Tick-borne diseases in horses

With spring and summer, come ticks. They thrive in moist environments, tall grass, and undergrowth. Although horses are usually not particularly concerned about tick infestations, they can be infected by tick diseases.

Lyme disease and anaplasmosis are two diseases that ticks can carry, however, not all ticks carry bacteria. It can be difficult to establish if horse is suffering from one of these diseases.

How to prevent tick-borne diseases in horses

A tick bite on your horse doesn't automatically mean it is infected. It's still good to get into the habit of inspecting your horse every day so you can quickly find and remove any ticks. The longer a tick remains, the greater the risk of your horse becoming infected.

What is anaplasmosis in horses?

Anaplasmosis (formerly called ehrlichiosis) is a tick-borne disease, spread via tick bites. Common symptoms are high fever, swollen legs, unsteadiness, and reduced general condition and appetite. Sometimes yellowish mucous membranes can also be seen.

Not all infected horses show symptoms of illness.

Diagnosis of anaplasmosis

Preliminary diagnosis of anaplasmosis is based on clinical symptoms. The diagnosis is then confirmed by PCR analysis or by microscopy of blood smears. Through PCR analysis, the bacteria's DNA can be detected in the horse's blood.

Treatment of anaplasmosis

If your horse shows symptoms and the sampling shows a positive result, treatment is usually primarily with anti-inflammatory medication and rest. Antibiotics may also be needed if your horse exhibits serious and non-transitory symptoms.

Antibody control

Antibody control can be done to measure how many antibodies have been formed, which depends on how severe the infection was. The test result will show if your horse has been in contact with the bacteria at some point, but not when.

The fact that a horse has high levels of antibodies doesn't necessarily mean that it is affected by disease.

Approved by horse veterinarian Annette Graf, March 2024.

Other important guides on horse care:

Signs and symptoms of colic in horses - join in with Agria's #ColicCheck to help educate horses owners about common causes and symptoms of colic in horses

Acorn poisoning in horses - all you need to know about poisoning in horses in the autumn

Equine metabolic syndrome - what is it and how does it affect horses

About the Author

Amanda Andersson is a content writer Agria Djurförsäkring in Sweden, specialising in animal welfare. Previous experience includes Volvo on Demand, and 60plusbanken in Sweden.