Ticks and tick-borne infections in sheep in the Nordic countries

Ixodes ricinus ticks are distributed throughout coastal areas in the Nordic countries, where they have an important role in the transmission of pathogens, in particular Anaplasma phagocytophilum and Louping-ill virus. The distribution of ticks appears to be changing, with spread to previously unaffected areas. Tick control is problematic and relies heavily on the application of systemic pyrethroid acaricides to their sheep hosts.