Tick-borne Borrelia infection in patients with Bell's palsy.

An enzyme-linked immunosorbent assay was applied to serum samples of 94 patients diagnosed as having Bell's palsy: they were studied throughout two consecutive years in an attempt to establish serologic evidence of a tick-borne spirochetal infection. A strain of Borrelia spirochetes, isolated from Swedish Ixodes ricinus ticks, was used as an antigen, and separate estimations of spirochetal IgG and IgM antibodies were made; serum samples with titers above the 95th-percentile level of 120 healthy individuals were considered positive. Thirteen percent of the patients' serum samples were IgG-positive, 3% were positive for IgM, and 3% were positive for both IgG and IgM. A twofold or greater increase of IgG titers was found in 6%. All the patients who were seropositive experienced the onset of palsy during the period from July to December.