Tick-borne diseases of cattle
Red Water Fever (Bovine Babesiosis) and Tick-borne Fever are two diseases which cattle can develop after being bitten by ticks.
Red Water Fever is caused by the protozoan parasite Babesia divergens. Cattle become infected when they are bitten by infected ticks, and the bacterium passes into the bloodstream. The disease is usually first reported in cattle in May or June when ticks start to become active. New cases may then continue to appear through to the autumn.
Clinically affected animals develop anaemia, and then fever and haemoglobinuria, i.e. blood in the urine – and hence the name Red Water Fever. Other signs include diarrhoea and an abnormally high heart rate with a loud audible heartbeat. Diagnosis is based on clinical signs, a history of exposure to ticks, and by microscopic examination of blood smears.
Factors which will predispose your cattle to clinical Red Water Fever are when: susceptible animals are introduced into an infected area; infected ticks are introduced by animals into a non-endemic area; and when infected cattle are introduced into areas with non-infected ticks.
Additionally, the immunity of cattle to the protozoan will lessen if there is a temporary decline in the tick population. When tick levels increase again, cattle may then succumb clinically to the disease. And any activities which cause stress to the animal – e.g. calving, transport - and reduce the animal’s immunity levels, may also result in clinical disease developing.
Calves of less than nine months of age are unlikely to succumb to the disease, as are cattle in endemic areas which have developed a good protective immunity due to exposure to the parasite.
Mild cases of Red Water Fever may recover without treatment. However, more severe cases will require treatment with a prescription-only medicine, administered by subcutaneous injection. The same product can also be used as a preventative strategy.
Tick Borne Fever
Tick-Borne Fever is another disease that is transmitted to cattle by ticks; it is caused by the bacterium Anaplasma phagocytophilum. Infection leads to fever, anorexia and weight loss, milk drop, and pain and swelling of joints. Young animals are at the greatest risk of infection because immunity is only developed through age and exposure, and none is acquired from colostrum. Effective treatment requires the use of an oxytetracyline antibiotic, administered within the first few days of infection.
The species of tick which is the vector for both diseases is the Ixodes ricinus; it is present throughout the UK. Uninfected ticks pose no risk. However in areas, where Red Water Fever and Tick-Borne Fever have been recorded, it is worth consulting with your vet as to whether preventative treatments are advised.