EPIDEMIOLOGICAL STUDY ON LYME DISEASE IN THE FAR EASTERN COUNTRY

我们对我国北方、长江流域和韩国的媒介蜱和水库动物进行了莱姆病疏螺旋体调查。通过5S-23 SrRNA基因间隔区和鞭毛蛋白基因PCR-RFLP分析及序列分析，将采集自中国北方和俄罗斯远东地区的全沟硬蜱分离株鉴定为B.afzelii或B. garinii。B.garinii产生的RFLP模式C在日本很常见，但在欧洲没有，是这些地区的优势种。此外，从韩国中部采集的日本I.nipponensis分离株被鉴定为远东型B.garinii或B. afzelii。从韩国获得的日本硬蜱分离物暂时被描述为阿氏B. afzelii相关组，其特征在于基因间隔区和16 SrRNA序列。这些分离物与欧洲的野蓖麻B.valaisiana分离物和日本的柱状野豌豆Am 501菌株具有较高的相似性。从长江流域采集的黑线姬鼠和家鼠中分离的分离株分别鉴定为阿氏B. afzelii相关群和新基因型。另外，从该地区卵形硬蜱分离到的一个分离物也表现出与家鼠分离物相同的特征。对新发现的种进行了进一步的研究，根据外表面蛋白A、B和C基因序列的系统发育分析，提出了B.garinii和B.afzelii在日本和欧洲之间通过远东国家，如俄罗斯远东、中国北方和韩国传播的可能性。

We made Lyme disease borrelia survey of vector ticks and resevoir animals in Northern part of China and the Yangtze River valley, and Korea. Borrelia isolates from these sources and from far eastern Russia we got previously were analyzed by 5S-23S rRNA intergenic spacer and flagellin gene PCR-RFLP analysis and sequence analysis.Isolates from Ixodes persulcatus collected Northern China and far eastern Russia were identified as B.afzelii or B.garinii. B.garinii generate RFLP pattern C which is commonly found in Japan but not in Europe were dominant species in these area. Furthermore, isolates from I.nipponensis collected in central Korea were identified as B.garinii of far eastern type or B.afzelii. Isolates from I.nipponensis tentatively described as B.afzelii-related group obtained from Korean researcher were characterized on intergenic spacer and 16SrRNA sequences. These isolates showed relatively higher similarity values to B.valaisiana isolated from I.ricinus in Europe and strain Am501 from I.columnae in Japan. Isolates from Apodemus spp.and Rattus spp.captured in the Yangtze River valley were identified as B.afzelii-related group and new genotype, respectively. Also, one isolate from I.ovatus in the area showed the same feature to those from the Rattus spp. Further study to described new species is undertaken.By the phylogenetic analysis based on the sequence of outer surface protein A,B,and C,genes, transmission of B.garinii and B.afzelii between Japan and Europe via far eastern country, such as far east Russia, northern China, and Korea was suggested.