Lyme Disease in Dogs

By Chelsea Hunt-Rivera / March 6, 2018
lyme disease in dogs

Ticks. Those blood-sucking, Lyme disease transmitting parasites! Enemies of man and canine alike. Is their existence necessary? Is there sole contribution to life on Earth the gift of spreading tick-borne illnesses? Whatever the answers to those questions, one thing is sure: they are here to stay. Of the many tick-borne diseases, Lyme disease is the most common in the US. Considering how common it is, all pet parents should understand Lyme disease in dogs and the potential dangers it could pose.


What is Lyme Disease in Dogs?

Lyme disease (also called Lyme borreliosis) is an infection caused by bacteria transmitted by a tick. The bacteria in question, the borrelia burgdorferi, are spirochetes. As the name suggests, they are spiral shaped bacteria (think cork screw) which enters your dog’s bloodstream when the tick feeds. The bacteria enters the bloodstream of their new host (your dog) and travels through the host’s body. Although the bacteria can settle in various places, it is commonly found in the synovial fluid of the joints, where it loves to cause havoc.

dog with lyme disease

Although it has been around for millennia, doctors did not identify Lyme disease until 1975. It was not until 1981 that borrelia burgdorferi was classified. In comparison to other medical conditions and diseases, there are many things about Lyme disease which are still unknown. It can be difficult to diagnose, and upon diagnosis, brings up more questions than solutions in terms of treatment options.

Whether in humans or dogs, Lyme disease is not your average “diagnose + treat” disease. Many dogs are infected but never develop symptoms of the disease. Most dog owners will never even know that their dogs have it. A healthy immune system can fight the infection off in many cases. It can however get quite serious for the infected dogs who do exhibit clinical signs of the disease. Joint pain, kidney disease, and even kidney failure are potential consequences of an untreated Lyme infection.

Lyme Disease in Dogs Causes

Deer ticks are the primary carriers of the Lyme disease bacteria. Let’s say an infected Deer Tick feeds on a mouse and infects it with borrelia burgdorferi. When the next Deer tick comes along and feeds on that same mouse, that tick becomes the next carrier of the bacteria and the cycle continues.

It’s Not Tick Bites…

The actual cause of the infection or the disease can not simply be ascribed to the tick-bite itself.

Many people think “tick-bite fever” when they hear Lyme disease. The tick and its bite are not culprits though. The real culprit is the bacteria which is transmitted from an infected tick when they feed.

Borrelia Burgdorferi

The root of the cause of Lyme disease is the transmission of borrelia burgdorferi from an infected tick to the “reservoir” host. Spirochetes live in the tick’s tummy. When the tick starts feeding, they make their way to the tick’s salivary glands. They then make the leap to the host via the saliva. This process takes around 24 -48 hrs after attachment. That’s why it is important to be on constant tick watch. If you take the tick off early enough, it lessens their risk of infection.

Once a dog is infected, the bacteria makes its way to all parts of the body. The skin, nervous system, joints and soft tissues are all at risk of being affected. With this said, only 5% – 10% of infected dogs will become symptomatic. A dog with a perfectly healthy immune system may fight the infection off, but a dog with a compromised immune system is worse off.

Dogs with weakened immune systems or other medical conditions often have a co-infection. This means they can suffer from multiple viral, fungal and bacterial infections simultaneously. Dogs that succumb to co-infection will most often show signs of Lyme disease. Spirochetes often localize in the joints nearest to the location of the tick bite. Once they are in the synovial fluid of the joint, they cause an immune response leading to inflammation within the joints. Enter arthritis.

In serious cases, Lyme disease can also cause Lyme nephritis, a type of kidney disease where bacteria attack the blood filters in the kidneys. This can be fatal. In very rare cases, Lyme disease is even believed to cause neurological issues or heart problems.

Lyme Disease Symptoms

In most cases, dogs infected with Lyme disease will not show any signs or symptoms of infection. Oftentimes, when a dog does show signs, the symptoms are mistaken for common symptoms of other diseases or illnesses. Identifying Lyme disease can be tricky. It only gets more complicated when your dog is dealing with a co-infection.

Luckily there are a few tell-tale Lyme disease symptoms that may show that your dog is one of the 5% – 10% of symptomatic dogs.

  • Arthritis – One of the most common clinical signs of Lyme disease is joint pain.
  • Recurrent Lameness – This happens because of the painfully inflamed joints. Your dog may appear to have a sore limb that stays sore for a few days and then gets better. Then, weeks or even months later, the lameness returns. Interestingly enough, it won’t always affect the same limb. We call this “shifting leg lameness” and it is a big Lyme disease red flag.
  • “Walking on eggshells” – If the infection has spread to multiple joints, a dog’s limbs may appear to be very stiff and their back arched.
  • Swollen Lymph Nodes – This can especially happen in the lymph nodes closest to wear the tick stuck its dirty little teeth into your dog’s skin.
  • Flu-like Symptoms including fever
  • Lack of Appetite and Weight Loss
  • Labored Breathing

7 Fun Facts About the Black-legged Tick (Ixodes scapularis)

ixodes scapularis

  • Western Black-legged ticks (also called Deer Ticks or Bear Ticks) have an average lifespan of two years.
  • They go through 3 life stages: larvae, nymphs and adults.
  • The larvae and nymphs feed mostly on rodents (especially the white-footed mouse) and the adults feed on larger mammals such as deer or bears.
  • Deer ticks are more abundant and common in the Pacific Coastal states, Midwestern states, and the Atlantic Seaboard.
  • Lyme disease is present in just about every state of the US and the numbers are growing. We can thank global warming for that one. With the rising temperatures and mild winters, rodent populations are thriving and with them, the ticks with their diseases.
  • Ticks do not all die in winter. It is true that Lyme disease skyrockets from Spring to Fall, when the weather is warmer, but ticks are active in any temperature that is above freezing.
  • The number of ticks infected with borrelia burgdorferi ranges from 30% – 90% in endemic areas.

Dogs with a Higher Risk of Getting Lyme Disease

Many dogs may have Lyme bacteria in their system without the infection ever becoming a problem. There are of course factors which increase a dog’s likelihood of becoming symptomatic.

  • Seroprevalence – The risk of a dog getting Lyme disease is increased in areas with larger populations of infected ticks. Lyme disease is spreading all over the US, but in certain states the numbers of infected ticks and hosts are much higher than in others. A dog in New York has a much higher risk of getting Lyme disease than one living in Colorado.
  • Breeds – Sadly, there are certain breeds that are more likely to get Lyme disease. The disease also has a much harsher and damaging effect on them. Golden Retrievers, Labrador Retrievers, Bernese Mountain Dogs and Shetland Sheepdogs fare worse than other breeds when dealing with Lyme disease.
  • Age – Young puppies are more susceptible to developing Lyme disease.
  • Compromised immune system – A dog with a compromised immune system or an autoimmune disease has a very high risk of developing the symptoms of Lyme disease. Dogs with weak immune systems are the ones who usually have some combination of co-infection with Lyme disease and other diseases or infections.

The Difficulty of Diagnosing Lyme Disease in Dogs

difficulty of diagnosis of lyme disease

Lyme disease is relatively easy to diagnose in humans. An obnoxious and difficult to miss “bull’s eye” forms around the area of the tick bite. It can take anything from a couple of days to a month to form. With dogs, the diagnosis is not nearly as simple.

Most dogs infected with borrelia burgdorferi don’t become symptomatic. There are next to no studies on the effects on a dog’s health after long term infection of the borrelia burgdorferi.

Some dogs exhibit signs of Lyme disease, but the signs are common symptoms of a long list of more likely illnesses. A veterinarian trying to diagnose a dog will often do so by a process of elimination. Lyme disease is one of the last boxes to check. In the case of a co-infection, the veterinarian is more likely to miss the Lyme disease, diagnosing the other infection instead.

Another problem with diagnosing Lyme disease in dogs, is that the disease can have delayed symptoms. The symptoms can surface up to a year after infection. It may appear that your dog has suddenly developed lameness in their limbs overnight when in fact, it is the result of being infected by a tick months ago.

Lyme Disease in Dogs Testing

There are many tests a veterinarian can perform to help making a diagnosis. Unfortunately, the tests for Lyme disease are pretty useless a lot of the time. Two of the most popular tests are the antibody test and the Polymerase Chain Reaction (PCR) tests.

It seems like a no-brainer to check for antibodies when trying to identify whether or not there is an infection. There are, however, a few problems with counting antibodies to test for Lyme disease in dogs. The dog may have been infected for a long time or have a compromised immune system and therefore, may not have many antibodies. The test can also come up as a false negative if the dog has the infection but its immune system has not yet responded to it. Again: not enough antibodies to check the “infection” box.

The PCR test is a little more promising (but not perfect). Spirochetes are not always found in a dog’s blood system because they generally prefer to hang out in connective tissues such as cartilage. For a PCR test, the veterinarian will draw fluid from a dog’s joint for analysis because they are more likely to find borrelia burgdorferi.

Is Lyme Disease Curable?

Like with all Lyme disease questions, there is no absolute answer that can be confidently backed up by science. If the infection is detected in a dog, it can certainly be treated and managed. Unfortunately, in many cases, Lyme disease will stay for life. Re-infection is also always a possibility, especially for dogs with a higher risk of contracting the disease.

Lyme Disease Treatment

lyme dieases treatment

Lyme disease really is a strange one. On one hand, a dog diagnosed with Lyme disease who shows no symptoms will almost never be treated by a veterinarian. On the other hand, dogs may experience potentially fatal manifestations, a reason for every pet parent to seek treatment for their dog should they become symptomatic.

Treating Lyme Disease in Dogs with Veterinary Medicine

Lyme disease in dogs, as well as in humans, is generally treated with antibiotics. The good thing about the antibiotic treatment is that dogs with severe symptoms respond very quickly to it. Yay!

But of course, once again, there is a downside: the treatment period is long. Very long. Treating Lyme disease with antibiotics such as Doxycycline is not a 5-day thing. The treatment requires you to give your dog antibiotics for at least a month, if not longer. And then, even after medicating your dog for a month, the infection can resurface or return. Between cost and long-term effects of prescription meds, this treatment plan (understandably) does not go down well with many pet parents.

The Lyme Disease Vaccine Controversy

Most dogs and people who have Lyme disease fight the infection without even showing symptoms. But are there dogs that should get the Lyme disease vaccine? Vaccinations are a controversial topic on the best of days, but the Lyme vaccine takes it to a whole new level. The Lyme vaccine, like all things “Lyme disease”, is a very hard sell. Understandably so. The human Lyme vaccine was only on the market for a few short years before authorities removed it after a lot of bad press.

The episode with the human Lyme disease vaccine does little to inspire pet parents to give it to their dogs. On top of that, pet parents need to ask themselves what the point of vaccination is when they can manage the disease with medication and lifestyle changes.

This is where people need to do their homework and make an informed decision based on each individual dog’s risk assessment.

How to Prevent Lyme Disease in Dogs

Preventing Lyme disease is pretty easy. Whether you believe in the power of modern medicine, homeopathy, or all-natural remedies, there is something for everyone. Not only will you be preventing Lyme disease, you will be preventing a bunch of other tick-borne illnesses as well.

Avoid Tick Infested Areas

Ticks live in trees, long grass, underbrush and sandy areas. Avoid taking your dog to those areas, especially during the warmer summer months when those suckers are more abundant and active than ever.

Check Your Dog for Ticks Daily

checking your dog for fleas

Sometimes tick infested areas are hard to avoid, especially when it’s warm and sunny and outside weather every day. Check your dog for ticks daily. In order for the Lyme bacteria to enter your dog’s bloodstream, the tick has to be attached to your dog for 24-48 hrs. If you check for ticks daily and remove them, there will be little chance of infection.

It’s very important to read up on how to remove ticks. If your dog is a tick magnet, chances are you’ll be doing it a lot. It is better to know how to do it correctly and safely if it’s an every day activity.

Be sure to wear gloves if you have cuts or wounds on your hands. Spirochetes can enter your system easily from a crushed tick’s body through an open wound in your hand.

Tick Control

This is probably the most important preventative step that every pet parent should take seriously. It does not matter whether you think that tick control pharmaceuticals are poison. Or if you think that using citronella smells weird. Tick control is a must.

Know the difference between something that repels ticks and something that kills them.

There are flea and tick pharmaceuticals which have a bad rep (due to hysteria more so than fact), which are not only safe for your dog, but will kill every flea and tick within a couple of hours, long before any tick-borne disease infects your dog.

Whatever you go with, monitor its efficiency, and if it doesn’t work, try something else.

Never underestimate the importance of tick control, regardless of whether you are Team Citronella” or Team Bravecto.

Lyme Disease Vaccine

lyme disease free dog

If you worry about your dog getting Lyme disease and don’t have any issue with vaccines, speak to your vet about the Lyme vaccine. For a dog living on a farm in an area where there is a seroprevalence of 90%, it may be worth it.

If your dog, however, lives mostly in your apartment, and occasionally travels with you in your handbag, there is probably no need for it. Your vet will be able to assess the risk based on your lifestyle and your dog’s health.

You honestly don’t have to read and memorize the entire Merck Veterinary Manual to prove that you are a good doggo parent. What matters is knowing enough about Lyme disease to know when to take your dog to the veterinarian. Never underestimate the importance of tick control, regardless of whether you approach it holistically or pharmaceutically.


Illustrations inspired by our furry friend Waish!


Is there a cure for Lyme disease in dogs?

Are there any dogs that are more susceptible to Lyme disease?

Lyme disease is caused my tick bites, right?

Is there a vaccine for Lyme disease in dogs?

What is a deer tick?






About the author

Chelsea Hunt-Rivera

Chelsea Rivera is a Dedicated Pet Parent who loves to create amazing content for pet owners and is helping change pet wellness as the Head of Content for