TWENTY-THIRD ANNUAL EASTERN FISH HEALTH WORKSHOP JOHN CARVER INN, PLYMOUTH, MA 30 MARCH - 2 APRIL, 1998 A Vibrio Challenge Model To Test The Impact Of Water Quality On Disease Susceptibility In Shrimp T.M. Mikulski, L.E. Burnett and K.G. Burnett University of Charleston, Charleston, S.C. *Medical University of South Carolina, Charleston, S.C. The production of reactive oxygen intermediates (ROIs) by phagocytes as measured in vitro during the respiratory burst can vary with changes in water pH, CO2 and O2 in both vertebrates and invertebrates. We are developing a challenge model to test the importance of changes in these same water quality parameters on disease susceptibility in whole organisms. Grass shrimp, Palaemonestes pugio, were collected from local tidal creeks and allowed to acclimate to test conditions in the laboratory. Animals (2.1 - 3.4 cm) were injected intramuscularly with varying doses of a known pathogenic strain of Vibrio parahaemolyticus. The shrimp were challenged under ambient oxygen conditions (140-150 Torr) in filtered artificial seawater kept at 30ppt. The 96hr LD50 ranged from 9.672 x 104 to 2.144 x 105 colony forming units/shrimp. Animals injected with LD50 doses of V. parahaemolyticus and held under moderate hypoxia (45 Torr) displayed lower 96hr survival (11%) than animals held in normoxia (50%). This challenge model is now being extended to juvenile and adult shrimp of commercial interest, including Penaeus vannamei and P. setiferus.   Return to 23rd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page