Genetic polymorphism study and PCR detection of Borrelia burgdoferi [burgdorferi] sensu lato in Ixodes ricinus L. ticks in Lithuania

Abstract

The genetic variation and prevalence of Borrelia burgdorferi sensu lato infection in Ixodes ricinus ticks in Birzai and Vilnius districts in Lithuania, were investigated. 103 I. ricinus ticks (3 nymphs, 27 males and 73 females) were examined. DNA was extracted from individual ticks and analysed using polymerase chain reaction for taxonomic identification. In addition, the primers FL6 and FL7 were used to amplify the flagellin gene fragment of the spirochaete genome. Genetic polymorphism was investigated using the random amplified polymorphic DNA (RAPD) method. 10 arbitrary sequence decamers were used as primers. The similarities between RAPD patterns were used to evaluate the genetic distances among individual ticks. The genetic distances were used to construct a phylogenetic tree. The overall mean prevalence of B. burgdorferi sensu lato infection was 10.7% (11 ticks were infected), with 12.2% in Birzai and 9.3% in Vilnius. RAPD analysis revealed that 53 (98.15%) of the 54 loci examined were polymorphic, and the RAPD patterns showed a high degree of intraspecific variation. Phylogenetic analysis showed that some ticks in Birzai and Vilnius were similar and situated in the same clusters, however there were ticks that formed clusters according to sample site. Based on the dendrogram, the ticks from Birzai were most genetically distant. It is concluded that the Lithuanian I. ricinus population is heterogenic.