“Efficacy of Different Vaccine Administration Strategies Against North American and European Genotypes of Infectious Salmon Anemia Virus (Isav) in Atlantic Salmon (Salmo Salar L.) (7344)”

efficacy of different vaccine administration strategies against north american and european genotypes of infectious salmon anemia virus (isav) in atlantic salmon (salmo salar l.)

This study evaluated the efficacy of two vaccination strategies using two commercial multivalent vaccines with ISA components in Atlantic salmon challenged with North American (NA, HPR4) or European (European genotype, HPRnew, isolate recovered in Eastern Canada) genotypes of ISAv. Both isolates were recovered from confirmed cases in Eastern Canada. The treatment regimens included ALPHA JECT micro 7 ISA (AJ-7; Trt. B), AJ-7 followed by a booster using a competitor vaccine (Trt. C) administered post 500 degree-days, and a simultaneous injection of AJ-7 and the competitor vaccine (Trt. D). Efficacy was measured relative to a sham control group (Trt. A) injected with saline. See figure 1 for more details. Unvaccinated Atlantic salmon parr (St. John River stock, average weight 36.62 g) received the treatments. Post-seroconversion periods (1000 degree-days), unvaccinated fish (Trojans) were injected with either NA-ISAv or EU-ISAv and mixed into respective tanks. All vaccinated groups exhibited significantly higher survival compared to the unvaccinated control. Significant survival differences were not observed among the vaccinated groups against NA-ISAv, although the booster dose group showed the highest survival. When challenged with EU-ISAv, AJ-7 alone (Trt. B) or with competitor booster (Trt. C) had significantly higher survival than fish injected with both vaccines simultaneously (Trt. D) and controls (Trt. A). The treatments did not differentially affect growth or Speilberg scores, indicating the safety of all tested vaccine administration strategies.

1. Zanuzzo, Fabio, Onda, Author
2. Sarowar, Nasif, Onda, Author
3. Poley, Jordan, Onda, Author
4. Karlsen, Marius, Zoetis, Author
5. Ness, Michael, Zoetis, Author
6. Peach, Randy, Zoetis, Author
7. Lunheim, Ane Sandtrø, Zoetis, Presenter