Lyme Disease in Dogs

Lyme disease in dogs is a bacterial infection caused by Borrelia Burgdorferi bacteria. This bacteria is transmitted by ticks, especially deer ticks. Lyme disease is common in certain parts of the USA, particularly the Northeast, Midwest and the West.

Dogs that live in endemic areas are more likely to be infected. Besides dogs, human beings, horses and cattle can be develop Lyme disease.

How Lyme disease is transmitted to dogs

The bacteria is transmitted by 2 types of ticks: Ixodes and I. pacificus. The 3 stages of a tick are larva, nymph and adult. Larva and nymph feed on small mammals (such as mouse), while adult tick feeds on larger host (such as deer, dogs, humans, horses). Infected ticks attach to the host until they become engorged with its blood and then fall off.
It is during this time that a feeding tick transfers the bacteria from its mid-gut to the host. Transmission only occurs after at least 48 hours.

Lyme disease symptoms in dogs

About 95% of infected dogs do not show Lyme disease symptoms. It would take weeks or months after being infected before symptoms appear.

Some of the Lyme disease symptoms in dogs are:

– fever
– loss of appetite
– depression
– lameness in one limb or several limbs
– swollen joints
– pain on joints
– enlarged lymph nodes

Kidney failure, heart problem or nervous system disorder may occur in rare cases.

Other medical conditions may share these symptoms, so a proper diagnosis is necessary.

How to diagnose Lyme disease in dogs

It is difficult to diagnose Lyme disease in dogs. There is no one test for diagnosing the disease. While the standard test is for the presence of Lyme disease antibodies, it is not able to differentiate between exposure and infection to the disease. A dog exposed to the bacteria does not always develop and show symptoms of Lyme disease. Treatment is only required for an active infection.

The presence of symptoms, exposure to endemic area and the response to treatment may sometimes be enough to diagnose Lyme disease in dogs.

Treatment for Lyme disease in dogs

Lyme disease in dogs is treated with antibiotics. Symptoms should improve within 1-2 days of starting treatment.

Antibiotics only suppress but do not kill the Borrelia burgdoferi bacteria. The bacteria remain dormant in the dog’s body where it doesn’t cause active infection. Lyme disease can recur in dogs if the immune system is low.


  • Check your dog regularly for ticks by brushing with a flea comb. If ticks are removed immediately or within 48 hours of attaching to your dog, transmission does not occur.
  • Avoid tick infested areas such as wooded, bushy, leafy or grassy areas.
  • Keep your lawn mowed, and clear of leaves and overgrowth trees.

2 thoughts on “Lyme Disease in Dogs

  1. Amy

    Our lab is always in the woods. Is there a non chemical tick repellent to use? Have you heard of food grade diatomacious earth to powder on the dog/cat/human and it works on repelling/killing ticks.


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