Neoehrlichia mikurensis: an emerging pathogen in Southeastern Poland – prevalence in Ixodes ricinus ticks and phylogenetic characterization

Zbigniew Zając, Joanna Kulisz, Renata Kunc-Kozioł, Aneta Woźniak, Angelique Foucault-Simonin, Pavle Banović, Alexandra Corduneanu, Sara Moutailler and Alejandro Cabezas-Cruz

A recent study led by Zbigniew Zając from the Medical University of Lublin uncovers the prevalence and genetic diversity of Neoehrlichia mikurensis in Ixodes ricinus ticks from southeastern Poland, highlighting its potential as an emerging public health threat. Published in the Annals of Agricultural and Environmental Medicine, the study focuses on this Gram-negative bacterium, which can cause febrile illnesses often misdiagnosed due to non-specific symptoms.

Ticks were collected during June and July 2022 from meadow and forest habitats in the Subcarpathian Region. Out of 412 ticks, 6.35% of females and 2.38% of males tested positive for N. mikurensis. No infections were detected in nymphs, and prevalence did not significantly differ between habitats. However, a forest site showed a higher infection rate among female ticks.

Genetic analysis of the groEL gene revealed low diversity, with two main haplotypes (H1 and H2) identified. The dominant haplotype, H1, is consistent with strains found across Europe and Asia, indicating a cosmopolitan distribution and limited evolutionary divergence within Europe.

These findings confirm I. ricinus as a critical vector for N. mikurensis in Europe. Although the pathogen’s prevalence in this study is modest, its ability to cause persistent febrile illnesses emphasizes the need for increased public awareness and monitoring in regions with high tick activity.

This study contributes essential data for the surveillance of tick-borne pathogens and underscores the importance of preventive measures in endemic regions to mitigate the risks of N. mikurensis transmission to humans.