title: Adverse and long-term protective effects following oil-adjuvanted vaccination against Aeromonas salmonicida in rainbow trout.
abstract: Prophylactic measures against Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis, have been an active field of research for decades, with studies mainly focused on Atlantic salmon (Salmo salar). In the present study we have examined the protective and adverse effects of mineral oil-adjuvanted injection vaccines on rainbow trout (Oncorhynchus mykiss). A commercial vaccine and an experimental auto vaccine, as well as their respective adjuvant formulations alone were used to evaluate their individual effects, both prior to and during an experimental waterborne infection challenge. Macro- and microscopic examination revealed signs of vaccine-induced adverse effects from 10 weeks to 14 months post vaccination. Both vaccines induced statistically significant protection during the experimental challenge (P=0.018 for both vaccines), as well as significantly elevated levels of specific circulating antibodies prior to and during the experimental challenge when compared to an unvaccinated control group. During the early, critical time points of the infection, both vaccines appeared to protect against pathological changes to the liver and spleen, which provides a probable explanation for the reduced mortality seen in the vaccinated groups. A significant correlation was found between the level of A. salmonicida-specific antibodies measured prior to challenge and the endpoint survival of each group after the experimental infection, and furthermore, the levels of these antibodies remained elevated for at least 14 months post vaccination.
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Dyrlægevej 88, 1870 Frederiksberg C, Denmark. Electronic address: krv@sund.ku.dk.
authors.forename: Kasper Rømer
authors.initials: KR
authors.lastname: Villumsen
authors.affiliation: Department of Basic Science and Aquatic Medicine, Norwegian School of Veterinary Science, Ullevålsveien 72, 0033 Oslo, Norway.
authors.forename: Erling Olaf
authors.initials: EO
authors.lastname: Koppang
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Dyrlægevej 88, 1870 Frederiksberg C, Denmark.
authors.forename: Martin Kristian
authors.initials: MK
authors.lastname: Raida
mesh_terms: D048409:Aeromonas salmonicida / Q000187:drug effects*; D000704:Analysis of Variance; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D017756:Aquaculture / Q000379:methods; D001428:Bacterial Vaccines / Q000009:adverse effects / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005393:Fish Diseases / Q000382:microbiology* / Q000517:prevention & control*; D016905:Gram-Negative Bacterial Infections / Q000517:prevention & control / Q000662:veterinary*; D009284:Naphthols; D017686:Oncorhynchus mykiss; D018709:Statistics, Nonparametric; D014611:Vaccination / Q000009:adverse effects / Q000662:veterinary*
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D009284:Naphthols; C057508:Martius yellow
keywords: Adverse effect; Aeromonas salmonicida; Long-term protection; Pathology; Vaccination