Find in Library

<i>Ixodes ricinus</i> nymphs and adults removed from humans, and larvae and nymphs from birds, have been analysed for infection with <i>Babesia</i> species and <i>Borrelia</i> species previously in separately published studies. Here, we use the same data set to explore the coinfection pattern of <i>Babesia</i> and <i>Borrelia</i> species in the ticks. We also provide an overview of the ecology and potential public health importance in Sweden of <i>I. ricinus</i> infected both with zoonotic <i>Babesia</i> and <i>Borrelia</i> species. Among 1952 nymphs and adult ticks removed from humans, 3.1% were PCR-positive for <i>Babesia</i> spp. Of these <i>Babesia</i>-positive ticks, 43% were simultaneously <i>Borrelia</i>-positive. Among 1046 immatures of <i>I. ricinus</i> removed from birds, 2.5% were <i>Babesia</i>-positive, of which 38% were coinfected with <i>Borrelia</i> species. This study shows that in <i>I. ricinus</i> infesting humans or birds in Sweden, potentially zoonotic <i>Babesia</i> protozoa sometimes co-occur with human-pathogenic <i>Borrelia</i> spp. Diagnostic tests for <i>Babesia</i> spp. infection are rarely performed in Europe, and the medical significance of this pathogen in Europe could be underestimated.