Molecular epidemiology of Borrelia burgdorferi sensu lato in the East Asia.

1996年至1998年，我们在俄罗斯远东地区、中国和韩国进行了从蜱和野生啮齿动物中分离伯氏螺旋体的调查。通过各种分子分型方法和测序分析对这些分离株进行了鉴定。在中国东北和俄罗斯远东地区，过角伊蚊是主要媒介，携带阿氏贝氏杆菌和加里尼贝氏杆菌。该地区优势种为远东型，在欧洲未发现，与日本北海道和韩国北部分布相似。这一发现表明伯氏疏螺旋体在日本、俄罗斯远东地区和中国东北地区之间传播。然而，应该指出一个区别；在韩国北部地区，日本依蚊具有传播阿兹利布氏杆菌和加里尼布氏杆菌的能力。有趣的是，从朝鲜半岛南端收集的蜱中分离出来的菌株被鉴定为瓦莱西亚蜱。在长江流域的华南地区，疏螺旋体主要分离自细粒姬鼠、卵形姬鼠、黑线姬鼠和尼维文特姬鼠。大部分分离株鉴定为瓦莱西芽孢杆菌，与韩国的分离株相似。然而，与欧洲瓦莱西布氏疏螺旋体相比，伯氏疏螺旋体类群具有不同的ospA类型，表明伯氏疏螺旋体具有分化性。此外，四川和安徽分离的疏螺旋体具有独特的16S rRNA基因序列，相似度在99.8 ~ 100%之间，在系统发育树上具有聚类性，但与莱姆病疏螺旋体的相似度均小于99.0。因此，我们推测在欧洲蓖麻蜱中发现的瓦莱西布氏蜱可能适应于中国中部的细粒蜱、韩国南部的日本蜱和日本的圆柱蜱。此外，中国中部地区还存在独特的疏螺旋体。

We conducted a survey to isolate Borrelia from ticks and wild rodents in far eastern Russia, China, and Korea between 1996 and 1998. These isolates were characterized and identified by various molecular typing methods and sequencing analysis. In northeastern China and far eastern Russia, Ixodes persulcatus was a prominent vector and carried B. afzelii and B. garinii. The far eastern type of B. garinii was the dominant species in this area but was not found in Europe, similar to the distribution seen in Hokkaido, Japan and northern part of the South Korea. The finding indicate the transmission of Borrelia between Japan, and far eastern Russia and northeastern China. However, one difference should be point out ; in northern part of South Korea, I. nipponensis has the ability to transmit B. afzelii and B. garinii. Interestingly, isolates from the ticks collected in the southern tip of the Korean Peninsula were identified as B. valaisiana.In southern China beside the Yangze river valley, Borrelia was isolated from I. granulatus, I. ovatus, and Apodemus agrarius and Niviventer species. Most isolates were identified as B. valaisiana and were similar to the isolates from Korea. However, the group of Borrelia has different type of ospA in comparison with those of European B. valaisiana, indicating that the Borrelia species is divergent. Furthermore, some isolates from Sichuan and Anhui provinces were unique and 16S rRNA gene sequences of these Borrelia species showed similarity values ranging from 99.8 to 100% and clustered with each other on phylogenetic tree, but they were less than 99.0 with those of previously described Lyme disease Borrelia species. Therefore, we speculated that the B. valaisiana found in I. ricinus in Europe was adapted to the tick I. granulatus in central China, I. nipponensis in the southern tip of Korea, and I. columnae in Japan. Furthermore, unique Borrelia species are present in central China.