Anaplasma phagocytophilum in temperate and cold regions of Europe: a review on its prevalence in livestock

In Europe, Anaplasma phagocytophilum infections in livestock have been reported in several countries, particularly in northern and central Europe, where the climate is temperate or cold. In these regions, the infection is most commonly observed in grazing animals, such as cattle and sheep, during the summer months. The prevalence of A. phagocytophilum infection in livestock can also vary within countries depending on the farming practices and management of the animals. Different studies report varying rates of infection in different countries and regions. In Europe, seroprevalence in livestock has been reported to range from 0% to 55%, with higher rates observed in regions with high tick densities. Molecular methods detect 0% to 85.71% (in animals with clinical symptoms) and 23.94% (using random selection) of A. phagocytophilum genetic material in farm animals. As the infections of Anaplasma spp. bacterium are often asymptomatic or clinical symptoms are not specific in some cases, we hypothesise that there are more anaplasmosis cases in Europe than expected. In this review we analysed scientific data excluding clinical cases, even though there are multiple cases described in different countries in the region of our review.