EXPERIMENTAL SCHISTOSOMA-BOVIS INFECTION IN GOATS - THE INFLAMMATORY RESPONSE IN THE SMALL-INTESTINE AND LIVER IN VARIOUS PHASES OF INFECTION AND REINFECTION

In a histopathological study of goats experimentally infected with Sch istosoma bovis, the characteristics of the inflammatory response in th e small intestine and liver related to tissue egg counts and fecal egg excretion were compared between goats at different time periods of pr imary infection and of primary infection followed by challenge. At ear ly patency, coinciding with increasing egg excretion, the intestinal l amina. propria showed numerous intact schistosome eggs devoid of any i nflammatory reaction, whereas egg-associated inflammatory foci in the intestine were significantly few. Later in primary infection and after challenge, intestinal changes were marked by a granulomatous anti-egg response, with only a minor component of eggs lacking inflammatory ch ange, and were consistent with a reduction of egg transfer into the gu t wall. Hepatocellular necrosis with eosinophil infiltration was prono unced only during the early patent stage. The results indicate that th e early cascade of fecal egg excretion in caprine schistosomosis bovis is aided by a low degree of tissue reactivity to eggs in the intestin e. They also lend support to previous findings indicating that an anti -fecundity effect is operative after exposure to challenge in this par asitic infection in goats.