title: Association of spinal deformity and vaccine-induced abdominal lesions in harvest-sized Atlantic salmon, Salmo salar L.
abstract: Spinal deformities in Atlantic salmon, Salmo salar L., have been described as a disease of multifactorial origin for which vaccines and time of vaccination have been suggested as risk factors. A vaccine efficacy trial where spinal deformity became evident was continued by the observational study reported here. In the preharvest part of the study 17 months post-sea transfer, there was a prevalence of 11.3% spinal deformity, with deformities present only in one vaccine group indicating a strong vaccine involvement. At slaughter, the prevalence of spinal deformities was 11.7%, and deformed fish had only 62% of normal slaughter weight. Visual analogue scales (VAS) were used for continuous recordings of vaccine-induced abdominal lesions and deformity. A logistic regression model associating presence of spinal deformity with markers of abdominal lesions was developed. The odds ratio for spinal deformity was 5.7 (95% CI: 3.4-9.4) for each unit increase in adhesion score (0-6) and 4.9 (2.9-3.4) for each unit increase in melanin on abdominal organs (0-3). Lesions in the dorsal caudal part of the abdomen gave an odds ratio for spinal deformity of 2.2.
authors.affiliation: Norwegian School of Veterinary Science, Oslo, Norway. arnfinn.aunsmo@veths.no
authors.forename: A
authors.initials: A
authors.lastname: Aunsmo
authors.forename: A
authors.initials: A
authors.lastname: Guttvik
authors.forename: P J
authors.initials: PJ
authors.lastname: Midtlyng
authors.forename: R B
authors.initials: RB
authors.lastname: Larssen
authors.forename: O
authors.initials: O
authors.lastname: Evensen
authors.forename: E
authors.initials: E
authors.lastname: Skjerve
mesh_terms: D000005:Abdomen / Q000473:pathology; D000818:Animals; D001428:Bacterial Vaccines / Q000009:adverse effects*; D016022:Case-Control Studies; D005398:Fisheries / Q000191:economics; D016015:Logistic Models; D015995:Prevalence; D011859:Radiography; D020317:Salmo salar / Q000002:abnormalities* / Q000276:immunology; D013122:Spinal Diseases / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D000267:Tissue Adhesions / Q000209:etiology / Q000662:veterinary
chemical_list: D001428:Bacterial Vaccines