Candidatus Neoehrlichia mikurensis and its co-circulation with Anaplasma phagocytophilum in Ixodes ricinus ticks across ecologically different habitats of Central Europe

BACKGROUND: Candidatus Neoehrlichia mikurensis is a newly emerging tick-borne bacterium from the family Anaplasmataceae. Its presence in Ixodes ricinus ticks was reported from various European countries, however, it's ecology and co-circulation with another member of the same family, Anaplasma phagocytophilum has not been rigorously studied yet. FINDINGS: Candidatus N. mikurensis was detected in all sampling sites. In total, 4.5% of ticks were positive including larvae. The highest positivity was detected in Austria with a prevalence of 23.5%. The probability of Candidatus N. mikurensis occurrence increased with the proportion of ticks infected with Anaplasma phagocytophilum. CONCLUSION: A positive association between the occurrences of Candidatus N. mikurensis and A. phagocytophilum indicates that both bacteria share similar ecology for their natural foci in Central Europe.