主要浮游微藻携带急性病毒性坏死症病毒(AVNV)的研究

Studies on phytoplanktons carrying and spreading AVNV

研究常见浮游微藻对栉孔扇贝"急性病毒性坏死症病毒"(AVNV)的黏附和携带,探讨微藻作为病毒水平传播媒介的可能性,进而了解AVNV的水平传播途径。我们选取培养17种海区常见浮游微藻,在微藻生长的指数增长期混入AVNV病毒粗提液,用PCR等分子检测法定期对试验微藻携带AVNV的情况进行检测。实验结果表明,亚心形扁藻、小球藻、绿色杜氏藻、四爿藻、中肋骨条藻和小新月菱形藻可以在一定时间内携带AVNV,占到实验微藻总数的35.3%。用携带AVNV的6种微藻投喂试验栉孔扇贝以分析其致病力,结果表明,试验扇贝表现出典型的急性病毒性死亡症状,在试验的9d时间内,6组感染组试验扇贝的累积死亡率均显著(P<0.05)或极显著(P<0.01)高于对照组,表明携带AVNV的微藻具有显著的致病性。本研究的结果表明,栉孔扇贝通过摄食携带AVNV的微藻而感染发病是可能的,浮游微藻可能是AVNV水平传播的重要传递体。

We studied the possible role that marine microalgae may play during the outbreaks of acute viral necrobiotic disease（ AVND） of cultured zhikong scallops（ Chlamys farreri） .In order to elucidate the possibility of marine microalgae carrying AVNV（ acute viral necrobiotic disease virus） ,seventeen species of microalgae were co-cultured with pure AVNV solution and were assayed daily by PCR to study whether they could carry AVNV.Further experiments were conducted to investigate whether the virus carried by microalgae could re-infect zhikong scallops.The results showed that 6 （ including Platymonas subcordiformis,Chlorella sp., Dunaliella viridis,and Tetraselmis tetrathele in Chlorophyta and Nitzschia closterium minutissima,and Skeletonema costatum in bacillariophyta） of 17 microalgae,which account for 35.3% of the tested algae,could carry AVNV,the AVNV detections in microalgae were positive during 96 to 144 h.The 6 AVNV-microalgae complex were fed to zhikong scallops,the tested scallops show a typical acute viral necrobiosis symptom,and the accumulated mortalities of scallops fed with the AVNV-microalgae complex were significant（ P0.05） or highly significant（ P0.01） compared with that of the control fed with mixture with 6 species microalgae during the nine-day experiment,which indicated that the AVNV-microalgae complex have an impressing ability to infect the scallops.Based on these laboratory challenges studies,the microalgae can serve as a vector in the horizontal pathway of transmission of AVNV via feeding or filtering process of scallops.