title: Co-infection with 'Candidatus Neoehrlichia Mikurensis' and Borrelia afzelii in Ixodes ricinus ticks in southern Sweden.
abstract: The tick-borne bacterium 'Candidatus Neoehrlichia mikurensis' has recently been recognized as a human pathogen in Europe and appears to be the second most common pathogenic bacterium in Ixodes ricinus ticks in central Europe, second to Borrelia afzelii. Here, we investigate the prevalence of 'Candidatus N. mikurensis' in host-seeking ticks in southern Sweden and the rate of co-infection with B. afzelii. We developed a real-time qPCR assay targeting the groEL gene of 'Candidatus N. mikurensis' and applied this assay to 949 I. ricinus ticks collected at several locations over 2 years. We found an overall prevalence of 6.0%, which means that Candidatus N. mikurensis is one of the most common tick-transmitted zoonotic agents in this area. Co-infections with both 'Candidatus N. mikurensis' and B. afzelii occurred in 2.1% of the ticks, which is significantly more than expected under random co-occurrence. The infection intensity (number of bacterial cells) of 'Candidatus N. mikurensis' was not affected by co-infection with B. afzelii, and vice versa. We conclude that there is a risk for simultaneous transmission of these 2 tick-borne pathogens. The potential medical consequences of this require further investigation.
authors.affiliation: Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Sweden. Martin.Andersson@biol.lu.se
authors.forename: Martin
authors.initials: M
authors.lastname: Andersson
authors.forename: Simona
authors.initials: S
authors.lastname: Bartkova
authors.forename: Olle
authors.initials: O
authors.lastname: Lindestad
authors.forename: Lars
authors.initials: L
authors.lastname: Råberg
mesh_terms: D000710:Anaplasmataceae / Q000235:genetics / Q000302:isolation & purification*; D000711:Anaplasmataceae Infections / Q000453:epidemiology / Q000382:microbiology*; D000818:Animals; D001096:Arachnid Vectors / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics; D015748:Borrelia burgdorferi Group / Q000235:genetics / Q000302:isolation & purification*; D018834:Chaperonin 60 / Q000235:genetics; D060085:Coinfection; D004269:DNA, Bacterial / Q000235:genetics; D006801:Humans; D018884:Ixodes / Q000382:microbiology*; D008193:Lyme Disease / Q000453:epidemiology / Q000382:microbiology*; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D013548:Sweden / Q000453:epidemiology; D015047:Zoonoses
chemical_list: D001426:Bacterial Proteins; D018834:Chaperonin 60; D004269:DNA, Bacterial