Ubels John L, DeJong Randall J, Hoolsema Brittany, Wurzberger Amy, Nguyen Thuy-Tien, Blankespoor Harvey D, Blankespoor Curtis L
Department of Biology, Calvin College, Grand Rapids, MI, USA.
University of Michigan Biological Station, Pellston, MI, USA.
Int J Parasitol Parasites Wildl. 2018 May 6;7(2):171-179. doi: 10.1016/j.ijppaw.2018.05.001. eCollection 2018 Aug.
Histologic studies of fish from Douglas Lake, Cheboygan County, Michigan, USA show that spp. infect the lens of spottail shiners () and common shiners (). In contrast, infection was confined to the choroidal vasculature of yellow perch (), and the morphology of the pigment epithelium and retina in regions adjacent to the metacercariae was abnormal. The difference in location of metacercariae within the host suggested that different species may infect shiners and perch in Douglas Lake. Species diversity was investigated by sequencing the barcode region of the cytochrome oxidase I gene of metacercariae. Four species of were identified, all four of which were present in shiner lenses; however, only was present in the perch choroid. To determine whether infection of perch eyes affects the response of the retina to a light stimulus, electroretinograms (ERG) were recorded. The amplitude of the b-wave of the ERG was reduced and the b-wave latency was increased in infected perch, as compared to uninfected eyes, and the flicker-fusion frequency was also reduced. Infection of the yellow perch choroid by , which shows strong host and tissue specificity, has an adverse effect on retinal function, lending support to the hypothesis that parasite-induced impairment of host vision may afford the evolutionary benefit of increasing the likelihood of transmission, via host fish predation, to its definitive avian host.
对来自美国密歇根州切博伊根县道格拉斯湖的鱼类进行的组织学研究表明，[具体物种]感染了细纹鳟（[学名]）和钝吻米诺鱼（[学名]）的晶状体。相比之下，感染局限于黄斑鲈（[学名]）的脉络膜血管，并且在尾蚴附近区域的色素上皮和视网膜形态异常。宿主内尾蚴位置的差异表明，不同的[具体物种]可能感染道格拉斯湖中的米诺鱼和鲈鱼。通过对尾蚴细胞色素氧化酶I基因的条形码区域进行测序来研究物种多样性。鉴定出了四种[具体物种]，所有这四种都存在于米诺鱼的晶状体中；然而，只有[具体物种]存在于鲈鱼的脉络膜中。为了确定鲈鱼眼睛的感染是否会影响视网膜对光刺激的反应，记录了视网膜电图（ERG）。与未感染的眼睛相比，感染鲈鱼的ERG的b波振幅降低，b波潜伏期延长，并且闪烁融合频率也降低。具有强烈宿主和组织特异性的[具体物种]对黄斑鲈脉络膜的感染对视网膜功能有不利影响，这支持了以下假设：寄生虫引起的宿主视力损害可能通过宿主鱼类被捕食为[具体物种]提供进化益处，从而增加其传播到最终鸟类宿主的可能性。
