First report of Anaplasma marginale in the European bison Bison bonasus

European bison, Bison bonasus, is a strictly protected species of large mammal, with 25% of the world's population living in Poland. The most numerous populations of European bison live in the Białowieża Primeval Forest, northeastern Poland, and in the Bieszczady Mountains, southeastern Poland. The purpose of this study was to investigate the occurrence of Anaplasma spp. in B. bonasus from Poland.

Tissue samples were collected from 45 European bisons between 2021 and 2024 in the Białowieża and Bieszczady areas. Two genetic markers, 16S ribosomal DNA (rDNA) and msp4, were used for the detection, genotyping, and phylogenetic analysis of bacteria from the genus Anaplasma.

The prevalence of Anaplasma spp. was 40% (18/45) in the examined samples. Anaplasma phagocytophilum was detected in 10 samples, and eight samples were found to be positive for the presence of Anaplasma marginale DNA.

This study is the first report of A. marginale occurrence in Poland and the first report of A. marginale occurrence in B. bonasus in Europe. Infection by the pathogenic A. marginale in strictly protected species such as the European bison may have an impact on the health, ecology, and conservation of this endangered species.