Antibodies to Borrelia burgdorferi in New England horses: serologic survey.

Twelve of 50 randomly selected horses from areas endemic for Borrelia burgdorferi had indirect fluorescent antibody titers of 1:8 to 1:2,048 against B burgdorferi. One of 50 horses from nonendemic areas had a titer of 1:8. This difference in the number of horses seropositive for B burgdorferi (P less than 0.002) and our finding that seropositive horses did not have agglutinating antibodies against potentially cross-reacting Leptospira spp indicated that horses in endemic areas were exposed to B burgdorferi and that the spirochete induced an antibody response in the horses.

Arthritis caused by Borrelia burgdorferi in dogs.

From October 1982 to May 1984, we studied 34 dogs from the Lyme, Conn area that had a history of tick exposure and lameness associated with pain, warmth, and/or swelling in one or more joints. Large numbers of polymorphonuclear leukocytes were seen in Giemsa-stained smears of synovial fluid from 9 dogs, and spirochetes (Borrelia burgdorferi) were found in 1 sample by darkfield microscopy and immunoperoxidase techniques. The geometric mean antibody titer to B burgdorferi in the 34 dogs was 1:2,700, compared with 1:285 in 43 clinically normal dogs from the same area (P less than 0.0001) and 1:50 in 29 dogs from an area in New Jersey that is not endemic for human Lyme disease (P less than 0.00001). We concluded that B burgdorferi in dogs may cause arthritis similar to that in human Lyme disease.