Jakob E, Barker D E, Garver K A
Fisheries & Oceans Canada, Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia V9T 6N7, Canada.
Dis Aquat Organ. 2011 Dec 6;97(2):155-65. doi: 10.3354/dao02414.
To better understand the role of vector transmission of aquatic viruses, we established an in vivo virus-parasite challenge specifically to address (1) whether Lepeophtheirus salmonis can acquire infectious haematopoietic necrosis virus (IHNV) after water bath exposure or via parasitizing infected Atlantic salmon Salmo salar and if so, define the duration of this association and (2) whether L. salmonis can transmit IHNV to naive Atlantic salmon and whether this transmission requires attachment to the host. Salmon lice which were water bath-exposed to 1 x 10(5) plaque-forming units (pfu) ml(-1) of IHNV for 1 h acquired the virus (2.1 x 10(4) pfu g(-1)) and remained IHNV-positive for 24 h post exposure. After parasitizing IHNV-infected hosts (viral titer in fish mucus 3.3 x 10(4) pfu ml(-1)) salmon lice acquired IHNV (3.4 x 10(3) pfu g(-1)) and remained virus-positive for 12 h. IHNV-positive salmon lice generated through water bath exposure or after parasitizing infected Atlantic salmon successfully transmitted IHNV, resulting in 76.5 and 86.6% of the exposed Atlantic salmon testing positive for IHNV, respectively. In a second experiment, only salmon lice that became IHNV-positive through water bath exposure transmitted IHNV to 20% of the naive fish, and no virus was transmitted when IHNV-infected salmon lice were cohabitated but restrained from attaching to naive fish. Under laboratory conditions, adult L. salmonis can acquire IHNV and transmit it to naive Atlantic salmon through parasitism. However, the ephemeral association of IHNV with L. salmonis indicates that the salmon louse act as a mechanical rather than a biological vector or reservoir.
为了更好地理解水生病毒的载体传播作用，我们专门建立了一项体内病毒 - 寄生虫挑战实验，以解决以下问题：（1）鲑鱼虱在水浴暴露后或通过寄生感染的大西洋鲑鱼（Salmo salar）是否能够感染传染性造血坏死病毒（IHNV），如果可以，确定这种关联的持续时间；（2）鲑鱼虱是否能够将IHNV传播给未感染的大西洋鲑鱼，以及这种传播是否需要附着在宿主上。将鲑鱼虱置于含有1×10⁵ 蚀斑形成单位（pfu）/毫升的IHNV的水浴中暴露1小时后，它们获得了病毒（2.1×10⁴ pfu/克），并且在暴露后24小时内仍为IHNV阳性。在寄生感染了IHNV的宿主后（鱼黏液中的病毒滴度为3.3×10⁴ pfu/毫升），鲑鱼虱获得了IHNV（3.4×10³ pfu/克），并在12小时内保持病毒阳性。通过水浴暴露或寄生感染的大西洋鲑鱼产生的IHNV阳性鲑鱼虱成功传播了IHNV，分别导致76.5%和86.6%的暴露大西洋鲑鱼检测出IHNV呈阳性。在第二项实验中，只有通过水浴暴露而变为IHNV阳性的鲑鱼虱将IHNV传播给了20%的未感染鱼，当感染了IHNV的鲑鱼虱同居但被限制附着在未感染鱼上时，没有病毒传播。在实验室条件下，成年鲑鱼虱可以获得IHNV并通过寄生将其传播给未感染的大西洋鲑鱼。然而，IHNV与鲑鱼虱的短暂关联表明，鲑鱼虱作为一种机械载体而非生物载体或储存宿主。
