RESUMEN
A method was designed to evaluate and compare the microtitration agglutination test (MAT) and the enzyme-linked immunosorbent assay (ELISA) to detect antibodies in swine sera to Treponema hyodysenteriae and thereby establish a method for determining the prevalence of swine dysentery (SD) in herds. According to sampling criteria based on the hypergeometric distribution, sera were collected from 3 age groups of swine from farms having a history of SD on the premises (SD+) recently or being free of the disease (SD-). The highest degree of test sensitivity was obtained when sera from market age swine were evaluated with the ELISA. Of 14 SD+ herds from which sera were obtained from market-age swine, 13 were positive with the ELISA (93%); none of the 8 SD- herds was positive. The detection rates of individual swine in the SD+ herds for the 2 tests by age group were as follows: MAT--adult swine 1.4%, market-age swine 6%, and weaned pigs 0.8%; ELISA--adult swine 16%, market swine 31%, and weaned pigs 0.5%.
Asunto(s)
Pruebas de Aglutinación/veterinaria , Disentería/veterinaria , Ensayo de Inmunoadsorción Enzimática , Técnicas para Inmunoenzimas , Enfermedades de los Porcinos/diagnóstico , Infecciones por Treponema/veterinaria , Factores de Edad , Animales , Anticuerpos Antibacterianos/análisis , Disentería/diagnóstico , Porcinos , Treponema/inmunología , Infecciones por Treponema/diagnósticoRESUMEN
The enzyme-linked immunosorbent assay (ELISA) was evaluated and compared with the microtitration agglutination test for the detection of swine antibody to Treponema hyodysenteriae lipopolysaccharide antigens. Cells of T. hyodysenteriae serotypes 1 and 2 were extracted with hot phenol-water (68 degrees C). The lipopolysaccharide fraction from the aqueous phase was coated on plastic wells at concentrations of 1 micrograms (serotype 1) and 10 micrograms (serotype 2) of carbohydrate per ml. The ELISA was serotype specific when lipopolysaccharide antigens were reacted against sera from convalescent swine. Seroconversion of infected pigs was detectable with the ELISA within 1 to 2 weeks postinoculation and with the microtitration agglutination test 2 to 3 weeks postinoculation. Antibody titers could be detected in convalescent pigs as long as 19 weeks postinoculation by the ELISA and 12 to 13 weeks postinoculation by the microtitration agglutination test. Therefore, the ELISA may be useful for the detection of asymptomatic carriers.