The ospC genes of twenty southern Borrelia burgdorferi sensu lato strains were amplified. The strains consisted of B. burgdorferi sensu stricto, B. andersonii , B. bissettii , and two undescribed genospecies, MI-8 and TXW-1. Nucleotide sequences of ospC and deduced amino acid sequences of these southern strains were aligned and phylogenetic trees were constructed based on analysis of the data. A similarity matrix based on amino acid sequences indicated that a high degree of similarity exists between B. burgdorferi sensu stricto and B. bissettii, and between B. bissettii and B. andersonii, and that the three genospecies are closely related. The highest degree of genetic diversity among them was observed in the two variable domains (V1 and V2), semivariable domain (SV), and the species-specific epitopes (between aa 28 and aa 31). Compared to European B. burgdorferi sensu stricto strains, American B. burgdorferisensu stricto strains show greater genetic heterogeneity. Great genetic diversity exists among southern B. burgdorferi strains. B. burgdorferi sensu stricto might be associated with different degrees of virulence and invasiveness. They also might be maintained naturally in particular tick and animal cycles in both the northern and southern U. S. Moreover, ospC genotypes might be associated with certain species of ticks and animal hosts. Ticks and host animals might be involved in the evolutionary process of the ospC gene.
Keywords: Borrelia burgdorferi, Lyme disease
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA