COMPARISON OF A COMPLEMENT-FIXATION TEST, A GEL-DIFFUSION TEST AND 2 ABSORBED AND UNABSORBED ELISAS FOR THE DIAGNOSIS OF PARATUBERCULOSIS IN SHEEP

A complement fixation test for paratuberculosis, a gel diffusion test and two enzyme-linked immunosorbent assays (ELISA) were evaluated usin g sera from Mycobacterium paratuberculosis infected and non-infected s heep. Gross pathology and histopathology were used as parameters of in fection. The two ELISAs, one of which is commercially available for te sting cattle, were used before and after sera had been absorbed with a soluble sonicate of Mycobacterium phlei. Differences between the vari ous tests and between ELISAs before and after absorption were nonsigni ficant (P>0.05) in non-infected sheep or in animals with gross or hist opathological lesions. The specificity of all the tests was at least 9 7%. Sensitivity in histopathologically positive sheep was at least 98% . Sheep from infected flocks but without histopathological lesions sho wed serological results which were poorly correlated between the vario us tests.