Institute of Marine Research, Bergen, Norway.
Department of Biological Sciences, University of Bergen, Bergen, Norway.
Parasitology. 2023 Sep;150(11):990-1005. doi: 10.1017/S0031182023000847. Epub 2023 Sep 14.
Atlantic salmon () is repeatedly exposed to and infected with ectoparasitic salmon lice () both in farms and in nature. However, this is not reflected in laboratory experiments where fish typically are infected only once. To investigate if a previous lice infection affects host response to subsequent infections, fish received 4 different experimental treatments; including 2 groups of fish that had previously been infected either with adult or infective salmon lice larvae (copepodids). Thereafter, fish in all treatment groups were infected with either a double or a single dose of copepodids originating from the same cohort. Fish were sampled when lice had developed into the chalimus, the pre-adult and the adult stage, respectively. Both the specific growth rate and cortisol levels (i.e. a proxy for stress) of the fish differed between treatments. Lice success (i.e. ability to infect and survive on the host) was higher in naïve than in previously infected fish (pre-adult stage). The expression of immune and wound healing transcripts in the skin also differed between treatments, and most noticeable was a higher upregulation early in the infection in the group previously infected with copepodids. However, later in the infection, the least upregulation was observed in this group, suggesting that previous exposure to salmon lice affects the response of Atlantic salmon towards subsequent lice infections.
大西洋鲑鱼（）在养殖场和自然环境中反复受到外寄生虫鲑虱（）的感染。然而，在实验室实验中并非如此，因为鱼类通常只会受到一次感染。为了研究先前的虱感染是否会影响宿主对后续感染的反应，研究人员对鱼类进行了 4 种不同的实验处理；包括两组先前分别感染过成年或感染性鲑虱幼虫（桡足类）的鱼类。此后，所有处理组的鱼类均感染了源自同一批的双剂量或单剂量桡足类幼虫。当虱发育成毛蚴、预成体和成虫阶段时，分别对鱼类进行采样。鱼类的特定增长率和皮质醇水平（即压力的替代物）在处理之间存在差异。与先前感染过的鱼类（预成体阶段）相比，未感染过的鱼类（幼鱼）中虱的成功率（即感染和在宿主上存活的能力）更高。皮肤中免疫和伤口愈合转录本的表达也因处理而异，最明显的是先前感染桡足类的鱼类在感染早期的上调幅度更高。然而，在感染后期，该组的上调幅度最小，这表明先前接触过鲑虱会影响大西洋鲑鱼对后续虱感染的反应。
