Direct development of enteroepithelial stages of Toxoplasma in the intestines of cats fed cysts.

Four newborn (1- to 2-day-old) and two weaned (55- to 67-day-old) Toxoplasma-free cats were killed between 23 and 120 hours after ingestion of Toxoplasma gondii cysts from the brains of infected mice, and the cats' tissues were examined for the development of Toxoplasma. Intraepithelial Toxoplasma types (B, C, and D) were found in sections of small intestine. Homogenates of mesenteric lymph nodes, spleen, and liver of each cat were injected intraperitoneally into each of six weaned Toxoplasma-free cats to test the hypothesis of extraintestinal pregametogonic stages, as proposed by Overdulve (1978). Of the six cats injected with infected feline tissues, none shed oocysts within 17 days. Thus, the hypothesis of extraintestinal pregametogonic stages was not confirmed.