Audemard C, Ragone Calvo L M, Paynter K T, Reece K S, Burreson E M
Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, Gloucester Point, USA.
Parasitology. 2006 Jun;132(Pt 6):827-42. doi: 10.1017/S0031182006009851. Epub 2006 Feb 14.
Perkinsus marinus is a severe pathogen of the oyster Crassostrea virginica on the East Coast of the United States. Transmission dynamics of this parasite were investigated in situ for 2 consecutive years (May through October) at 2 lower Chesapeake Bay sites. Compared to previous studies where seasonal infection patterns in oysters were measured, this study also provided parasite water column abundance data measured using real-time PCR. As previously observed, salinity and temperature modulated parasite transmission dynamics. Using regression analysis, parasite prevalence, oyster mortalities and parasite water column abundance were significantly positively related to salinity. Perkinsus marinus weighted prevalence in wild oysters and parasite water column abundance both were significantly related to temperature, but the responses lagged 1 month behind temperature. Parasite water column abundance was the highest during August (up to 1,200 cells/l) and was significantly related to P. marinus weighted prevalence in wild oysters, and to wild oyster mortality suggesting that parasites are released in the environment via both moribund and live hosts (i.e. through feces). Incidence was not significantly related to parasite water column abundance, which seems to indicate the absence of a linear relationship or that infection acquisition is controlled by a more complex set of parameters.
海派金虫是美国东海岸弗吉尼亚牡蛎的一种严重病原体。连续两年（5月至10月）在切萨皮克湾下游的两个地点对这种寄生虫的传播动态进行了实地调查。与之前测量牡蛎季节性感染模式的研究相比，本研究还提供了使用实时PCR测量的寄生虫水柱丰度数据。如先前观察到的，盐度和温度调节了寄生虫的传播动态。通过回归分析，寄生虫患病率、牡蛎死亡率和寄生虫水柱丰度与盐度显著正相关。野生牡蛎中海派金虫的加权患病率和寄生虫水柱丰度均与温度显著相关，但响应滞后于温度1个月。寄生虫水柱丰度在8月最高（高达1200个细胞/升），并且与野生牡蛎中海派金虫的加权患病率以及野生牡蛎死亡率显著相关，这表明寄生虫通过濒死和活的宿主（即通过粪便）释放到环境中。发病率与寄生虫水柱丰度没有显著关系，这似乎表明不存在线性关系或感染获取受一组更复杂参数的控制。
