Drummond Linda C, Balboa Sabela, Beaz Roxana, Mulcahy Máire F, Barja Juan L, Culloty Sarah C, Romalde Jesús L
Department of Zoology, Ecology and Plant Science, University College Cork, The Cooperage, Distillery Fields, North Mall, Cork, Ireland.
J Invertebr Pathol. 2007 May;95(1):1-8. doi: 10.1016/j.jip.2006.11.010. Epub 2007 Jan 11.
Brown Ring Disease (BRD), which affects the Manila clam in Europe, is caused by the bacterium, Vibrio tapetis. BRD has been diagnosed in Ireland on only one occasion (1997) although the aetiological agent has recently been detected in apparently healthy Manila clams from a number of sites around the Irish coast. The present work investigated the susceptibilities to BRD of two stocks of Manila clams, one from Ireland and the second from Galicia, north-western Spain, where BRD has been reported on a number of occasions. Exposure of the clams was by addition of V. tapetis to the holding waters. Development of BRD was assessed by the appearance of brown ring signs on the host shells, by bacterial isolation and characterization, and by detection of the bacterium by PCR. The pathogen was recovered from infected individuals and confirmed as V. tapetis by biochemical tests and a slide agglutination test. Galician clams experienced significantly higher mortalities, BRD prevalences and V. tapetis levels than Irish clams. Background infection with V. tapetis in the control stocks prevented conclusions being drawn on comparative susceptibility of the two stocks. Irish clams were significantly affected by the experimental challenge, as demonstrated by the development of BRD and an increase in V. tapetis levels. Results illustrate the vulnerability of Irish clams to BRD and have implications for the movement and transfer of clam seed in Ireland.
褐环病（BRD）影响欧洲的菲律宾蛤仔，由塔氏弧菌引起。尽管最近在爱尔兰沿海多个地点的看似健康的菲律宾蛤仔中检测到了病原体，但褐环病仅在1997年在爱尔兰被诊断出一次。目前的研究调查了两批菲律宾蛤仔对褐环病的易感性，一批来自爱尔兰，另一批来自西班牙西北部的加利西亚，该地区曾多次报告出现褐环病。通过向养殖水体中添加塔氏弧菌来使蛤仔接触病原体。通过观察宿主贝壳上褐环症状的出现、细菌分离和鉴定以及通过聚合酶链反应检测细菌来评估褐环病的发展情况。从受感染个体中分离出病原体，并通过生化试验和玻片凝集试验确认为塔氏弧菌。加利西亚蛤仔的死亡率、褐环病患病率和塔氏弧菌水平显著高于爱尔兰蛤仔。对照种群中塔氏弧菌的背景感染使得无法得出关于这两批蛤仔相对易感性的结论。爱尔兰蛤仔受到实验性挑战的显著影响，褐环病的出现和塔氏弧菌水平的增加证明了这一点。结果表明爱尔兰蛤仔对褐环病的易感性，并对爱尔兰蛤仔苗种的移动和转移具有影响。
