Hershberger P K, Gregg J L, Grady C A, Taylor L, Winton J R
Marrowstone Marine Field Station, US Geological Survey-Western Fisheries Research Center, Nordland, Washington 98358, USA.
Dis Aquat Organ. 2010 Dec 7;93(1):43-9. doi: 10.3354/dao02283.
Chronic viral hemorrhagic septicemia virus (VHSV) infections were established in a laboratory stock of Pacific herring Clupea pallasii held in a large-volume tank supplied with pathogen-free seawater at temperatures ranging from 6.8 to 11.6 degrees C. The infections were characterized by viral persistence for extended periods and near-background levels of host mortality. Infectious virus was recovered from mortalities occurring up to 167 d post-exposure and was detected in normal-appearing herring for as long as 224 d following initial challenge. Geometric mean viral titers were generally as high as or higher in brain tissues than in pools of kidney and spleen tissues, with overall prevalence of infection being higher in the brain. Upon re-exposure to VHSV in a standard laboratory challenge, negligible mortality occurred among groups of herring that were either chronically infected or fully recovered, indicating that survival from chronic manifestations conferred protection against future disease. However, some survivors of chronic VHS infections were capable of replicating virus upon re-exposure. Demonstration of a chronic manifestation of VHSV infection among Pacific herring maintained at ambient seawater temperatures provides insights into the mechanisms by which the virus is maintained among populations of endemic hosts.
在一个大型水箱中，以6.8至11.6摄氏度的无病原体海水饲养的太平洋鲱鱼（Clupea pallasii）实验室种群中建立了慢性病毒性出血性败血症病毒（VHSV）感染。这些感染的特征是病毒长期持续存在，宿主死亡率接近背景水平。在接触病毒后长达167天发生的死亡个体中可回收感染性病毒，并且在初次感染后长达224天的外观正常的鲱鱼中可检测到病毒。脑组织中的几何平均病毒滴度通常与肾和脾组织池中的滴度一样高或更高，感染的总体患病率在脑中更高。在标准实验室挑战中再次接触VHSV时，慢性感染或完全恢复的鲱鱼组中的死亡率可忽略不计，这表明慢性感染后的存活赋予了对未来疾病的保护作用。然而，一些慢性VHS感染的幸存者在再次接触时能够复制病毒。在环境海水温度下饲养的太平洋鲱鱼中VHSV感染慢性表现的证明，为该病毒在地方宿主种群中维持的机制提供了见解。
