Understanding Lyme Disease In Dogs

What is Lyme disease?

Lyme disease is caused by the spirochete (type of bacterium), Borrelia burgdorferi. It is transmitted to dogs through the bite of an infected tick. Once in the bloodstream, the Lyme disease organism is carried to many parts of the body and is likely to localize in joints or kidneys. The most common type of tick to carry Lyme disease is the deer tick, also known as the black-legged tick. Deer ticks are distributed through the midwest and the eastern United States.

Can Lyme disease also affect people?

Yes, but people do not get it directly from dogs. They get it from being bitten by the same ticks that transmit it to dogs. Therefore, preventing exposure to ticks is important for you and your dog.

What are the clinical signs of Lyme disease in dogs?

Many dogs infected with Lyme disease show absolutely no signs or symptoms at all. That is why screening for possible Lyme is important.

However, some dogs with Lyme are taken to a veterinarian because they seem to be experiencing generalized pain and have stopped eating. Affected dogs have been described as if they were walking on eggshells. Often, these pets have high fevers. Dogs may also begin limping. This painful lameness usually appears suddenly and may shift from one leg to another. If left untreated, the lameness may eventually disappear, only to recur weeks or months later. 

Non-specific signs which may indicate that Lyme disease is affecting the kidneys include vomiting, lethargy, anorexia (lack of appetite), and weight loss. The kidney form of the disease is less common, but it can often be fatal.

Most dogs infected with the Lyme disease organism take two to five months before they show symptoms. By this time, the disease may be widespread throughout the body.

How is Lyme disease diagnosed?

Dogs with lameness, swollen joints, and fever are suspected of having Lyme disease. However, other diseases may also cause these symptoms. There are a few blood tests that may be used for confirmation. The first is an antibody test that your veterinarian can perform in the clinic using a special test kit. This test detects the presence of antibodies created by exposure to the organism. A test can be falsely negative if the dog is infected, but has not yet formed antibodies, or if it never forms enough antibodies to cause a positive reaction.

It is recommended to test no earlier than four weeks after a tick bite. Some dogs that have been infected for long periods of time may no longer have enough antibodies present to be detected by the test. Therefore, a positive test is meaningful, but a negative is not. A follow-up test, called a QC6 test, can be done to assess the numerical antibody level as confirmation.

“It is recommended to test no earlier than four weeks after a tick bite.”

Other tests including PCR (polymerase chain reaction), ELISA (enzyme-linked immunosorbent assay), joint fluid analysis, and culture can also be done with varying degrees of sensitivity.

One test that can be performed is the SNAP 4Dx with proven C6 ELISA technology. This test detects C6 antibodies that are produced only as a result of the infection. It’s a simple test to complete, and results are typically available within eight minutes. While assessing the possibility of Lyme, the SNAP 4Dx also tests for heartworms, two types of Ehrlichia, and two types of Anaplasma.

General blood and urine tests are also often done to assess kidney function and to look for loss of protein in the urine.

How is Lyme disease treated?

Because the Lyme spirochete is a bacterium, it can be treated with antibiotics. The antibiotic of choice is doxycycline, followed by amoxicillin, then azithromycin. Treatment lasts for four weeks. Occasionally, the initial infection will recur, or the pet will become reinfected by being bitten by another infected tick.

How can I prevent my dog from getting Lyme disease?

One of the most basic keys to prevention is limiting your dog’s exposure to ticks. Ticks are found in grassy, wooded, and sandy areas. They find their way onto an animal by climbing to the top of a leaf, blade of grass, or short trees (especially cedar trees), where they wait until their sensors detect an approaching animal on which to crawl or drop. Keeping animals away from thick underbrush reduces their exposure to ticks. Dogs should be kept on trails when walking near wooded areas or places with tall grass.

Preventatives are also incredibly important, and whichever preventative option you choose for your dog, it should be used all year. Although many people believe ticks die out in South-Central Kentucky, that’s not true of all ticks. For example, the Brown Dog Tick is also known as the “friendly” tick because it comes indoors during the winter. 

There are several products available that can kill these ticks and prevent disease transmission. There are effective monthly preventatives that are chewables, which are easy to feed to most dogs. Two of these include NexGard and Bravecto. The Bravecto chewable comes in both a one-month and a three-month dose.

Another wonderful and simple to use product is a Seresto collar, which gives your pet eight months of protection simply from wearing the collar. 

Your veterinarian can advise you as to the best parasite control options for your dog; however, it is important to stress once again that preventatives should be used year-round. One important reason for this is because recent research has shown tick-borne diseases, such as Lyme and Ehrlichia, can increase a pet’s risk of developing chronic kidney disease.

Vaccination against Lyme disease is recommended for pets that live in endemic areas or that travel to areas where Lyme disease is prevalent. This vaccine is initially given twice, at two to four-week intervals. Annual revaccination is necessary to maintain your dog’s immunity. The decision to vaccinate against Lyme disease can be discussed with your veterinarian based on your dog’s lifestyle and individual risk assessment.

It is highly important to note that in our area of Kentucky in the past ten years, the prevalence of Lyme has almost doubled.

How do I remove a tick from my dog?

Check your pet immediately after it has been in a potentially tick-infected area. The deer tick is only about the size of a pinhead in its juvenile stage, but it is a little more obvious in the adult phase, especially after feeding. If you find a tick moving on your pet, the tick has not fed yet. Remove the tick promptly and place it in rubbing alcohol or crush it between two solid surfaces. If you find a tick attached to your pet, grasp the tick with fine tweezers or your fingernails near the dog’s skin and firmly pull it straight out. There are also tools available that can be useful. However, take care to use them cautiously as twisting or jerking the tick may cause the mouthparts to break off and remain in the skin. See your veterinarian if you are unsure or unable to remove the tick from your dog.

“…twisting or jerking the tick may cause the mouthparts to break off and remain in the skin.”

Make sure you protect your fingers from exposure by using a tissue or a disposable glove. You may need another person to help restrain your dog. Removing the tick quickly is important since the disease does not appear to be transmitted until the tick has fed for approximately 12-24 hours. If you crush the tick, do not get the tick’s contents, including blood, on your skin. The bacterium that causes Lyme disease can pass through a wound or cut in your skin.

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