Variability within the msp2 gene in populations of Anaplasma phagocythopilum.

Anaplasma phagocytophilum is an obligate intracellular bacterial parasite of verterbrate granulocytes. This bacterium is the aetiologic agent of human granulocytic anaplasmosis. The msp2 gene encoding major surface protein 2 is unique for Anaplasma and displays high antigenic variation. A fragment of the msp2 gene (334 bp) of A. phagocytophilum, amplified with DNA isolated from Ixodes ricinus, Syringophilidae, Capreolus capreolus and Canis lupus familiaris, was used to determine polymorphisms of Anaplasma within Polish populations. Sequence analysis of this fragment was used for observation of five different genetic variants of the bacterium within Polish sequences. The average genetic distance in Polish sequences was 0.7 % and the majority of observed substitutions had a synonymous character. High intraspecific variability observed in the msp2 gene of A. phagocytophilum is a strong proof of the high evolutionary plasticity, adaptation abilities, and abilities for fast distribution of this parasite in various environments.