Embar-Gopinath Sridevi, Butler Rick, Nowak Barbara
School of Aquaculture, University of Tasmania, Launceston, Tasmania 7250, Australia.
Dis Aquat Organ. 2005 Nov 9;67(1-2):55-60. doi: 10.3354/dao067055.
The relationship between salmonid gill bacteria and Neoparamoeba sp., the aetiological agent of amoebic gill disease (AGD) was determined in vivo. Fish were divided into 4 groups and were subjected to following experimental infections: Group 1, amoebae only; Group 2, Staphylococcus sp. and amoebae; Group 3, Winogradskyella sp. and amoebae; Group 4, no treatment (control). Fish (Groups 1, 2 and 3) were exposed to potassium permanganate to remove the natural gill microflora prior to either bacterial or amoebae exposure. AGD severity was quantified by histological analysis of gill sections to determine the percentage of lesioned filaments and the number of affected lamellae within each lesion. All amoebae infected groups developed AGD, with fish in Group 3 showing significantly more filaments with lesions than other groups. Typically lesion size averaged between 2 to 4 interlamellar units in all AGD infected groups. The results suggest that the ability of Neoparamoeba sp. to infect filaments and cause lesions might be enhanced in the presence of Winogradskyella sp. The possibility is proposed that the prevalence of more severe AGD is due to the occurrence of Winogradskyella sp. at high concentrations on the gills.
在体内确定了鲑科鱼类鳃部细菌与阿米巴鳃病（AGD）病原体新帕拉变形虫属之间的关系。将鱼分为4组，并进行以下实验性感染：第1组，仅感染变形虫；第2组，感染葡萄球菌属和变形虫；第3组，感染维诺格拉德斯基菌属和变形虫；第4组，不进行处理（对照组）。在暴露于细菌或变形虫之前，第1、2和3组的鱼用高锰酸钾处理以去除天然鳃部微生物群。通过对鳃切片进行组织学分析来量化AGD的严重程度，以确定病变鳃丝的百分比以及每个病变中受影响鳃小片的数量。所有感染变形虫的组都患上了AGD，第3组的鱼显示出有病变的鳃丝比其他组明显更多。在所有感染AGD的组中，典型的病变大小平均在2至4个鳃小片间距单位之间。结果表明，在维诺格拉德斯基菌属存在的情况下，新帕拉变形虫属感染鳃丝并引起病变的能力可能会增强。有人提出，更严重的AGD流行是由于鳃部高浓度存在维诺格拉德斯基菌属。
