[Animal foci and transmission routes of Toxoplasma gondii]

In the transmission of T. gondii from animal sources to man a major part is played by animal tissues containing toxoplasmatic cysts and toxoplasmatic oocysts which result from the sexual reproduction of the parasites in the small intestine of feline animals. Tachyzoits play a minor role in the development of toxoplasmosis in man, most frequently when animals, their tissues and secretions are handled in the stage of parasitaemia. As to domestic animals, rabbits and sheep are infected most frequently and to a very small extent cattle. Animals from small farms are infected more frequently as there is a greater chance of contact with the domestic cat. A natural reservoir of T. gondii are small terrestrial mammals where intrauterine transmission occurs and the infection passes from one generation to the next. Thus elimination of the parasites in animal sources is not feasible and in prevention of toxoplasmosis attention must be focused primarily on transmission of T. gondii from known animal sources to man.