Canada, from multiple perspectives, including the human experience, parasite and host presence and distributions, and insight from historical perspectives.
Herein we utilize a mixed-methods approach towards examining the environmental health issue of swimmer's itch in Canadian lakes from a nation-wide viewpoint, with an example from Alberta. We examine the human perspective of having contracted swimmer's itch through a self-reporting surveillance system implemented over a 5-year period. We also conducted a 3-year species survey of parasites and intermediate snail hosts within lakes in central Alberta and compiled this data with snail and vertebrate (definitive) host survey data from across Alberta to examine potential for future spread. We compare the results from our surveys to a historical review of the literature to examine the extent of swimmer's itch across Canada and identify where future efforts should be focused.
Over 3800 cases of swimmer's itch were captured across Canada by the self-reporting surveillance system. Swimmer's itch cases were reported from every province except Prince Edward Island. Species surveys in Alberta revealed 7 new parasite and host records, with potential for swimmer's itch to occur throughout most of the province based on host distributions. A review and comparison to the literature has highlighted several knowledge gaps surrounding schistosome species, host species and their distributions and contributions towards swimmer's itch.
Swimmer's itch is a greater environmental health hazard across Canada than previous literature would have alluded. This study provides proof-of-concept for the utility of a self-reporting surveillance system for swimmer's itch in Canada. Recommendations are made towards implementing a systems-thinking approach that incorporates citizen-scientists for future research, management, and policy surrounding swimmer's itch.
类圆线虫性皮炎，俗称“游泳者痒”，是一种在天然水体中接触到穿透皮肤的、幼虫期扁形动物科的吸虫后引起的皮疹，这些幼虫从水生蜗牛中孵化出来。游泳者痒是一种全球分布的过敏症，我们对其传播的局部动态知之甚少。本研究旨在从多个角度收集加拿大游泳者痒的相关信息，包括人类体验、寄生虫和宿主的存在和分布，以及历史视角的见解。
在此，我们采用混合方法从全国角度研究加拿大湖泊中的游泳者痒这一环境健康问题，以艾伯塔省为例。我们通过 5 年期间实施的自我报告监测系统来研究人类感染游泳者痒的情况。我们还对艾伯塔省中部湖泊中的寄生虫和中间蜗牛宿主进行了为期 3 年的物种调查，并将这些数据与艾伯塔省各地的蜗牛和脊椎动物（终末）宿主调查数据汇编在一起，以检查未来传播的潜力。我们将我们的调查结果与文献回顾进行比较，以检查游泳者痒在加拿大的广泛程度，并确定未来应集中精力的地方。
通过自我报告监测系统，在加拿大各地共捕获了 3800 多例游泳者痒病例。除爱德华王子岛外，所有省份均有游泳者痒病例报告。在艾伯塔省的物种调查中发现了 7 种新的寄生虫和宿主记录，根据宿主分布，游泳者痒可能在该省大部分地区发生。回顾和与文献比较突出了几个关于血吸虫物种、宿主物种及其分布以及对游泳者痒的贡献的知识空白。
游泳者痒在加拿大是一个比以前的文献所暗示的更大的环境健康危害。本研究为加拿大游泳者痒自我报告监测系统的实用性提供了概念验证。建议采取系统思维方法，将公民科学家纳入未来有关游泳者痒的研究、管理和政策中。
