Relationship between acquired resistance, portal hypertension, and lung granulomas in ten strains of mice infected with Schistosoma mansoni.

Pronounced differences in resistance to reinfection and pathology were observed among various strains of mice infected with Schistosoma mansoni. When comparing strains, the level of resistance induced by a 12-week infection correlated closely with the degree of portal blood pressure elevation and number of lung egg granulomas, but did not correlate with other pathological parameters or with the number of worms or tissue eggs. Among individual mice of the same strain, however, resistance was proportional to the number of worms and tissue eggs. Nmri strain mice infected for more than a year remained highly resistant to reinfection and continued to shunt eggs into the lungs, but showed considerable resolution of portal hypertension, hepatomegaly and splenomegaly. No association was observed among mouse strains between the mortality resulting from a primary infection and the severity of any of the pathological parameters which were measured.