Abstract: A total of 94 mice were experimentally infected with Trichinella spiralis larvae, and circulating antigens in their sera were determined at different periods after infection with ELISA double sandwich method, Some infected mice began to show positive reaction 3 days after inoculation and the reaction became strongly positive in all infected animals 30 days post-infection. The percentage of positive reaction and the value of OD in ELISA tended to increase with the increase in intensity and duration of infection, One week after being treated with albendaole, the larvae within the muscles of the infected animals were mostly found dead and some of them appeared to be absorbed by the surrounding tissue, but the reaction still remained 100% positive. However, at 2,3 and 4 weeks after treatment, the percentage of ELISA positives became 60%, 20% and 10%. On the contrary, specific seral antibody titre remained high. It indicates that circulating antigens may differenciate between acute and past infections. Dot-ELISA and reversed indirect hemagglutination were also conducted simultaueously. The positive rates of Sendwich ELISA, Dot-ELISA and RIHA were 76.9%, 56.9% and 33.8% respectively. All control animals showed negative reaction.

Key words: Trichinella spiralis, circulating antigen, ELISA double sandwich method, reversed indirct hemagglutination, Dot-ELISA, larvae soluble antigen, excretory-secretory antigen