Long-term persistence of Anaplasma phagocytophilumand Ehrlichia murisin wild rodents

Wild animals are reservoir hosts for a number of tick-transmitted agents, and long-term persistence of the agents is a key factor for their effective transmission from animal hosts to ticks. To study the persistence of Anaplasmataceae in rodents, 59 adult Myodesspp. voles (M. rutilus, M. rufocanus, and M. glareolus) were captured in Omsk Province, Asian Russia, freed from all ectoparasites, and kept in individual cages. Their blood samples were regularly analyzed for the presence of DNA of Anaplasma phagocytophilum, Ehrlichia muris, and “CandidatusNeoehrlichia mikurensis”. Anaplasma phagocytophilum, E. muris, and mixed infections were found in 29 (49 %), 17 (29 %), and 14 (24 %) voles, respectively. DNA of “CandidatusN. mikurensis” was not identified. Long-term persistence of A. phagocytophilumand E. murisin naturally infected Myodesspp. was shown for the first time. Thus, 12 animals with A. phagocytophilumwere found infected for more than three months and four of them carried the bacterium throughout 22–55 weeks of observation. Four voles were infected with E. murisfor 26–40 weeks. Fragments of groESLoperon were sequenced for genotyping A. phagocytophilumand E. muris. In voles with A. phagocytophilum, the determined sequences belonged to two phylogenetic clusters. Most sequences were identical or closely related to those found in small mammals and Ixodes triangulicepsticks from Western Siberia and European countries; one sequence was previously identified in rodents and Ixodes persulcatusand Ixodes pavlovskyiticks from Asian Russia. Sequences of groESLfragments from E. muriswere close to those determined previously in small mammals and I. persulcatusticks from Siberia. In addition, a new groESLsequence of E. muriswas identified in one vole and the sequence substantially differed from all known corresponding E. murissequences (≥ 14 mismatches).