A strain of toxoplasma recovered from the brain of a fatal case of congenital toxoplasmosis was studied and its biologic properties recorded. The strain was pathogenic for mice, rabbits, guinea pigs, hamsters, cotton rats and white rats. It was weakly pathogenic for young chicks. Immunologically it showed good cross immunity and good cross neutralization with a known (R.H.) strain of toxoplasma. No evidence was obtained for infection in three wild rats caught in the vicinity of the patient's home.
From the Children's Hospital and the Departments of Bacteriology and Pathology, University of Cincinnati, College of Medicine.