Identification and characterization of 31 isolates of Borrelia burgdorferi (Spirochaetales, Spirochaetaceae) obtained from various hosts and vectors using PCR-RFLP and SDS-PAGE analysis

Abstract

Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis, circulates between ticks and vertebrate hosts. Two main genospecies typically occur in the Czech Republic Borrelia garinii and Borrelia afzelii, transmitted generally by Ixodes ricinus (L., 1758) ticks. The aim of our study was to identify spirochaete isolates focusing on Borrelia burgdorferi acquired from different sources: vectors (ticks), potential vectors (mosquitoes, small mites) and hosts (wild rodents). In the years 1996-2001 a total of 2398 ticks, 72 mites (from wild rodents), 2700 mosquito adults, 1798 mosquito larvae and organ parts (kidney and spleen) of 216 wild rodents were collected from seven localities in the Czech Republic. A total of 31 spirochaete strains were isolated: 13 strains from ticks, 1 strain from mite (Haemogamasus sp.), 15 strains from rodents, 1 strain from mosquito adults and 1 strain from mosquito larva. For the genospecies identification of these isolates PCR, PCR-RFLP was used and their characterization was also performed by SDS-PAGE. By nested PCR method all except one isolated strains were detected as Borrelia burgdorferi s.l. Following PCR-RFLP molecular analysis results, tick isolates were identified as B. garinii and B. afzelii, the strain isolated from the mite was identified as B. afzelii. This is the first isolated strain of B.b.s.l. from a different mite of infraorder Parasitiformes than tick. All of rodent isolates were identified as B. afzelii; mosquito adult isolate was identified as B. afzelii. Larval isolate from mosquito is spirochaete, but does not belong to Borrelia burgdorferi sensu lato group. © 2008 W. Stefański Institute of Parasitology, PAS.