Latent bovine brucellosis.

Adult cattle in a herd suffering from widespread infection with Brucella abortus biotype 2 were slaughtered during the eradication campaign. A heifer calf fom that herd was moved to a fresh herd which remained apparently free from brucellosis until nine years later when the same animal produced a strongly positive serological reaction and Brucella abortus biotype 2 was isolated from its milk.