[Tick bite and Lyme borreliosis : an epidemiologic study in the Erlangen area]

BACKGROUND: Lyme borreliosis is transmitted by tick bites. Approximately every fifth local tick (Ixodes ricinus) is infected. Transmission, therefore does not occur with every bite, and disease doesn't always follow infection. The goal of the study was to investigate the risks of infection and disease after tick bites in the area of Erlangen/Germany. METHODS: Between April 1989 and October 1991 seventy-one of our out-patients (30 females, 41 males) aged 6 months to 29 years had a tick bite and were enrolled into the study. After the ticks had been removed, a blood specimen for a specific Borrelia burgdorferi antibody assay (IFT) was collected. An interview by phone was performed 4 weeks later and an appointment for a second blood collection was arranged. RESULTS: In 69 patients the initial titer was negative, in two patients it was 1:32. Sixty patients could be reached by phone, and in 43 a second blood sample was available. There was seroconversion detectable in 4 instances, two of whom were asymptomatic, one had unspecific symptoms and one developed lymphocytoma. There were no manifestations of late stage disease in the study population. CONCLUSION: These results confirm the current recommendation of the Bundesgesundheitsamt (German Federal Health Institute) that generally antibiotic treatment after a tick bite is not necessary.