[Investigation on the vectors of Borrella burgdorferi and on the identification of the isolates along China-Russia border in Eastern Heilongjiang province, China].

Objective: To explore the fact that the east border of Heilongjiang had been a lyme disease natural focus,we investigated the species and distribution of ticks and isolated bacteria from ticks and identified genomic species of Borrelia burdorferi sensu lato. This study provided evidence for prevention and control of lyme disease.

Methods: Ticks were caught by flagging method and Direct immunofluorescence method was used to detect the rate of bacteria borne by the tick. BSK UI culture medium was used to isolate the agent and Specific McAbs were used to identify the bacteria. SDS-PAGE protein profile and PCR-RFLP method were also used to identify the species of Spirochetes.

Results: Ticks, collected from China-Russia border of east Heilongiiang province were classified including Ixodes persulcatus Schulze, Dermacentor sivarum Olener, Haemaphysalis concinna Kock,and Haemaphysalis japonica Kock. We found that the distributon of ticks was different under different circumstances and the predominant species were also different in different ports. The rate of bacteria borne by Iodes persulaatus Schulze was 31.4% ,by Dermacentor sivarum Olener and Haemaphysalis concinna Kock were 2.2% and 3.8%, respectively. However,it was negative for Haenaphysalis japonica Kock. Spirochetes isolated from Ixodes persulcatus Schulze were collected from Dongning and Tongjiang while Genomic species of Spirochetes, isolated from ticks of the border belonged to B. garinii.

Conclusion: All the results showed that the east border of Heilongjiang province was the natural focus of lyme disease.