Fredensborg B L, Ramirez J J, Partida L
Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark;
J Parasitol. 2013 Dec;99(6):1129-32. doi: 10.1645/12-164.1. Epub 2013 May 3.
In this study, we investigated oysters, Crassostrea virginica , from Laguna Madre in South Texas, where a 45-yr old study recorded metacercarial infections of the echinostomatid trematode, Acanthoparyphium spinulosum , an Asian relative of which, Acanthoparyphium tyosenense, has been associated with human infections via the ingestion of raw mollusks. In an effort to examine the base-line infection parameters of Acanthoparyphium sp. in oysters, we examined the effect of distance from the shoreline, which is the habitat of the first intermediate host snail, Cerithidea pliculosa, as well as temporal changes in oyster infection levels, by conducting quarterly collections of oysters during a year. We found that almost all oysters (prevalence = 97.8-100%) were infected regardless of distance to the shoreline and season. However, the abundance of metacercariae was significantly higher close to the shoreline, while no significant temporal changes could be detected. In addition to the echinostomatid, we found a high abundance of the metacestode Tylocephalum sp. and the presence of 4 other metazoan parasites. None of the infections seemed to incur significant tissue damage to the oysters. Our study shows that at least locally, recreational harvesters of oysters may be exposed to Acanthoparyphium sp. Future studies should examine oysters from snail host habitats in the Gulf of Mexico, and the potential zoonotic risk of Acanthoparyphium sp. should be evaluated using experimental infections of animal models.
在本研究中，我们调查了得克萨斯州南部拉古纳马德雷湾的弗吉尼亚牡蛎（Crassostrea virginica）。在一项长达45年的研究中记录到，这些牡蛎感染了棘口吸虫（Acanthoparyphium spinulosum）的尾蚴，该吸虫的一个亚洲近亲——棘口吸虫（Acanthoparyphium tyosenense），已被证实可通过生食软体动物导致人类感染。为了研究棘口吸虫属（Acanthoparyphium sp.）在牡蛎中的基线感染参数，我们考察了与海岸线距离的影响（第一中间宿主蜗牛——扭旋沼螺（Cerithidea pliculosa）的栖息地为海岸线），以及牡蛎感染水平随时间的变化，方法是在一年中按季度采集牡蛎。我们发现，几乎所有牡蛎（感染率 = 97.8 - 100%）无论与海岸线的距离远近及季节如何，均受到感染。然而，靠近海岸线处尾蚴的丰度显著更高，而未检测到明显的时间变化。除了棘口吸虫，我们还发现了大量的多头绦虫属（Tylocephalum sp.）的中绦期幼虫以及其他4种后生动物寄生虫。这些感染似乎均未对牡蛎造成明显的组织损伤。我们的研究表明，至少在当地，牡蛎的休闲捕捞者可能会接触到棘口吸虫属。未来的研究应检查来自墨西哥湾蜗牛宿主栖息地的牡蛎，并使用动物模型的实验性感染来评估棘口吸虫属的潜在人畜共患病风险。
