Tick infestations in sheep in the UK

HARD ticks are distributed throughout the UK and there are concerns that their numbers are increasing and that their distribution and competency to transmit disease are changing, due partly to changes in climate and in land management. Ticks can transmit a variety of diseases, such as tickborne fever and louping ill, resulting in significant production losses and welfare problems in sheep flocks. The louping ill virus is also an important cause of high mortality in red grouse, which underpin the economy of many hill and upland areas of the UK. Control of louping ill virus in these birds often depends on control of the disease in sheep, which is becoming increasingly difficult and complex as a result of conflicts between sheep and grouse management and due to a decreasing number of acaricides available for tick control. Ticks can also transmit potentially serious diseases to humans and there is concern that the risks may be increased because of increased public access to tick‐infested countryside. This article describes the ticks affecting sheep in the UK and discusses the diseases they may cause. It also outlines the methods of tick control currently available.