Antibodies to Borrelia spirochetes in sera from Swedish cattle and sheep.

In the southern parts of Sweden a Borrelia infection transmitted by the tick Ixodes ricinus may affect man, In the present study antibodies to Borrelia spirochetes were studied in sera from 58 cows, 68 calves and 13 lambs from areas in southern Sweden where Ixodes ricinus occurs. For comparison, serologic studies were also performed on 88 cows and 10 lambs from the northern parts of Sweden. Serum titers of > 80 were found in 14 of the calves and 23 of the cows from southern Sweden but in only 1 of the cows from northern Sweden. In 11 of the lambs from the south a serum titer of > 40 developed. None of the lambs from the north had a serum titer of > 40. The results indicate that cattle and sheep in certain areas of Sweden are exposed to Ixodes ricinus-borne Borrelia spirochetes. In 9 of the lambs from southern Sweden: an endemically occurring arthritis had developed. The possibility that this arthritis may be caused by Borrelia spirochetes is discussed.