RESUMO
Although the incidence of false negative rose bengal plate test (RBPT) results on sera which were delayed in transit for one to 17 days was greater than 0.65%, up to 7.2% of such reactions occurred in one infected herd. Since no correlation between the incidence of false negative RBPT results and delay in sera in transit could be found, it was postulated that this type of reaction should be attributed to animals in the early incubation stage of the disease or to individual variation in the rate of response to the RBPT; a problem which should resolve itself during consecutive tests. Blood samples taken from herds to be sold at sales or public auctions, however, should all be tested by the complement fixation test. No correlation between the serum agglutination test and complement fixation test results were noted except where serum agglutination test titres exceeded 134 IU ml-1.
