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Key takeaways

Lyme disease is an infectious disease spread by ticks and is caused by the bacteria Borrelia burgdorferi.

  • Lyme is of special concern because the pathogenic bacteria can also infect and cause lyme disease in people
  • Typical symptoms in dogs include lameness, fever, fatigue, swollen lymph nodes and joints and loss of appetite
  • In some cases, Lyme disease in dogs can develop into a more serious secondary kidney condition called Lyme nephritis
  • A blood test is able to determine dogs infected by Borrelia
  • Dogs with symptoms are usually treated with antibiotics and most make a full recovery in a short period of time
  • Tick control is a matter of public health so it is important for dogs to remain on a vet-recommended external parasite control regimen year round
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A closer look: Lyme Disease in Dogs

Ticks are one of the most common external parasites and are commonly found world wide and year round. These arachnids are vectors for many infectious agents, meaning they transmit diseases across different host species. One of the disease-causing bacteria that ticks carry is Borrelia burgdorferi, the pathogen responsible for Lyme disease.

Keeping pets on vet-recommended tick control all year significantly reduces the risk of all tick-borne illness, including Lyme disease.

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Risk factors

Ticks are found year round globally. All outdoor animals and animals who share living space with outdoor animals are at risk of exposure to ticks.

Current distribution maps define northeast, upper midwest, and West Coast states of the USA as areas where Lyme is endemic. Minnesota, Wisconsin, and all of the states north and east of North Carolina are particularly heavily infested. Cases of Lyme disease are rare outside of endemic areas.

A rare, serious complication of Lyme disease is Lyme nephritis or glomerular disease. The constant stimulation of the immune system by the Borrelia burgdorferi bacteria can lead to this type of kidney damage.

Many dogs, especially in tick-heavy areas, become infected with the bacteria associated with Lyme disease. Only approximately 5% of infected dogs develop symptoms of Lyme disease. Conversely, humans have a 90% likelihood of developing Lyme disease if they get infected.

Possible causes

Lyme disease is caused by transmission of Borrelia burgdorferi bacteria from a tick to a dog and by the proliferation of the bacteria to a sufficient level to cause symptoms.

Main symptoms

Testing and diagnosis

A blood test can tell the vet if the dog has been exposed to Borrelia burgdorferi. In endemic regions, this test is done as part of the annual checkup along with heartworm testing.

Steps to Recovery

Dogs diagnosed with Lyme disease usually undergo a 2 - 4 week course of antibiotics. Many dogs with Lyme disease improve within 48 hours of starting antibiotics. Non-steroidal anti-inflammatories and analgesics (painkillers) are indicated for dogs experiencing pain with Lyme disease.

The goal of treatment is to reduce the population of Borrelia burgdorferi to a level where they no longer cause symptoms. Some dogs experience a relapse of symptoms. Relapses may be triggered by reexposure to the pathogen from a new tick bite, so consistent use of a tick control product is recommended.

If nephritis is detected, the vet may prescribe antibiotics, a treatment to slow protein loss in urine, and immune suppression therapy. Dogs with Lyme nephritis can require aggressive therapy including IV fluid therapy and medications to reduce the effects of the kidney damage. Permanent kidney damage may result. Lyme nephritis can be life-threatening.


As with all tick-borne illness, Lyme disease is best prevented by keeping all pets in the household on year round vet-recommended external parasite control. Outdoor animals should be screened regularly for the presence of ticks. All ticks should be removed immediately.

Vaccination against Lyme disease is also recommended for dogs in endemic areas, but does not preclude the importance of taking preventative measures to avoid exposure to ticks.

Is Lyme Disease in Dogs common?

In endemic areas, 1.4 - 13% of dogs test positive for exposure to Borrelia. Infection is rare outside of endemic areas, but the geographic distribution of ticks is expanding. The development of full blown Lyme disease depends on the level of bacteria present in the dog’s system.

Typical Treatment

  • Antibiotics
  • NSAIDs
  • Painkillers


No Author - Writing for Centers for Disease Control and Prevention
No Author - Writing for Companion Animal Parasite Council
Wendy Brooks, DVM, DABVP - Writing for Veterinary Partner
No Author - Writing for American Veterinary Medical Association
No Author - Writing for Centers for Disease Control and Prevention

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