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Ticks are able to inoculate infectious diseases into horses when feeding on them. Horses are especially prone to this, therefore, during the spring and autumn months. Owners should be aware of how to look for and how to remove ticks from their horses, thus reducing the risk of the horse becoming infected by a possibly fatal or devastating disease. There are a few tick diseases which owners could be confronted with and these include Equine Ehrlichiosis, Lyme disease, and Colorado Tick disease, and Equine Piroplasmosis.


Equine Ehrlichiosis

More specifically known as Equine Granulocytic Ehrlichiosis, this disease is caused by Anaplasma phagocytophilia. The disease is not contagious and both dogs and rodents may be affected by the causative agent. Equine Granulocytic Ehrlichiosis has mainly been found to occur in California although it has occurred elsewhere, including other states and parts of Europe.


Sheep and deer ticks can pass on the causative agent. There is no current vaccination for horses to prevent this disease. The disease can be treated, and this is done so by intravenously administering a drug called oxytetracycline. Despite this, it has been known for horses to recover by themselves, with no long term effects following recovery. Therefore, it is not likely that the disease leads to fatalities in a previously healthy horse.


The signs and symptoms of this disease include a raised temperature, swelling of the lower legs, a loss of appetite, a reluctance to move, and depression. Horses under the age of one may show little or no signs and symptoms whereas old older horses are more at risk of having more severe problems. It is not yet known if the disease is zoonotic. This means that there has been little evidence to suggest whether or not the disease is able to be transferred to humans from infected horses. It has been implied, however, that ticks may be able to pass the disease on to humans.


Lyme disease

Horses, humans and dogs can become affected by Lyme disease. Although they can become infected, horses tend to be less at risk to infection. Death does not generally occur in horses, although fatalities may result in affected foals. Also known as Borreliosis, Lyme disease is caused by Borrelia burgdorferi, which is passed on by sheep and deer ticks, mainly in woodland areas.


The causative pathogen can affect the brain or the nervous system. The signs and symptoms may include a slight rise in temperature, depression, a loss of appetite, lameness, oedema of the joints, and stiffness.  The horse may show changes in behaviour or eye pain.  Blood tests can be used to diagnose the disease. It must be noted that it is very difficult to diagnose previous to this as the disease can imitate the signs and symptoms of a great number of other diseases.


At the moment there is no vaccine for horses against this disease but there is a treatment available. An affected horse is usually treated orally with oxytetracycline There is no evidence as of yet to suggest that horses can transfer Lyme disease to humans. Horses do recover. Following recovery, however, there may be some long term problems.



Equine Piroplasmosis

Equine Piroplasmosis poses the most risk to horses between the months of August and October. This is not an overly common disease in the UK although it has occurred in other areas of Europe, such as France. The disease is caused by a protozoan known as the ‘babesia’ protozoan parasite. It can affect different animals depending on its type or strain including horses, cattle, dogs and humans. This disease does have the potential to cause fatalities in affected horses.


The signs and symptoms of the disease include a rise in temperature, depression, lack of appetite, and rapid shallow breathing. The horse may experience weakness, a lack of mobility, oedema of different body parts, anaemia, and jaundice. Owners may also notice that there is blood in the horse’s urine or the bladder ceases to function.


Treatments are available which include anti-protozoan drugs as well as supportive therapy. Following infection, this can be a very stressful time for both horse and owner. Horses have survived the disease although they may have long term problems following recovery, such as continued kidney problems or less energy during exercise.


Mountain Tick Fever

Also known as Colorado Tick Fever and the American Tick Fever, this is an acute viral infection which can seriously affects horses and is transferred by the wood tick. The affected parts of the horse’s body include the haemopoietic cells and the disease poses more risk to horses during the months between March and September.

The signs and symptoms of Mountain Tick Fever include a two staged fever, chills, light sensitivity and a rash. Humans can be affected by the disease and there is a high incidence of campers affected. It is not thought that horses can directly transfer the disease to humans.




Tick Prevention

In some areas of the world preventing a horse’s exposure to ticks is almost impossible. However, there are a few simple steps you could take to reduce the risk of your horse getting bitten. These include avoiding areas where there is a lot of long grass. Ticks tend to be found in areas of long grass and certain ticks, in woodland. Once a day, it would be advisable for owners to check their horse’s entire body if the area they are is known to be infested with ticks. If you do spot a tick then there is only one sure way to have it removed.  In areas of high tick infestations, it can be advised to use tick repellent sprays

Contrary to popular belief, you should not smother it with petroleum jelly as this can lead to the tick regurgitating the blood back into the horse, thus increasing the possibility of inoculating a disease. Special tweezers can be used to firmly remove the tick.  You can then dispose of the tick by immersing  it in a strong alcohol and then washing your hands.


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