Congenital transmission of toxoplasmosis through successive generations of mice.

CONGENITAL transmission of infectious agents—viruses, rickettsiae, spirochaetes and piroplasms—is not uncommon in arthropods and may pass through many generations. It is much less common in mammals in which, when it occurs, it usually stops at the second generation. In mice, however, the virus of lymphocytic chorio-meningitis can be transmitted indefinitely1, and there are claims that in man syphilis can pass to the third generation2.