The Occurrence of Zoonotic Anaplasma phagocytophilum Strains, in the Spleen and Liver of Wild Boars from North-West and Central Parts of Poland

PURPOSE: The Anaplasma genus includes a Gram-negative bacterium infecting the blood cells of wild and domestic mammals, causing tick-borne fever. Infection with pathogenic Anaplasma phagocytophilum strains may cause Human Granulocytic Anaplasmosis. Wild boars (Sus scrofa) may act as natural wild reservoir hosts for potentially zoonotic A. phagocytophilum strains; however, there is still little data to confirm this statement. The aim of this study was to verify whether wild boars can be classified as natural reservoirs of Anaplasma spp. and to compare the suitability of spleen and liver samples for such analysis. METHODS: Liver and spleen samples were collected from 59 wild boars (2017–2019). The organs were tested for Anaplasma phagocytophilum using short (partial) fragments of three markers: 16S rRNA, groEL, ankA. RESULTS: Anaplasma spp. DNA was detected in 12 out of 59 samples, with a prevalence of 20.34%. The presence of A. phagocytophilum was confirmed by sequencing of the partial 16S rRNA gene. Positive individuals were tested for the characteristic markers: groEL and ankA. The analysis of the nucleotide sequences of 16S rRNA, groEL and ankA, indicated that the strains of A. phagocytophilum detected in these studies are potentially zoonotic for humans. CONCLUSION: Wild boars from Poland can be classified as a natural reservoir of the zoonotic strain of Anaplasma phagocytophilum. Both the spleen and the liver tissues were found to be suitable materials for the detection of A. phagocytophilum.