Corynebacterium pseudotuberculosis infection in goats. IV. Course of the infection in two recently infected goat herds.

Adult animals from 2 herds were examined clinically and serologically, 5 (Herd A) and 4 (Herd B) times during the same period of 3% years. Serum samples were examined for antibodies against Gorynebac-terium pseudotuberculosis using the bacterial agglutination test (BAT) and the hemolysis inhibition test (HIT). The results of the first examination showed that no animal in Herd A was seropositive, while in Herd B 1 animal showed a high positive titre in BAT. The prevalence of animals with superficial swellings was then Herd A and 4 in Herd B. In both herds, the prevalence of animals with superficial swellings and seropositive reactions increased during the following 1–2 yeairs. About 30 % of animals had superficial lesions and close to 100 % were seropositive. The proportion, of animals with superficial swellings and seropositive reactions was almost constant on subsequent examinations. In some of the animals, superficial swellings were found during 2 or more of the examinations, a few animals having such lesions at the same site on both or all occasions. Animals in Herd A became infected through grazing together with goats from infected herds. Caseous lymphadenitis was introduced into Herd B by animals obtained from infected herds.