G.S. Traxler, BSc; M.F. Li, PhD
Fisheries Research Board of Canada, Halifax Laboratory, Halifax, Nova Scotia, Canada
An abscess in the nasal region of a cod fish, held for experimental work, resulted in a large swelling; the excessive amount of purulent exudate filled the nostrils. Among the signs of distress was an apparent lack of equilibrium.
Histological examination of the nasal area showed extensive destruction of the muscle and connective tissue as well as an infiltration of leucocytes as pathological signs.
A total of six microorganisms were isolated from the infected region. The suspected pathogen was classified as a Vibrio; among the other isolates, felt to be secondary invaders or bacteria normally present in sea water were, Achromobacter and Flavobacterium species. Salt enriched medium was required for growth of three of the isolates. All of the isolates failed to grow at 37°C, the optimum temperature for growth was 15-20°C.
Pathogenicity tests were performed using Fundulus heteroclitus as the test organism. Intramuscular injection of the suspected pathogen caused discoloration and destruction of the tissue surrounding the injection site similar to the originally observed pathological condition.