Seroepidemiological Evidence that Shearing Wounds are Mainly Responsible for Corynebacterium pseudotuberculosis Infection in Sheep

Anti-Corynebacterium pseudotuberculosis toxin titers were examined by an enzyme-linked immunosorbent assay (ELISA) at 3 to 5 month intervals in sheep of three age groups (lambs, 1- and 2-year-old sheep). A significant increase in the ELISA-positive ratio was found only in July, 3 months after shearing, in 1- and 2-year-old sheep. A decrease in the positive ratio was found in the same month in lambs, possibly due to a decrease in maternal antibodies. Since the 1- and 2-year-old sheep had been sheared in April, it was considered that the increase in the positive ratio in July might be closely related to the shearing in April.