Heterosporis sutherlandae is an invasive microsporidian parasite in the Great Lakes region of North America that infects the skeletal muscle of numerous fish species, rendering the filet unfit for human consumption. Although H. sutherlandae has been identified as a pathogen of concern by state management agencies, there is little information to inform regulation and intervention. We sampled fishes over one year from three lakes in northern Minnesota with known infected populations to determine the importance of host demographic and environmental variables to H. sutherlandae infection prevalence. Heterosporis sutherlandae was present during all sampling periods, ranging in prevalence from 1-11%. The prevalence of H. sutherlandae varied significantly according to season, with winter having the lowest prevalence among Yellow Perch Perca flavescens (1%), and summer having the highest prevalence (11%). For fishes of other species, the prevalence of H. sutherlandae also varied significantly with season, where the lowest prevalence occurred during the spring (1%) and the highest in fall (9%). Rates of pathogen transmission were estimated by exposing Fathead Minnows Pimephales promelas in the laboratory. Transmission rates were 23% when naïve fish were fed infected tissues, and only 2% when naïve fish were cohabitated with tissue-fed fish. Exposure method and time exposed increased the probability that a fish was infected with H. sutherlandae. These findings suggest that H. sutherlandae transmission is greater when a susceptible host consumes infected tissue than exposure to spores present in the water column. The current rates of infection in wild fishes is in stark contrast to the prevalence documented in 2004 (28%), suggesting a reduction in H. sutherlandae prevalence within at least one Yellow Perch population in the Laurentian Great Lakes region since the early 2000s.

中文翻译：

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微孢子虫的现场和实验室评估，Heterosporis sutherlandae 流行、严重程度和传播

Heterosporis sutherlandae 是北美五大湖地区的一种侵入性微孢子虫寄生虫，可感染多种鱼类的骨骼肌，使鱼片不适合人类食用。尽管 H. sutherlandae 已被国家管理机构确定为关注的病原体，但几乎没有信息可用于监管和干预。我们从明尼苏达州北部的三个湖泊中对已知受感染种群的鱼类进行了一年多的采样，以确定宿主人口统计和环境变量对 H. sutherlandae 感染流行的重要性。Heterosporis sutherlandae 在所有采样期间都存在，流行率为 1-11%。H. sutherlandae 流行率随季节变化显着，冬季在 Yellow Perca Perca flavescens 中的流行率最低 (1%)，而夏季的流行率最高 (11%)。对于其他种类的鱼类，H. sutherlandae 的流行率也随季节变化显着，春季最低（1%）和秋季最高（9%）。通过在实验室中暴露 Fathead Minnows Pimephales promelas 来估计病原体传播率。当幼稚鱼喂食受感染的组织时，传播率为 23%，而当幼稚鱼与组织喂养的鱼同居时，传播率仅为 2%。暴露方法和暴露时间增加了鱼感染 H. sutherlandae 的可能性。这些发现表明，当易感宿主消耗受感染的组织时，H. sutherlandae 的传播比暴露于水柱中存在的孢子要大。