Tick Borne fever, as the name suggests, is transmitted by ticks between sheep and can cause a varying degree of clinical signs and consequences on farm. It is caused by a ricketsial bacteria Anaplasma phagocytophilum.
Typically one of the most common effects first noticed is abortion in ewes, but it can also cause immunosuppression leading to variable presentations on farm. Clinical signs can just be a transient increase in temperature in non-pregnant ewes, with a reduced appetite and depression. Other common presentations can include an exacerbation of respiratory issues on farm, an increase in joint ill cases in lambs and overall reduced immunity. Co-infections with other tick borne diseases such as Tick Pyaemia and Louping Ill can also occur.
Abortion typically occurs when naive pregnant ewes, that have not previously been exposed to Tick Borne Fever, are infected. This can lead to very high abortion rates. Diagnosis of Tick Borne Fever is by blood sample, either to identify the parasites visually on a blood smear or through antibody response to the disease.
Control of Tick Borne Fever is best achieved through use of topical insecticides to minimise exposure to ticks on farm. Anaplasma phagocytophilum will also respond to oxytetracycline but it is important to have a confirmed diagnosis prior to treatment particularly in cases of an abortion outbreak. Tick borne diseases will become increasingly important with the warmer weather over the coming years.
Speak to one of our RAMAs or feel free to discuss with one of team sheep about how to minimise risk on farm.
Written By Ellen Taylor, Veterinary Surgeon