Investigation of vector and host infection of lyme disease in Jinghong, Yunnan

ObjectiveTo understand the infection status and pathogenic characteristics of lyme disease in rats and ticks in Jinghong county of Yunnan province.

MethodsIn March 2018, the specimens of ticks were collected from 7 villages in Jingne and Dadugang townships of Jinghong, and divided into two groups. The specimen in one group were used to culture Borrelia burgdorferi with BSK-Ⅱ medium and the specimen in another group were used to extract DNA for detection of carrier rate. The kidney and bladder specimens of rats were collected from 4 villages in Menghan, Mengyang, Gasa and Jingne townships to culture pathogens and extract DNA. The DNA samples were detected by real-time PCR for the recA gene. The positive samples of recA gene were detected by nested PCR for 5S–23S rRNA gene spacer, and the amplified products were sequenced and compared with sequence homology.

ResultsA total of 724 Boophius microplus and 35 Rattus flavipectus were captured, but no B. burgdorferi strains were isolated from 524 ticks and 35 rats. Three of 200 ticks were positive for recA gene, while 35 rats were negative. The 5S–23S rRNA sequence homology analysis of the three positive specimens showed that they belonged to B. garinii.

ConclusionThere was infection of B. garinii in ticks in Jinghong, and Boophius microplus might be the vector. Therefore, the surveillance in local population, host and vector should be strengthened.