Lyme Disease in Dogs

What Is Lyme Disease in Dogs?

Lyme disease, also called borreliosis, is a bacterial infection in dogs that is spread by tick bites. Although Lyme disease can also affect people, dogs don’t spread the infection to their pet parents. Lyme disease in dogs can cause serious complications, such as joint inflammation (swelling) and kidney failure.

When a tick bites a dog, the bacteria that causes Lyme disease (Borrelia burgdorferi) passes from the tick’s saliva to the dog’s bloodstream, where they can infect the joints, heart, brain, and spinal cord.

Some infected dogs may show no obvious symptoms, while others may become very sick. This largely depends on how strong the dog’s immune system is and how long the infection is present before treatment begins.

Dogs who do outdoor activities—such as hiking or hunting in wooded areas—are at greater risk for Lyme disease because of their increased exposure to ticks.

Dogs and puppies who are unvaccinated and those who are not kept up to date on tick preventatives are also most vulnerable to infection. It’s estimated that between 1.4% and 13.3% of dogs in the United States test positive for Lyme disease.

Although Lyme disease can be found in most states, it is most common in the Midwest, Northeast, Southeast, and West. Cases are most likely to be diagnosed during spring, summer, and fall, when the weather is warmer and ticks are more prevalent.

Dogs with Lyme disease generally live normal lifespans if treatment is started early.

If left untreated, Lyme disease in dogs can cause kidney failure, which is life-threatening. For this reason, dogs having symptoms of Lyme disease should be treated as medical emergencies. If you suspect your dog has Lyme disease, take them to the veterinarian immediately.

Symptoms of Lyme Disease in Dogs

Symptoms of Lyme disease in dogs may not occur if a dog’s immune system is able to control the infection. If a pup does develop symptoms, pet parents may notice the following:

• Joint pain or swelling

• Lameness

• High fever

• Lethargy

• Weakness

• Decreased appetite

• Enlarged lymph nodes

• Vomiting

• Diarrhea

• Increased thirst

• Increased urination

• Weight loss

• Swollen legs or belly

Causes of Lyme Disease in Dogs

Lyme disease in dogs is caused by an infected tick, specifically from the Ixodes genus.

I. scapularis (deer tick) and I. pacificus (western blacklegged tick) are the two main ticks that spread Borrelia burgdorferi.

Ticks become infected with B. burgdorferi by feeding on rodents and birds. The bacteria multiply within the tick and are spread to a dog when the tick bites it.

To pass on the infection, the tick must be attached to the dog for at least 24 to 48 hours.

How Veterinarians Diagnose Lyme Disease in Dogs

To diagnose Lyme disease in dogs, veterinarians will use a combination of tests and a discussion with the pet parent. Your vet will want to know about any recent travel history, any recent exposure to ticks, and any symptoms the dog has.

Diagnostic tests that may be done to identify Lyme disease in dogs include:

• SNAP 4Dx—A few drops of blood are taken from a dog’s vein, mixed with a special solution, and then used to test for antibodies. Results are available in just eight minutes, and vaccination against Lyme disease does not affect the results.

• Polymerase chain reaction (PCR)—This test uses blood, joint fluid, or a lymph node sample to test for Lyme disease.

• Blood work—Blood can be collected from a dog’s vein to check overall health and rule out other underlying conditions that may look like Lyme disease.

• Urinalysis—A sample of urine is taken to check for signs of protein, which can be a sign of kidney disease in dogs who have tested positive for Lyme disease.

Treatment of Lyme Disease in Dogs

Lyme disease in dogs is most often treated using an antibiotic called doxycycline. It’s given to a pup for at least 30 days. Dogs are expected to show improvement in their symptoms in as little as 24 hours. Other antibiotics—amoxicillin and cefovecin—can be used if dogs are sensitive to doxycycline.

Pain medications, such as gabapentin, may be given if there is joint swelling or discomfort. Steroids and other immunosuppressant medications may be used in some cases if considered helpful by the veterinarian. 

Dogs with severe disease may need hospitalization for supportive care, including intravenous (IV) fluids and medications to support the kidneys.

Recovery and Management of Lyme Disease in Dogs

After starting antibiotic treatment, most dogs start feeling better within one to two days. Lyme disease in dogs must be treated for at least 30 days to get rid of the bacterial infection. With early diagnosis and treatment, most cases of Lyme disease in dogs are curable.

However, some dogs may have lasting lameness if the dog was chronically infected or treatment was delayed. These dogs may need a longer course of antibiotics as well as other medications—such as pain management—for the rest of their lives. Providing an orthopedic dog bed can help these dogs feel more comfortable. Portable stairs can also help dogs get on and off sofas and chairs, preventing jumps on and off and further joint irritation.

If the infection has reached the kidneys, it’s very difficult to cure Lyme disease, and dogs typically need long-term medical management. These dogs have a poor prognosis. If a dog’s quality of life has significantly decreased, the veterinarian may recommend humane euthanasia to relieve suffering.

Prevention of Lyme Disease in Dogs

There are two main ways to prevent Lyme disease in dogs—vaccination and tick preventatives.

The Lyme vaccine is given to puppies at 12 weeks of age, followed by a booster three weeks later. It’s then given yearly while a dog is considered at risk. Dogs who live in or travel to areas of the country where Lyme disease is prevalent should get the vaccine.

Topical or oral products that prevent and kill ticks are important in protecting dogs against tick bites and Lyme disease. Products that may be recommended by your veterinarian include Bravecto®, NexGard®, and Simparica Trio™. Dogs should be kept on tick preventatives year-round for the best protection.

Other important preventative measures pet parents can take include checking dogs for ticks, immediately removing any you find from your dog, and keeping dogs out of heavily wooded areas where tick populations are high.