DIAGNOSIS OF TRICHINOSIS IN SWINE BY ENZYME-IMMUNOASSAY, USING A SYNTHETIC GLYCAN ANTIGEN

Objective-To assess performance of a synthetic carbohydrate antigen fo r use in an enzyme immunoassay for diagnosis of trichinellosis in swin e. Animals and Sample Population-47 York x Duroc pigs and field sera f rom 265 farm pigs raised under various management systems. Procedures- Each of 47 pigs was inoculated with 25 to 500 Trichinella spiralis lar vae, and blood samples were obtained weekly. At postinoculation week 1 2, pigs were euthanatized, and tissues recovered from the tongue and d iaphragm were digested to determine worm burden. Serum samples from ex perimentally infected pigs and sera obtained from pigs on a farm were tested by enzyme immunoassay, using standard excretory-secretory and s ynthetic glycan antigens. Results-Of the 47 pigs, 46 (97.8%), with wor m burden ranging from 0.02 to 248.8 larvae/g of tissue in the tongue a nd diaphragm, tested seropositive using both antigens. Time of serocon version varied among pigs and was negatively correlated with intensity of infection. Minor differences were observed in time of seroconversi on between the 2 antigens in 11 of 46 pigs, suggesting some difference s in the antibody response. One pig with a worm burden of 0.01 larva/g was not detected by enzyme immunoassay using either antigen. Backgrou nd values obtained using the 2 antigens did not differ among confineme nt-raised pigs, but background values for pigs raised outdoors on dirt lots were significantly lower using the glycan antigen. Low-level, na turally acquired T spiralis infections in pigs were detected in most i nstances by use of both antigens, although there were some differences in antibody responses of infected pigs. Conclusion-The synthetic glyc an antigen has potential for replacing excretory-secretory antigens as a standardized reagent for diagnosis of trichinellosis in pigs.