A serological survey of leptospirosis in sheep in Chile.

In order to investigate exposure to Leptospira spp. in sheep in the Xth Region in the south of Chile, 629 ovine serum samples were collected from 11 convenience selected sheep farms, using within farm random sampling. The sera collected were examined for antibodies to the following serovars; icterohaemorrhagiae, autumnalis, hardjo, pomona, ballum, and canicola, using the Microscopic Agglutination Test. Ten out of eleven flocks had sheep which were seropositive for at least one Leptospira spp. Positive tests, the majority at low titres, were obtained from 36/629 (5.7%) of all the serum samples tested. The most frequently detected serovars were, in descending order: icterohaemorrhagiae, autumnalis and hardjo. The greatest proportion of positive samples came from sheep which were over 30 months old.