Invasion of the Extra-intestinal Organs of Cats by the Merozoites and Zoites of Isospora rivolta

Abstract

The possibility of invasion of the extra-intestinal organs of cats by the merozoites and zoites of Isospora rivolta were examined. Four cats (donor) given the organs of mice that had been inoculated with 2.3×10^5 oocysts were necropsied 3 days thereafter. Numerous merozoites in their small intestines and a few zoites in the mesenteric lymph nodes were found. Their intestinal mucosa and extraintestinal organs (liver, mesenteric lymph nodes and spleen) were separated and fed to 2 recipient cats (the 1 st recipient), respectively. The 1 st recipient cats were sacrificed on day 9 and the extra-intestinal organs of each group were fed to other cats (the 2 nd recipient). Both of 2 nd recipients began to shed oocysts from 7 or 9 days after feeding. A greate number of merozoites in donor cats were inoculated into 1 st recipients, whereas the 2 nd recipient shed few oocysts. This result indicate that a few merozoites and zoites may invade the extra-intestinal organs of the 1 st recipient cats.