Use of an ELISA for serodiagnosis of parasitic bronchitis in cattle

The enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of parasitic bronchitis in cattle was evaluated in naturally injected, experimentally infected and vaccinated animals. Significant antibody titres could be demonstrated from five weeks after animals had been exposed to the parasite, so that infected animals could be identified during the summer. The test did not give false positive results in vaccinated animals. The technique proved particularly useful in revealing latent infections in milking herds in the autumn when heavy burdens of worms in the lungs do not generate any larvae in the faeces.