An ELISA was developed using an SDS extract of Brucella abortus as antigen to detect antibodies in cattle sera. The antigen was stable at 4 °C for at least 4 years and although it gave optimal results at a 1/4 000 dilution it could detect reactors at a 1/32 000 dilution. Based on comparative CF tests on 430 sera from negative herds and 187 sera from positive herds a reading of 0,07 or less using a 492 nm filter could be considered a negative reaction. The ELISA could be a useful test to supplement the CF test but further evaluation is still required.
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