Seasonal Distribution of Chondrococcus columnaris Infection in River Fishes as Determined by Specific Agglutinins

Abstract

River fish populations infected with Chondrococcus columnaris disease were surveyed by measurements of C. columnaris agglutinating antibodies in blood sera of fishes and by isolation of the pathogen using microbiological plating methods. Agglutinins were demonstrated in all 13 fish species collected except whitefish (Prosopium williamsoni). Blood serum from samples of fishes at four Columbia River sites during 1965 and three Columbia River sites and one Snake River site during 1969–70 demonstrated single annual cycles of C. columnaris antibody production. During the two annual sampling periods, the magnitude of antibody titers and frequency of fish with agglutinins increased in warm water and declined in cool water. The rise in titers occurred after a winter low, and usually followed the period when the first C. columnaris organisms were isolated from native fish. Agglutinating titers up to 1:5000 were found but most peak titers were between 1:320 and 1:640.