One of the most common and frequently mentioned tick-transmitted diseases in the world is Lyme disease. Although it does occur in both humans and in canines, Lyme disease in dogs looks very different than it does in humans.
What Causes Lyme Disease in Dogs?
Lyme disease is known to be caused by a spirochete (bacteria) of the Borrelia burgdorferi species. This particular spirochete is shared by a slow-feeding, hard-shelled deer tick known as Ixodes. When these ticks feed on mice or other small animals that are infected, they become infected themselves. If an infected tick bites people or other animals, it can transmit the bacteria to them.
The spirochete can grow in the gut of either the eastern black-legged tick, previously referred to as the deer tick (Ixodes scapularis) or the Western black-legged tick (Ixodes pacificus). Infection usually occurs only after one of the Ixodes ticks, carrying the spirochete known as Borrelia burgdorferi, has been attached to the dog for several hours.
Do All Dogs Bitten By a Tick Get Lyme Disease?
Just because a dog gets bitten by a tick does not mean it will become ill. This is true even if the tick is carrying the infected spirochete. Even among those dogs becoming infected, only a few of them, percentage wise will show symptoms and require treatment.
90% of dogs infected with Lyme will not develop symptoms requiring treatment. On the other hand, humans often develop serious symptoms. Often, humans with a Lyme disease infection have both signs and symptoms that last for many years. Lyme disease is often misdiagnosed in humans.
Signs and Symptoms of Lyme Disease in Dogs
When dogs do develop Lyme disease, the clinical signs and symptoms can be hard to distinguish from other viruses or illnesses. They can, and often do, include:
- Swollen, painful joints—dogs may be reluctant to move, likely from inflammation
- Lameness, or limping, which may be mild at first. It then worsens, and may also shift from one leg to another. This may last for days or for weeks. It is also known as “shifting-leg lameness”.
- Decreased appetite
- Swollen lymph nodes
- Stiff walk with an arched back
- Sensitivity to touch
- Difficulty breathing
Less Likely Symptoms But Much More Serious Ones:
Less likely, but still not rare, are kidney problems. The symptoms associated with kidney problems are serious ones. They include lethargy, loss of appetite, vomiting, and increased thirst and urination. Eventually, they may become unable to urinate at all. Dogs that develop kidney failure become very ill. Treatment does not always work and death may be the outcome.
Although more rare in dogs than in humans with Lyme disease, both cardiac complications and neurological disease do occur. Seizures and behavioral disturbances are the most common of the neurological symptoms of Lyme disease in dogs.
Where Is Lyme Disease Transmitted to Dogs?
Lyme disease has been reported in dogs throughout both the United States and Europe. The disease is spreading and becoming more common throughout the United States, with the exception of the southern and southwestern states. However, it is most commonly seen in the upper Midwestern states, the Atlantic seaboard and the Pacific coastal states.
Other Known Risk Factors for Lyme Disease in Dogs
Lyme affects dogs of all breeds, ages and sizes. Obviously, dogs that spend a great deal of time outside, especially in bush, areas of tall grass or in the woods are the ones most likely to become infected with Lyme disease. However, dogs can become infected anywhere ticks can be found. Remember, ticks can be carried into yards and homes by other animals.
It is not believed that Lyme disease is spread to humans through direct contact with infected animals. However, ticks on your pets can move on to the humans in your family. Lyme disease is much more dangerous to humans than dogs. It is important that you keep an eye out for ticks on your dog. Removing the tick in less than 48 hours minimizes the risk to your dog. It also minimizes the risk of Lyme disease to you and your family. The deer tick is small and may bite animals and people without ever being detected unless you are diligent in searching for them.
Is There a Tick Season?
Tick season is considered to be from spring through early fall. However, the time lapse between the infection and the appearance of Lyme disease symptoms can be from two to five months. It is easy to forget the tick you removed months ago if you are not careful to document it. It is wise to note the removal of potential disease bearing ticks on your dog’s health calendar.
How Is Lyme Disease in Dogs Diagnosed?
Just as with humans, the first critical step is to provide an accurate and detailed history of the dog’s health and past medical history. Your dog cannot complain directly to the vet so you must be able to share as much information as possible on his behalf.
Not only will the veterinarian need to know of any signs or symptoms that you have noticed, they need to know where your dog has been. Has your dog been exposed to areas where ticks known to carry the spirochetes responsible for Lyme disease reside? They need to know this as well.
Remember that they are also at risk for other common, tick-borne infections. In some cases, dogs can be co-infected with more than one type of tick-borne organism. Ehrlichiosis, Anaplasmosis, and Rocky Mountain spotted fever are all serious problems for dogs as well as for people.
Based on your dog’s symptoms, your veterinarian may recommend a number of tests. These could include:
- Chemistry tests to evaluate your dog’s kidney, liver, and pancreatic function, as well as his glucose levels
- Blood parasite screening to determine whether or not your dog has been exposed to tick-borne or other infections
- Quantitative Lyme antibody levels to monitor response to treatment
- Fecal tests to rule out intestinal parasites
- A complete blood count (CBC) to assess for blood-related conditions
- Electrolyte tests to ensure your pet isn’t dehydrated or suffering from an electrolyte imbalance
- Urine tests to evaluate the kidney’s ability to concentrate urine, to screen for urinary tract infections or other disease and to check for protein
- A thyroid test to determine if the thyroid gland is producing too little or too much thyroid hormone
- An ECG to screen for an abnormal heart rhythm, which may indicate underlying heart problems
- They are likely to draw fluid from the affected joints for analysis and to take X-Rays of the joints as well.
Some of the symptoms of Lyme disease in dogs resemble arthritis. There are many causes for such symptoms and your veterinarian will try to determine arthritis caused by Lyme disease from other inflammatory arthritic disorders. He will want to rule out such causes as trauma, degenerative joint disease and immune-mediated diseases.
So, What If It Is Lyme Disease? How Is It Treated?
If the diagnosis is Lyme disease, the treatment will depend upon how serious the illness is and upon your dog’s symptoms. Unless their condition is unstable and they need constant medical professional care, he will be treated as an outpatient.
Antibiotics Are First Line Treatment, But Which One?
Doxycycline is the first line choice of antibiotic prescribed for Lyme disease unless there are medical circumstances that dictate otherwise. Improvement in the inflammation of the joints caused by Borrelia should be seen fairly soon after the initiation of antibiotic treatment.
If there is no improvement within three to five days, your veterinarian will want to reexamine your dog and his choice of therapy. There are other dog antibiotics which are available and effective if the situation warrants a different therapy.
How long are antibiotics needed?
Although the most common length of treatment is a minimum of four weeks, longer courses may be necessary. Depending upon the severity of the case, your veterinarian may also prescribe an anti-inflammatory drug (pain medication for dogs). Appropriate selection and duration of treatment with antibiotics can minimize the risk of long term health problems.
Unfortunately, antibiotic treatment has not been shown to completely eliminate infection with Borrelia burgdorferi bacteria in all cases. Symptoms of the disease may resolve only to return at a later date. The potential development of kidney disease in the future is a major concern.
Can Lyme Disease in Dogs Be Prevented?
- Whenever possible, prevent your dog from wandering around in tick-infested areas, especially where Lyme disease is common.
- It is important to brush their coats carefully. This is especially true for dogs allowed to run in areas likely to be infested with the Ixodes ti
- Daily check your dog’s coat and skin for ticks and remove them as soon as possible. Remember that ticks must feed for at least 12 hours, and possibly 24 to 48 hours, before they transmit the spirochete that causes Lyme disease.
- Carefully remove ticks by hand and be sure none of it is left embedded in his skin. If you cannot determine the specie of tick removed, your vet should be able to identify it for you. Remember, not all tick species are carriers of the spirochete that causes Lyme disease in dogs or in people.
- If you live, or will be traveling, in an area where Lyme Disease is endemic, you may wish to be more proactive. You may wish to ask your veterinarian to prescribe a prescription flea and tick collar and/or topical and/or oral products that kill and repel ticks. Prescribed products should only be used with a veterinarian’s supervision. Be sure to follow the label’s directions carefully.
Vaccines, Pro and Con
Although their use is controversial, Lyme vaccines are available. Usually, Lyme disease in dogs is not a serious problem. You may need to talk to your veterinarian to decide if it is warranted. The potential risk inherent in any vaccine may or may not be worth taking in every case.
This is especially true if your dog already has an underlying medical condition. Anything that makes it more likely for your dog to have cardiac, renal or neurological complications of Lyme disease is worth discussing.
Potential Problems With Vaccines
Arthritis and kidney problems associated with Lyme disease are also, at least to some degree, related to the immune response to the bacteria, rather than the bacteria itself. Because of this, there is some concern that vaccination may contribute to these problems.
Also, vaccination is not 100 percent effective. Further, they are only helpful for dogs that have not already been exposed to B. burgdorferi. However, vaccinations given before exposure are thought to prevent dogs from getting Lyme disease. They may also prevent them from becoming a carrier of the bacteria.
When Are Vaccines Given?
If a vaccine is to be used, it is recommended to start vaccinating young puppies at around 12 weeks old. It should be followed up with a booster two to four weeks later.It must be given before becoming exposed to the spirochete to work at all.
The vaccine does not provide long-lasting immunity. Annual re-vaccination, ideally before tick season, is recommended for those choosing to vaccinate.
Here are a few steps you can take to prevent your dog from getting Lyme or other tick-borne diseases:
- If you live in an area where ticks are a serious problem, keep the grass and brush trimmed in your yard.
- You may also consider treating your yard for ticks.
- Ask your veterinarian about your dog’s risk of tick-borne diseases in your area.
- Obtain and use a veterinarian-recommended tick prevention product on your dog.
- Discuss with your veterinarian the pros and cons of vaccinating your dog against Lyme disease.
- Ask your veterinarian to conduct a tick screening at each exam.
- Watch your dog closely for changes in behavior or appetite as well as other known symptoms of Lyme disease in dogs.
- Check for ticks daily and, if one is found, remove it right away to limit infection.
Here are some tips for safe and effective tick removal:
- Wear rubber gloves to protect your hands.
- Grab the tick very close to the skin with a pair of fine-tipped tweezers. With a steady motion, pull the tick’s body away from the skin.
- Avoid crushing the tick to prevent infection.
- Carefully clean your dog’s skin with soap and warm water after removing the tick.
- Speak with your veterinarian about testing the tick before disposal.
- If having tested, save the tick may in a seal-able plastic bag in the freezer until taken to the vet. Otherwise, throw the dead tick away with your household trash or flush it down the toilet.
- Never use petroleum jelly, a hot match, nail polish or other products to remove a tick.
If you have any medical questions or concerns regarding your dog, you should always visit or call your veterinarian. They remain your best resource to ensure the health and well-being of your pets.