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对流行病学分析显示大珠母贝幼虫群体的死亡是以暴发性方式发生,从胚胎发育前期至变态期,幼虫存在两个死亡高峰,分别位于壳顶期之前或壳顶期和壳顶后期.大珠母贝幼虫群体的死亡率与RLO感染之间存在显著的相关性,在RLO感染的高峰之后均相应伴随幼虫群体死亡率的高峰,随着RLO感染率和感染强度的降低,幼虫群体死亡率也明显降低.在TEM下未发现未受精卵母细胞、受精卵和胚胎早期幼虫感染RLO,最先出现RLO包涵体阳性感染的时期为24h尚未摄食的D形期幼虫,故认为RLO可能不是通过垂直传播,而是通过外界接触感染的方式感染宿主,贝体感染至发病死亡存在潜伏期.
Epidemiological analysis showed that the death of Larix jejuni larvae occurred in a violent manner. From pre-embryonic development to metamorphosis, there were two death peaks in larvae, which were located before the apical stage or at the apical stage and late stage . There was a significant correlation between mortality and RLO infection in Larvae larvae population and the highest larval mortality after the peak of RLO infection. With the decrease of RLO infection rate and infection intensity, larval population Mortality was also significantly reduced.Under the TEM, no unfertilized oocyte, fertilized egg and early embryo larvae infected with RLO were found, the first occurrence of RLO inclusion body positive infection was not yet fed the D-phase larvae 24h, so that the RLO may Not through vertical transmission, but through contact with the outside world infection infection host, shellfish infection to the existence of the incubation period of incubation.