Richter, Dania

ABSTRACT “ Candidatus Neoehrlichia mikurensis” ( Anaplasmataceae ) is an emerging pathogen transmitted by Ixodes ticks. Conventional PCR and the newly developed high-resolution melt PCR were used to detect and discriminate “ Candidatus Neoehrlichia mikurensis” and Anaplasma phagocytophilum . Both bacterial species were frequently found in Ixodes ricinus and Ixodes hexagonus but virtually absent from Dermacentor reticulatus . In rodents, “ Candidatus N. mikurensis” was significantly more prevalent than A. phagocytophilum , whereas in cats, only A. phagocytophilum was found.

ABSTRACT To estimate the likelihood of people coming into contact with the recently described tick-borne agent “ Candidatus Neoehrlichia mikurensis,” we compared its prevalence to those of Lyme disease spirochetes and Anaplasma phagocytophilum in questing adult Ixodes ricinus ticks collected in various Central European sites and examined ticks, which had been removed from people, for the presence of these pathogens. Whereas spirochetes infected questing adult ticks most frequently (22.3%), fewer than a third as many ticks were infected by “ Ca . Neoehrlichia mikurensis” (6.2%), and about a sixth harbored A. phagocytophilum (3.9%). On average, every twelfth encounter of a person with an I. ricinus tick (8.1%) may bear the risk of acquiring “ Ca . Neoehrlichia mikurensis.” Although a fifth of the people (20%) had removed at least one tick infected by “ Ca . Neoehrlichia mikurensis,” none displayed symptoms described for this pathogen, suggesting that its transmission may not be immediate and/or that immunocompetent individuals may not be affected. Because immunosuppressed patients may be at a particular risk of developing symptoms, it should be considered that “ Ca . Neoehrlichia mikurensis” appears to be the second most common pathogen in I. ricinus ticks. In our survey, only Borrelia afzelii appears to infect Central European vector ticks more frequently.