Lyme disease in Japan. Analysis of Borrelia species using rRNA gene restriction fragment length polymorphism.

BACKGROUND

Lyme disease is sporadically observed in Japan since the first report in 1987. We have experienced 19 cases of Lyme disease. In 12 out of 13 trials we succeeded in isolating Borrelia strains (JEM1-12) from erythema migrans (EM) lesions. Recently, Borrelia burgdorferi sensu lato was classified into at least three distinct subgroups, B. burgdorferi sensu stricto, B. garinii and B. afzelii.

OBJECTIVE

In order to characterize Lyme disease in Japan, we summarized the clinical features of our cases and investigated the nature of the isolated Borrelia strains.

METHODS

The 12 Borrelia strains were analyzed by restriction fragment length polymorphism (RFLP) of ribosomal RNA gene.

RESULTS

Most of our 19 patients were in stage I with EM as the main clinical manifestation. RFLP analysis using 12 strains isolated from the patients indicated that 8 strains (group IV, V) were different from the three aforementioned genospecies.

CONCLUSION

Clinical data from the present study substantiate the view that Japanese Lyme disease has a relatively milder course. We speculate that this may be related to the specific Borrelia strains in Japan.