Lyme Disease in Dogs

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Lyme disease, the most common tick-transmitted disease in the world, can affect dogs, most domesticated animals, and humans. The disease is caused by the Borrelia burgdorferi bacteria, which spreads through the bite of several species of ticks.

Lyme disease in dogs has been reported in every state in the United States, but it is more common in some geographical locations—specifically, the Northeast, upper Midwest, and northern Pacific coast. Dog owners who live or spend time in these areas should be aware of the symptoms of Lyme disease in dogs, as well as the preventative measures available.

Signs & Symptoms of Lyme Disease in Dogs

The symptoms of Lyme disease vary. While many dogs infected with Lyme disease may not exhibit any symptoms, others may show severe signs, including:

  • Lameness
  • Painful, swollen joints
  • Fever
  • Swollen lymph nodes
  • Loss of appetite
  • Lethargy
  • Kidney failure
  • Bruising or unexplained bleeding

Lameness, painful or swollen joints, fever, swollen lymph nodes, loss of appetite, and lethargy are the most common symptoms of Lyme disease in dogs and can range in severity. If left untreated, Lyme disease can lead to more serious symptoms, like damage to the kidney or the heart and nervous system.

Lyme disease commonly affects the kidneys more than the nervous system or heart. Unfortunately, it is often fatal. In cases of Lyme disease that affects the nervous system, seizure disorders and facial paralysis can occur.


Lyme disease symptoms can vary; common symptoms include fever and lameness. Cases of Lyme disease that affect the kidneys can be fatal.

How Did My Dog Get Lyme Disease?

Dogs contract Lyme disease through the bite of infected ticks. These ticks contain the bacteria Borrelia burgdorferi, which is a type of organism known as a spirochete.

Common Causes

There are at least four species of ticks in the world known to carry Lyme disease:

  • Ixodes pacificus
  • Ixodes scapularis
  • Ixodes ricinus
  • Ixodes persulcatus

In the United States, the most common source of transmission is the deer tick or black-legged tick, scientifically known as Ixodes pacificus on the West Coast and Ixodes scapularis on the East Coast. In Europe, the Ixodes ricinus and Ixodes persulcatus ticks carry Lyme disease.

These ticks are tiny, which can make them hard to see or feel on your dog, and all stages of the tick (larva, nymph, adult) can carry and spread the disease, although adult ticks tend to be the most infectious. It typically takes 24 to 48 hours after attaching to a host for the tick to spread the Lyme-causing bacteria, although transmission of disease can sometimes occur much more rapidly.

Certain areas are more prone to ticks than others. Wooded or grassy areas and areas with large tick populations pose the highest risk of infection. Ticks tend to be most active in the spring and fall when they are actively seeking hosts, which increases the risk of Lyme transmission. However, recent evidence indicates that ticks are also active in winter, as long as the temperature is above freezing.


Dogs contract Lyme disease from tick bites. Several species of tick can transmit the disease, but in the United States, deer ticks are the most common. These ticks usually need to be attached for at least 24 hours to transmit the bacteria that causes Lyme disease in dogs.

Diagnosing Lyme Disease in Dogs

Your veterinarian will diagnose Lyme disease based on your dog’s symptoms, history, and blood work. For example, a veterinarian may automatically suspect Lyme as the possible cause of lameness and fever in a dog from an area with high incidences of Lyme. To confirm the diagnosis, veterinarians will take blood samples to test for tick antibodies and rule out other potential causes of your dog’s symptoms. In some cases, your veterinarian may also recommend joint taps to assess the fluid in your dog’s joints.


Veterinarians diagnose Lyme disease through a combination of symptoms, physical examination findings, and diagnostics. Additional testing may be required to rule out other potential causes.

Treating Your Dog for Lyme Disease

Veterinarians treat dogs with Lyme disease through a combination of medical therapy and supportive care. A 4-to 6-week course of antibiotics will be prescribed for dogs with clinical signs of Lyme disease, as well as for dogs that have a high antibody level, even if they are asymptomatic. Many owners see improvement within a few days. However, a second round of antibiotics is often required, as the infection may persist through the first round of treatment. Severe cases of Lyme disease will acquire additional therapy to treat affected kidneys, heart, or nerves, along with supportive care like intravenous fluids. Re-checking blood work is recommended six months after completing antibiotic therapy to determine if treatment has been successful.

There is some debate within the veterinary community as to whether dogs should be treated if they test positive for Lyme disease but are asymptomatic and have a low antibody level. Your veterinarian will speak to you about different options so that you can come up with the best treatment plan for your dog.

Lyme disease can stay in your dog’s body even with antibiotics. In these cases, the disease often flares up when a dog’s immune system is suppressed or weakened, such as during periods of stress. The same antibiotic can be used to treat repeated recurrences of Lyme disease. Unlike other types of infections, the lingering infection is not a direct result of antibiotic resistance.

Additionally, dogs with painful symptoms like lameness may need medications like NSAIDs or steroids to help manage their pain. Restricting exercise is also important for these dogs, and owners can help by keeping their dogs calm and comfortable.

Is There a Cure for Lyme Disease?

There is a cure for Lyme disease. Antibiotics can resolve and in some cases eliminate the infection, and can also be used to treat recurrent infections. However, severe cases of Lyme disease that affect the kidneys, heart, and nervous system can be fatal.

Is Lyme Disease Contagious for Humans or Other Pets?

Lyme disease cannot be directly transmitted from an infected dog to humans and other pets. However, dogs can bring infected ticks into the household. These ticks can spread Lyme disease, along with other tick-borne diseases, to humans and other pets.

What Is the Cost for Treating Lyme Disease?

The cost of treating Lyme disease depends on the severity of the disease. If caught early, your veterinarian may prescribe antibiotics along with a follow-up appointment and regular blood work to monitor the condition. If the infection is severe at the time of diagnosis, on the other hand, your dog may require hospital care with supportive treatments (IV antibiotics, fluids, etc), which will be more expensive. Expect to pay for the initial office visit, diagnostic tests, medications, hospitalization, and any follow-up visits.


Lyme disease is a treatable condition. Antibiotics and supportive therapy will resolve the condition in many cases. While Lyme disease cannot be directly transmitted from dogs to other pets and humans, dogs can bring ticks indoors, where the ticks can attach to and infect both animal and human hosts.

Recovery and Management of Lyme Disease

You can expect to see improvement in mild cases of Lyme disease in dogs 3 to 5 days into antibiotic therapy. Severe cases may take longer and can be fatal if kidney damage is too advanced.

Antibiotics do not always eliminate Lyme disease. Dogs infected with Lyme disease will be prone to recurrence of the infection in the future, but antibiotics can be used again to treat the condition.

Owners can help manage their dog’s condition by complying with their veterinarian’s advice and following the instructions on the medication. Learning to recognize the signs of Lyme disease will also help owners get their dogs started on medication as soon as possible to prevent serious side effects in the future.


Antibiotics can manage Lyme disease in dogs. However, the disease can recur throughout the dog’s life. Understanding the signs and treatment options will ensure owners can get their dogs the treatment they need.

Preventing Lyme Disease

Lyme disease is preventable. The best way to avoid contracting Lyme disease is to avoid areas with high concentrations of ticks, like woods and grassy areas. Ticks are most active during the summer and fall, but infections are common during the summer as well as the winter in areas with mild winters. You should always manually check your dog (and yourself) for ticks after going for walks in tick-infested areas.

Administering a monthly tick preventative will also help prevent Lyme disease. Many of these preventatives kill ticks before they have had a chance to attach for 24 hours, reducing the risk of infection. If you live in an area with severe infestations of ticks, you may also want to consider treating your yard, although pesticide treatments carry risks of their own that should be discussed with your veterinarian.

Is There a Vaccine for Lyme Disease?

Yes. Your veterinarian may recommend the Lyme vaccine if your dog lives in a high-risk area or is in high-risk situations regularly. Like all vaccines, the Lyme vaccine is not 100 percent effective. Even with vaccination, your dog will still need monthly preventatives, and you should still take other preventative measures, like avoiding areas with ticks and manually checking your dog for ticks.


Lyme disease is preventable. The best way to prevent an infection is to reduce your dog’s exposure to ticks and stay up-to-date on monthly preventatives and Lyme vaccinations.

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