BioProject

Infectious diseases among fish present an important economic burden for the aquaculture and fisheries industries around the world. More...

Infectious diseases among fish present an important economic burden for the aquaculture and fisheries industries around the world. For example, the infectious salmon anemia virus (ISAV) is known to infect farmed Atlantic salmon (Salmo salar), and results in millions of dollars of lost revenue to salmon farmers. Although improved management and husbandry practices over the last few years have minimized the losses and the number of outbreaks, the risk of new virulent isolates emerging is still a looming threat to the viability and sustainability of this industry. An understanding of the host-pathogen interactions at the molecular level during the course of an infection thus remains of strategic importance for the development of molecular tools and efficient vaccines capable of minimizing losses in the eventual case of a new outbreak. Using a 32 k cDNA microarray platform (cGRASP), we have studied various signaling pathways and immune regulated genes, activated or repressed, in Atlantic salmon head-kidney during the course of an ISAV infection. Gene expressions were measured at 5 different time-points: 6h, 24h, 3d, 7d and 16d post infection to get an overall view of changes as they occurred in time. The earliest time points showed only a few differentially expressed genes in infected fish, relative to controls, although as time progressed, many additional genes involved in key defense pathways were up-regulated including MHC type I, beta-2 microglobulin, TRIM 25 and CC-chemokine 19. During the latest stage of the infection process, many genes related to oxygen transportation were under-expressed, which correlates well with the anemia observed prior to death in Atlantic salmon infected with virulent strains of ISAV. Overall design: Atlantic salmon smolts from 2 families of Atlantic salmon were IP injected with either 0.1mL of 10e5 TCID50 mL-1 of virus or 0.1mL of sham solution (L15 culture medium) and divided equally in four 1000 L tanks: 2 duplicate tanks containing ISAV injected fish and 2 duplicate control tanks containing sham solution injected fish. Four fish per family were sampled immediately prior to injection. An additional two fish per family per tank (four fish per family total) were sampled at 6h, 24h, 3d, 7d and 16d post injection. Head-kidney was dissected from each fish and used for microarray analysis. ISAV infected Atlantic salmon were compared to non-infected Atlantic salmon for each time-point. Less...