Flocculation Test in Sera from Hogs Experimentally and Naturally Infected with Trichinella spiralis

Abstract

Four experiments were conducted to determine whether or not infections with Trichinella spiralis in hogs can be detected by the floccuiation test at the time the animals are slaughtered at the abbatoirs. Eighteen hogs were reared and infected under controlled experimental conditions, and 74 were reared under natural conditions. All sera were tested by the bentonite flocculation test. The sera of some animals were also tested with a 2nd antigen made by adsorbing the acid soluble fraction of Melcher''s purified antigen onto bentonite. The flocculation test was quite reliable in detecting heavy infections of T. spiralis in swine if the serum was obtained a few weeks after ingestion of infected meat. On the other hand, when the infection was light or when the serum was obtained before the 2d week from ingestion of larvae, the reaction failed to reveal the presence of infection. When infections were somewhat heavier, all animals that had become positive reverted to a negative serology after several weeks. For these reasons, the practicability of employing the flocculation test for the routine diagnosis of infected hogs at the time they are slaughtered at the abattoirs is very definitely limited.