LYME-DISEASE SPIROCHETES IN TICKS FROM NORTHEASTERN CHINA

During May 1996, field surveys on Lyme disease spirochetes were conduc ted in Beijing, Shenyang, Fushun, and Inner Mongolia in northeastern C hina. The ticks collected consisted of 3 genera and 12 species. Of the se, Ixodes persulcatus was dominant in sun-exposed vegetation in fores ts in Inner Mongolia; 57 Borrelia strains (55/123 unfed adults and 2/5 immature stages fed on a rodent) were obtained from this tick by BSK culture. Additionally, 2/2 Apodemus peninsulae were positive. Ixodes n ipponensis, Ixodes pavlovskyi, Haemaphysalis douglasi, and Haemaphysal is megaspinosa, newly recorded in China, and other Haemaphysalis spp. were all negative for Borrelia. Based on a polymerase chain reaction-r estriction fragment length polymorphism analysis of the 45 strains suc cessfully subcultured, these were classified as 29 Borrelia garinii an d 16 Borrelia afzelii. These strains seemed to be more closely related to Japanese strains in genetic features than to those from Europe. Th e result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggested more diversity in both genospecies, but Borrelia burgdorferi sensu stricto was not found.