H 5 The rrf (5S)-rrl (23S) Intergenic Spacer Region Sequence Data Revealed the Presence of Borrelia bissettii from Ixodes pacificus and Ixodes angustus Ticks

M. G. MORSHED*^1,2, K. FERNANDO¹, S. K. BYRNE^1,2, R. CHEN¹, R. MANN¹, Q. WONG¹ and J. L. ISAAC-RENTON^1,2
1Laboratory Services, BC Centre for Disease Control and ² Department of Pathology and Laboratory Medicine, University of British Columbia,  Vancouver, B.C. 

Objective: The incidence of Lyme Disease is highest in the eastern parts of the United States. However, the Lyme Disease-causing spirochete, Borrelia burgdorferi, has also been cultured from Ixodes pacificus (Tick) and Peromyscus maniculatus (Deer Mouse) from the West Coast. The first B. burgdorferi strain was isolated in British Columbia (BC) in 1993 from an I. pacificus tick (Banerjee,1993). To date a total of 81 strains of B. burgdorferi, have been isolated or detected from the BC tick and mouse populations. All strains were initially identified as B. burgdorferi sensu stricto by morphology, motility, monoclonal antibodies and PCR using primers to amplify the OspA region.

Methods: In total between 1993 to 1999 we either isolated or detected 51 B. burgdorferi strains from ticks and 30 B. burgdorferi strains from mice. we amplified the rrf (5S)-rrl (23S) intergenic spacer region of 32 strains (22 isolated from I. pacificus, 6 isolated from I. angustus and 4 from deer mice) isolated from BC and the PCR products were sequenced.

Results: The sequence data showed that among 32 strains, 29 strains matched with B. burgdorferi sensu stricto whereas three strains matched with Borrelia bissettii isolated from the Ixodes angustus ticks and the remaining one was from I. pacificus.

Conclusion: Therefore, two genospecies of B. burgdorferi sensu lato are prevailing in British Columbia. This study also reports for the first time the presence B. bissettii in nature from an I. angustus tick.