Applying immunoperoxidase and Antigen-Capture ELISA methods for rapidly diagnosing infectious bursal disease.

摘要

The aim of the study was to compare immunoperoxidase (IP) and Antigen-Capture ELISA (AC-ELISA) tests in detecting infectious bursal disease virus (IBDV) in the Fabricius Bursa (BF) of infected chickens. BFs were collected at 3 days p.i. with IBDVs of low pathogenicity (isolated from a mild form of IBD) and very virulent pathogenicity (isolated from an acute form of IBD) at 1, 3, 6 and 9 days p.i. with vaccinal, low pathogenic and very virulent strains. BFs from broiler chickens suspected of having IBD were also used. BFs were cut into frozen histological sections and, after fixing with formaldehyde, were stained using the IP method. The remainder of BFs was used in AC-ELISA after homogenization and clarification. The sensitivity and specificity of both tests in detecting IBDV antigens were comparable but the amount of viral antigen could be determined only by using the AC-ELISA method. The intensity of reaction and the time during which the viral antigen was detected were strongly correlated with the pathogenicity of the IBDV strain being used. Inoculation with the vaccine strain yielded positive results only on day 6 p.i. and the amount of detectable antigen was very low. Infection with the low pathogenic Polish strain produced more antigens and was detectable from days 1 to 6 p.i. The antigen of the very virulent strain was found in the highest amount and could be detected for 9 days beginning on day 1 p.i. The study indicated that the IP method is simple, rapid and less laborious than AC-ELISA. However, AC-ELISA is more useful because it also measures the amount of detected antigen in a specimen..