Disease in sea urchin Strongylocentrotus purpuratus: experimental infection and bacterial virulence

Abstract

Naturally occurring diseased sea urchins Strongylocentrotus plupuratus were present at low incidences in the Monterey Bay area, California (USA); they were used to examine the basic characteristics of disease in sea urchins. Bacteriological sampling of lesion material revealed the presence of 14 bacterial strains including Vibrio, Aerornonas, Flavobaderiurn and Pseudornonas. The 14 isolates were characterized and extensively tested for pathogenic potential. Of these bacterial isolates, only those of Vibrio anguillarurn and Aeromonas salrnonicida were able to initiate lesion formation in the laboratory. Experimental lesions induced in the laboratory had similar characteristicsand progression of events as those observed during naturally occurring spontaneous infections. Experimental infectivity tests determined that a stress such as injury was necessary for the formation of a characteristic lesion.