Immunohistochemical identification of Vibrio salmonicida in stored tissues of Atlantic salmon Salmo salar from the first known outbreak of cold-water vibriosis ('Hitra disease')

Abstract

Immunohistochemistry based on the avidin-biotin complex method was employed to identify Vibrio salmonicida or its products, in formalin-fixed, paraffin-embedded tissue specimens from Atlantic salmon Salmo salar L. suffering from experimentally induced cold-water vibriosis. The technique was also used to establish the presence of the bacterium in stored tissue specimens collected in 1977 during the first known outbreak of the disease in Norway. Antigens of V. salmonicida were specifically identified in tissue specimens from heart, liver, spleen, kidney, and gut by incubation with monoclonal antibodies specific for the bacterium. These findings offer strong evidence for V. salmonicida as the causative agent in the first outbreak of the disease, and are consistent with other reports identifying it as the aetiologic agent of cold-water vibriosis.