A total of 16 injections of normal rhesus-monkey erythrocyte stromata (0.0625 mg N per injection) and hemolysate (0.0212 mg N per injection) were administered to each of three groups of mice, -30 to -1, +1 to +30, and +31 to +60 days after infection by Puerto Rico strain Schistosoma mansoni cercariae. Mice were killed on days 61 to 66 after infection, and parasitemia and hepatic pathology were determined. Mice receiving injections of stromata +31 to +60 days after infection were devoid of schistosomes and schistosome eggs, and macro- and microhistology of the liver was normal. All other infected groups were consistent with control infections. The mechanism involved is undefined, but a sudden, overwhelming host response to the schistosome infection is suggested.
Present address: Tropical Disease Center, St. Clare's Hospital, 415 West 51st Street, New York, New York 10019.