Lund Morten, Røsæg Magnus Vikan, Krasnov Aleksei, Timmerhaus Gerrit, Nyman Ingvild Berg, Aspehaug Vidar, Rimstad Espen, Dahle Maria Krudtaa
Section of Immunology, Norwegian Veterinary Institute, Oslo, Norway.
SalMar ASA, Kverva, Norway.
Vet Res. 2016 Oct 21;47(1):107. doi: 10.1186/s13567-016-0389-y.
Viral diseases are among the main challenges in farming of Atlantic salmon (Salmo salar). The most prevalent viral diseases in Norwegian salmon aquaculture are heart and skeletal muscle inflammation (HSMI) caused by Piscine orthoreovirus (PRV), and pancreas disease (PD) caused by Salmonid alphavirus (SAV). Both PRV and SAV target heart and skeletal muscles, but SAV additionally targets exocrine pancreas. PRV and SAV are often present in the same locations and co-infections occur, but the effect of this crosstalk on disease development has not been investigated. In the present experiment, the effect of a primary PRV infection on subsequent SAV infection was studied. Atlantic salmon were infected with PRV by cohabitation, followed by addition of SAV shedder fish 4 or 10 weeks after the initial PRV infection. Histopathological evaluation, monitoring of viral RNA levels and host gene expression analysis were used to assess disease development. Significant reduction of SAV RNA levels and of PD specific histopathological changes were observed in the co-infected groups compared to fish infected by SAV only. A strong correlation was found between histopathological development and expression of disease related genes in heart. In conclusion, experimentally PRV infected salmon are less susceptible to secondary SAV infection and development of PD.
病毒性疾病是大西洋鲑（Salmo salar）养殖中的主要挑战之一。挪威鲑鱼养殖中最常见的病毒性疾病是由鱼正呼肠孤病毒（PRV）引起的心脏和骨骼肌炎症（HSMI），以及由鲑鱼α病毒（SAV）引起的胰腺疾病（PD）。PRV和SAV都靶向心脏和骨骼肌，但SAV还靶向外分泌胰腺。PRV和SAV常存在于相同位置并发生共同感染，但这种相互作用对疾病发展的影响尚未得到研究。在本实验中，研究了原发性PRV感染对随后SAV感染的影响。通过同居使大西洋鲑感染PRV，然后在初次PRV感染后4周或10周添加感染SAV的鱼。采用组织病理学评估、病毒RNA水平监测和宿主基因表达分析来评估疾病发展。与仅感染SAV的鱼相比，在共同感染组中观察到SAV RNA水平和PD特异性组织病理学变化显著降低。在心脏中，组织病理学发展与疾病相关基因的表达之间发现了很强的相关性。总之，实验性感染PRV的鲑鱼对继发性SAV感染和PD发展的易感性较低。
