April Showers bring … puddles and ticks (Part 2): Lyme disease

By Dr. Emma Bush

A few weeks ago we shared about one of the five main vaccines that we use for our canine pets in the Maritime Provinces: the Leptospirosis vaccine. Today we will be talking about another common vaccine for dogs that protects against a different type of bacterial infection: Lyme Disease.

What is it?

Lyme disease is the name for the clinical illness caused by infection with the Borrelia burgdorferi bacteria. This bacterium is spread through tick bites, specifically from the black legged tick or deer tick. These ticks become infected by feeding on wildlife, they then pass that bacteria on to the next animal that they bite and feed on (such as our dogs, or even ourselves). Ticks must be attached for 48 hours in order to allow transmission of the bacteria. As such, if the tick falls off and dies or is removed prior to this time passing, the bacteria is not transmitted and infection is not possible.

It is important to note that Lyme disease looks very different in our canine pets than it does in people. In humans, we will see the characteristic bullseye rash and development of symptoms in 90% of cases. However, thankfully, only 5% of canine patients that are infected develop clinical disease / symptoms. In addition, if they are to develop symptoms, this illness generally does not begin for weeks or even months following transmission and infection.

Clinical signs in dogs are most commonly shifting-leg lameness. However, general signs of illness including fever can also be noted. In rare, severe cases, dogs can develop severe kidney disease secondary to infection with Lyme, called Lyme Nephritis. In even rarer cases, cardiac (heart) and neurologic signs can occur. However, it is worth repeating that most infected dogs do not develop clinical signs of illness with Lyme disease.

Testing and Treatment

Because not every dog that gets infected with Lyme disease presents with clinical disease, not every dog that gets Lyme disease requires treatment. Dogs with symptoms of Lyme disease (such as shifting-leg lameness) should be tested to rule Lyme disease in or out – this is important as there are a variety of causes of lameness in dogs. The most common test for Lyme disease assesses antibody load (evidence of the body fighting off infection) and so is not accurate until 5-7 weeks after tick bite/transmission as it takes time for the body to mount a response to infection.

For any dog that tests positive for Lyme disease it is recommended to do further bloodwork and urine testing to ensure appropriate kidney function given the rare occurrence of kidney disease with Lyme disease.

If there is evidence of kidney disease, this is very serious. These dogs require medications for both Lyme disease and for kidney disease. They sometimes even require immunosuppressive medications. These dogs are very ill, require hospitalization and supportive care and can have severe lasting damage.

Fortunately, more commonly dogs present with arthritic changes / shifting leg lameness as above. This is treated simply with an extended course of antibiotics (either oral or injectable). These patients generally improve within a few days. Ultimately, obvious signs of Lyme Disease should resolve completely with antibiotic therapy. However, it is currently unknown if the bacterial infection is completely resolved with treatment.


The mainstay of prevention of Lyme disease is through tick prevention products. These come in multiple different varieties; including oral and topical. This is the number one method for prevention of transmission and infection.

As mentioned above, there is also a vaccine for Lyme disease in dogs. This is considered a third-tier of prevention, with the first two tiers being regular use of tick prevention products; and removing ticks when found. However, the vaccine is absolutely recommended as an additional tier of protection, particularly in dogs in highly tick infested areas that are at high risk for Lyme disease.

If you have any questions or concerns about Lyme Disease in your canine pet, parasite prevention, or vaccination, please contact your veterinarian.

References Used:

Lyme Disease in Dogs: https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4952009 Testing for Lyme Disease in Dogs: https://vcacanada.com/know-your-pet/testing-for-lyme-disease-in-dogs