COMPARISON OF THE ABSORBED ELISA AND AGAR-GEL IMMUNODIFFUSION TEST WITH CLINICOPATHOLOGICAL FINDING IN-OVINE CLINICAL PARATUBERCULOSIS

Thirty-two sheep with clinical paratuberculosis and 53 normal, healthy control animals Here tested for serum antibodies to Mycobacterium avi um subspecies paratuberculosis with the absorbed enzyme-linked immunos orbent assay (ELISA) and agar gel immunodiffusion (AGID) test. All the sheep were necropsied and the diseased cases were categorised as havi ng either multibacillary ('lepromatous') or paucibacillary ('tuberculo id') intestinal lesions. The ELISA and AGID test were highly sensitive when testing the multibacillary group (86.4 per cent and 100 per cent , respectively) but the sensitivity of the tests in the paucibacillary group has significantly lower (10 to 50 per cent and 30 per cent, res pectively). These finding vr ere related to the ELISA optical density readings, with the multibacillary samples hating values significantly greater than those of the paucibacillary and control groups, and the o ptical density values appearing to correlate with the numbers of mycob acteria present in the intestinal lesions, These results indicate both the usefulness of serological testing in the diagnosis of the multiba cillary form of paratuberculosis and the difficulty in identifying ani mals with the paucibacillary form of the disease.