Studies on Toxoplasmosis

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  • Department of Ophthalmology and Francis I. Proctor Foundation For Research in Ophthalmology, University of California School of Medicine, San Francisco


Toxoplasma-methylene-blue dye-test variation. Five serum samples from 20 subjects were tested for dye-test titer, the samples being drawn over a period of 16 days. This was repeated in another 20 subjects, each of whom was given one skintest dose of toxoplasmin before beginning the serum-withdrawal series.

In both series the dye-test titers remained remarkably constant for each individual, and did not change after the preceding injection of toxoplasmin. This work also established the repeatability of the serologic dye-test determination.

Chemotherapy of toxoplasmosis. Several antimalarial drugs were tested for effectiveness in prolonging the life of mice after infection with a highly lethal dose of Toxoplasma (RH strain). Oral or subcutaneous drug administrations were employed. None of these (Plaquenil, Aralen, and Primaquine) showed any effect.

Various sulfonamide compounds, both alone and in combination with pyrimethamine, were tested as drug cures. The most effective combinations were sulfapyrazine-pyrimethamine, and sulfadiazine-pyrimethamine mixtures, substantiating the work of Eyles and others. Another double-sulfa mixture (sulfamylon and sulfamerazine) was tested and also found to be very effective as a drug cure in acute toxoplasmosis, expecially when used with pyrimethamine. These experiments also demonstrated the synergism existing between certain sulfonamides and pyrimethamine against toxoplasmosis in mice.

Author Notes

Supported by a Summer Medical Student Grant from the National Council to Combat Blindness, Inc., and a Summer Medical Student Grant from The American Cyanamid Corporation, Lederle Division.