Investigaciones sobre toxoplasmosis

Abstract

The author succeeded in isolating 10 strains of Toxoplasma gondii (50 percent) by means of individual passages through 20 white mice of an emulsion of the brains of 20 ravens of the species Coragyps atratus foetens. The emulsion was administered intraperitoneally. This result proves that a hitherto unknown host is highly susceptible to chronic toxoplasmosis. This is the first observation of this agent in feral birds in Argentina. By feeding white mice with milk obtained by milking a bitch, a cat, and a goat which had been experimentally infected with toxoplasma, it was conclusively proved that the parasite is eliminated through the milk which killed almost all the mice that ingested it. It is believed that females in milk eliminate more toxoplasma during the period of acute infection owing to the higher degree of parasitemia so that transmission is easier during that period. By administering to cockaroaches Periplaneta americana, via the digestive route, one drop of ascitic liquid extracted from white mice affected with toxoplasmosis, it was possible to show that, through inoculations of the trituration of the insects into mice, T. gondii survives at least 65 days in the organism of the arthropod. Infection by the digestive route was shown to be possible when the disease was transmitted to white mice by feeding them with a trituration of cockroaches which had been experimentally