Lyme Disease Symptom in Dogs

Posted by Lianne McLeod D.V.M. on

Lyme Disease Symptom in Dogs

Lyme disease, a prevalent illness transmitted by ticks, threatens humans and our cherished canine companions.   In this comprehensive piece, we will explore the intricacies of Lyme disease in dogs, covering its origins, causes, symptoms, diagnosis, and treatment. 

Moreover, we will touch upon additional ailments that can be transmitted to dogs by these tiny parasites.  We aim to empower you with the understanding necessary to safeguard your beloved furry pals from this affliction and guarantee their optimal health.

Ticks and Their Habitats

Ticks are small arachnids that are primarily known for their parasitic feeding habits.  These creatures are found in various habitats worldwide, but those carrying Lyme disease have specific areas they prefer.  They are commonly found in tall grasses, thick brush, marshes, and woods. These environments provide them with the necessary cover and access to hosts for feeding.

Lyme disease was named after the town of Lyme, Connecticut, where many cases were reported in 1975.  Since then, awareness and recognition of the disease have grown, and cases have been reported in every US state. However, it’s more common in certain regions. 

areas where ticks prominently carry lymes disease - Northeast, Upper Midwest, Pacific Coast

The Northeast, upper Midwest, and northern Pacific coast have a higher prevalence of Lyme disease.  This distribution pattern is largely due to the specific habitats favored by the ticks that carry the bacteria causing Lyme disease.

Understanding these habitats is crucial for prevention. If you live in or near these areas or if your dog spends a lot of time in these environments, it’s important to take preventative measures to protect your dog from tick bites and Lyme disease.

Causes and Transmission

Lyme disease in dogs is primarily caused by the bacterium Borrelia burgdorferi, which is transmitted through the bite of infected ticks. 

At least four types of ticks can transmit the bacteria:

  • In the Northeast and upper Midwest - the Black-Legged Tick (Ixodes scapularis)
  • On the Pacific coast - the Western Black-Legged Tick (Ixodes pacificus)
  • In the East, Southeast, and Midwest - The Lone Star Tick (Amblyomma americanum)
  • Throughout the eastern United States - The American Dog Tick (Dermacentor variabilis)

Ticks become infected with Borrelia burgdorferi as juveniles, typically during their first blood meal.  This infection usually occurs when they feed on an infected wildlife host, such as a mouse or bird. 

tick transmission diagram

Once infected, the tick can transmit the bacteria to subsequent hosts during feeding.  It’s important to note that not all ticks are infected with Borrelia burgdorferi. 

Over 70% of adult black-legged ticks in endemic regions carry the bacteria.  However, this percentage can vary greatly depending on the location and time of year.

Lyme Disease Buildup

When an infected tick bites a dog, it takes at least 24-48 hours for the bacteria to be transmitted.  During this time, the bacteria leave the tick’s gut and enter its salivary glands. 

From there, they are injected into the dog’s bloodstream during feeding.  Once in the bloodstream, Borrelia burgdorferi can cause a local infection at the bite site. Over time, they can spread and cause a more systemic infection, affecting various tissues and organs.

Symptoms of Lyme Disease in Dogs

Lyme disease can present a range of symptoms in dogs, but it’s important to note that many infected dogs may not show symptoms at all

Only 5 to 10% of infected animals show symptoms, which may appear 2 to 5 months post-infection.  This duration can make Lyme disease difficult to diagnose and treat in its early stages. 

However, being aware of the common symptoms can help you identify potential cases of Lyme disease in your dog.

Common Symptoms

The most common symptoms of Lyme disease in dogs include:

dog showing symptoms of lyme disease
  1. Lameness:  This symptom is often the first sign of infection.  It can be intermittent, mild, or severe, affecting one or more joints.  It usually lasts 3 to 4 days but may recur days to weeks later in the same or different legs.
  2. Painful-swollen joints:  Dogs with Lyme disease often experience joint pain and inflammation. This symptom can result in a stiff gait, difficulty moving, or reluctance to play or exercise.
  3. Fever:  A high temperature is another common symptom.  However, it can be difficult to detect without a thermometer, as dogs do not show signs of fever as humans do.
  4. Swollen lymph nodes:  The lymph nodes near the site of the tick bite may become swollen and tender.
  5. Loss of appetite:  Dogs with Lyme disease may lose their appetite due to feeling unwell.
  6. Lethargy:  Infected dogs often seem tired and may sleep more than usual.
  7. Kidney damage:  In rare cases, Lyme disease can cause kidney damage, which can be serious and potentially life-threatening.  Symptoms of kidney damage include vomiting, diarrhea, weight loss, increased urination and thirst, and fluid build-up in the abdomen or under the skin.

Other Symptoms

In addition to the common symptoms listed above, some dogs with Lyme disease may also experience other symptoms, such as heart abnormalities, nervous system complications, and shifting-leg lameness.

If your dog is showing any of these symptoms, especially if they have been in an area where ticks are common, it is important to consult with a veterinarian as soon as possible.  Early detection and treatment can help prevent more serious complications of Lyme disease.

Diagnosis of Lyme Disease in Dogs

Diagnosing Lyme disease in dogs can be complex as the symptoms can be similar to other conditions, and many infected dogs do not show symptoms.  However, a combination of symptoms, history, and blood work can help veterinarians make a diagnosis.

diagnosis of lyme disease

Symptoms and History

The first step in diagnosing Lyme disease is a thorough examination of the dog and a detailed history from the owner.  The veterinarian will look for common Lyme disease symptoms such as lameness, swollen joints, fever, loss of appetite, and lethargy.  They will also ask about the dog’s history, including any known tick bites, time spent in tick-infested areas, and previous health issues.

Blood Work

blood work

If Lyme disease is suspected based on the symptoms and history, the next step is usually blood work.  Blood samples are taken to test for antibodies to the bacteria that cause Lyme disease.  The dog’s immune system produces these antibodies in response to infection.

Serologic Assays

Serologic assays are the most common diagnostic method for Lyme disease in dogs.  These tests detect antibodies to Borrelia burgdorferi in the dog’s blood.  Several serologic assays exist, including enzyme-linked immunosorbent assay (ELISA) and Western blot.  These tests can provide strong evidence of infection, but they cannot distinguish between current and past infections.

Joint Taps

In some cases, joint taps may be recommended to assess joint fluid, especially when joint pain or swelling is present.  This procedure involves taking a fluid sample from the affected joint(s) for analysis.  The presence of inflammatory cells or bacteria in the joint fluid can support a Lyme disease diagnosis.

It’s important to note that while these tests can help diagnose Lyme disease, they are not 100% accurate, and false positives or negatives can occur.  Therefore, the diagnosis of Lyme disease in dogs is typically based on a combination of symptoms, history, and diagnostic test results.

Treatment for Lyme Disease in Dogs

The treatment for Lyme disease in dogs primarily involves antibiotics, with the most commonly prescribed being doxycycline and minocycline.  These antibiotics are typically given for a 4 to 6-week course, although the exact duration may vary depending on the severity of the disease and the dog’s response to treatment.

Antibiotic Treatment

Doxycycline and minocycline are part of the tetracycline class of antibiotics, which work by inhibiting bacterial protein synthesis.  These antibiotics effectively stop the bacteria from growing and reproducing, allowing the dog’s immune system to eliminate the infection.


It’s important to note that while antibiotics can effectively treat Lyme disease, they may not always eliminate the disease.  In some cases, bacteria can remain in the dog’s body in a dormant state, potentially leading to a recurrence of symptoms later.  Therefore, monitoring your dog closely for any signs of illness is crucial, even after treatment has been completed.

Severe Cases Treatment

In severe cases of Lyme disease, additional therapy and supportive care may be required.  This treatment can include intravenous fluids to treat dehydration, pain medication to manage joint pain and inflammation, and dietary changes to support kidney function if kidney damage has occurred.

Pain Management

Dogs with painful symptoms may need non-steroidal anti-inflammatory drugs (NSAIDs) or steroids to help manage their pain.  These medications can reduce inflammation and provide relief from joint pain and swelling.  However, they should be used under the supervision of a veterinarian as they can have side effects, especially long-term use.

Follow-Up Care

After treatment, regular follow-up visits with your veterinarian are important to monitor your dog’s recovery and check for any signs of recurrence.  Your vet may also recommend regular blood tests to monitor your dog’s antibody levels against Borrelia burgdorferi.

Tick Removal and Prevention

Preventing Lyme disease in dogs primarily involves protecting them from tick bites. This prevention can be achieved through tick removal, avoiding tick-infested areas, and using tick preventatives.

Tick Removal

If you find a tick on your dog, it’s important to remove it as soon as possible to reduce the risk of disease transmission.  Ticks should be removed carefully using a tick remover or a pair of fine-tipped tweezers.  The goal is to remove the entire tick, including its head, which can become embedded in the skin.

tick removal

Steps to remove a tick include:

  1. Grasp the tick as close to the skin’s surface as possible using fine-tipped tweezers.
  2. Pull upward with steady, even pressure.  Don’t twist or jerk the tick, as this can cause the mouth-parts to break off and remain in the skin.
  3. After removing the tick, thoroughly clean the bite area and your hands with rubbing alcohol, soap, and water.

Removing a tick within 24 hours can prevent infection, as it usually takes at least 24-48 hours for the bacteria causing Lyme disease to be transmitted from the tick to the host.

Avoiding Tick-Infested Areas

The best prevention is avoiding areas where ticks are common.  These include tall grasses, thick brush, marshes, woods, and areas with high deer populations.  If you live where ticks are common, keep your dog out of these environments, especially during peak tick season.

Tick Preventatives

Monthly tick preventatives and year-round use of tick-preventive products, such as Bravecto and Nexgard, are recommended for dogs at risk of exposure to ticks. 

These products can include oral medications, spot-on treatments, sprays, and collars.  They work by killing or repelling ticks that come into contact with your dog, preventing them from biting and transmitting diseases.


Vaccination against Lyme disease is available for dogs and can be an additional tool in preventing this disease. 

lyme vaccination

However, it’s important to note that vaccination may not always be 100% effective and should not replace other preventative measures such as regular tick checks and the use of tick preventatives.

Other Canine Diseases Carried by Ticks

Ticks are not only carriers of Lyme disease, but they can also transmit various other diseases to dogs. These diseases can cause a range of symptoms and health problems, some of which can be serious or even life-threatening. Here are some of the other diseases that ticks can transmit to dogs:


Ehrlichiosis is caused by the bacteria Ehrlichia, which is transmitted to dogs through the bite of an infected tick.  Symptoms can include fever, loss of appetite, weight loss, nose bleeds, and swollen limbs.


Anaplasmosis is caused by the bacteria Anaplasma platys and is transmitted to dogs through the bite of an infected tick.  Symptoms can include fever, loss of appetite, lethargy, lameness, and joint pain.

Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever is caused by the Rickettsia rickettsii bacteria transmitted to dogs through the bite of an infected tick.  Symptoms include fever, vomiting, diarrhea, coughing, and abdominal pain.


Babesiosis is caused by protozoan parasites of the genus Babesia, which are transmitted to dogs through the bite of an infected tick. Symptoms include fever, anemia, jaundice, dark urine, and enlarged spleen.


Bartonellosis is caused by bacteria of the genus Bartonella and is transmitted to dogs through the bite of an infected tick or flea.  Symptoms can include fever, lameness, swollen lymph nodes, and inflammation of the inner layer of the heart.


Hepatozoonosis is caused by protozoan parasites of the genus Hepatozoon and is transmitted to dogs when they ingest an infected tick.  Symptoms can include fever, muscle pain, weight loss, and blood in the stool.

In conclusion, while ticks are small creatures, they can carry a variety of diseases that can affect your dog’s health. Therefore, taking preventative measures against ticks is crucial to protect your dog from these potential diseases.



← Older Post Newer Post →

Leave a comment


Lianne McLeod, DVM, is a former writer for The Spruce Pets, contributing articles for 11 years. Before Dr. McLeod began writing about pet care, she worked several years in small animal practice. She has written extensively about the care and keeping of exotic pets and pet health care. She now researches water quality and chronic disease at the University of Saskatchewan. Lianne McLeod earned her Doctorate of Veterinary Medicine from the Western College of Veterinary Medicine at the University of Saskatchewan. She also received a Bachelor of Science degree in biology from Simon Fraser University. She continued her education and received a Ph.D. in Epidemiology from the University of Saskatchewan. Now, she splits her time between her family, research and writing about pet health for all the animal lovers out there.
RuffRuff App RuffRuff App by Tsun