Standardization of an enzyme-linked immunosorbent assay (ELISA) for detection of antibodies anti-Corynebacterium pseudotuberculosis in sheep

Caseous lymphadenitis (CLA) is a contagious disease caused by Corynebacterium pseudotuberculosis. It occurs worldwide and is responsible for economic losses in sheep raising. The aim of this study was to standardize an indirect ELISA to detect antibodies anti-C. pseudotuberculosis in sheep. Serum samples from animals previously tested serially using microbiological culture and PCR from the puncture of lymph nodes and lungs, made up an initial panel with the aim of standardizing the test. When it was applied to field samples, the ELISA reaction showed sensitivity of 100% and specificity of 100% based on microbiological culture and PCR results. Although microbiological culture is the gold standard in C. pseudotuberculosis diagnosis, the ELISA standardized in this study seems to be advantageous because it is faster to process the samples, and may be used as a screening test, or even for animals trade, once the disease is often unapparent, making clinical and microbiological diagnosis difficult to be performed.