Within minutes of a traumatic stressor, several plasma proteins increase in concentration. Molluscan schistosomiasis . Strains of snail that are constitutively resistant and others that are susceptible to Schistosoma mansoni help us address questions dealing with the basis for these differences, and with mechanisms exploited by the parasite in survival under immunologically hostile conditions. Oxygen-dependent cytotoxic pathways have been found to play a major role in the host's ability to kill parasites. Strategies used by the parasite include antigenic disguise either by mimicking host antigens or by acquiring them from host blood.
Schistosomes also secrete factors that interfere with host snail leukocyte functions.
The host's blood interacts with the parasite in a variety of ways, both nourishing it and threatening its survival. Complex carbohydrates are central to these interactions. We are characterizing such events at the macromolecular level. The immediate effects of acute stress on innate defenses in rainbow trout. Saunders, London, in press.