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University of Minnesota Extension

Tick diseases in horses

Quick facts

Ticks can transfer many disease-causing organisms to horses. Minnesota horse owners should be aware of two of the most common tick diseases:

  • Anaplasmosis

  • Lyme disease

Preventing tick disease

There are no vaccines available for anaplasmosis or Lyme disease, but there are prevention steps you can take.

  • Remove and destroy ticks as soon as possible.

  • Check horses for early signs of illness.

  • Reduce tick habitat near horses.

    • Clear brush out of pastures and along both sides of the fence line.

    • Keep pastures mowed.

  • Use a topical insecticide that includes a label claim for ticks.

    • Apply it to your horse before riding through long grass or brush.


Anaplasmosis is the most common tick-transferred disease to cause illness in horses. Humans and other animal species, including dogs and livestock can get a similar illness from ticks.

Deer ticks commonly transfer the bacteria from small mammals (deer mice and woodrats).


Lyme disease

Borrelia burgdorferi is the organism that causes Lyme disease and is a much less frequent source of illness in horses. Tick bites expose horses to this organism. Few horses develop clinical illness, usually months after the bite.


Julie Wilson, former University of Minnesota DVM

Reviewed in 2018

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