Serological detection of Trichinella spiralis in swine by ELISA (enzyme-linked immunosorbent assay) using an excretory-secretory (E/S) antigen.

The enzyme-linked immunosorbent assay (ELISA) method is recommended for farm surveillance programs and may be useful for epidemiological studies in wildlife or for establishing Trichinella-free areas. In this study, our interest was to compare the specificity and the time of seroconversion of excretory-secretory (E/S) antigens prepared from Trichinella spiralis. A group of eight pigs was inoculated with 500 T. spiralis larvae per animal, and blood sampling was performed at 3 and 4-day intervals during all experiments. The numbers of muscle larvae were determined in four different muscles groups. The larvae per gram burden shows that the most heavily parasitized muscles were the diaphragm [mean = 43.7 larvae per gram (lpg)] and the tongue (mean = 16.9 lpg). Antibody responses were detected by any of eight infected pigs of T. spiralis. Using the ELISA method with E/S antigen, antibodies to T. spiralis were first found on the day 21st p.i. The initial detection of antibodies varied from 21st to 31st day p.i., and the peak was reported 42nd day p.i. Dynamic of antibodies was stable or increased slightly throughout the experimental period (60 days post-inoculation). Our results represent important data for validation of a serological test, especially if blood samples are taken during early stages of infection.