Table of Contents
How Infection Occurs
Borrelia is transferred in the saliva of infected Ixodes ticks (Blacklegged ticks) to the dog through a bite. A tick must be attached for 24-28 hours before the bacteria can be transferred.
When this bacteria enters the canine through a tick bite, the bacteria begins replicating within the skin. The bacteria can then spread to other tissues. The pathogen can cause clinical illness that is typically noted 2-5 months after the bite, although most dogs infected with Lyme do not show symptoms. Lyme disease can cause joint swelling, shifting leg lameness, fever, and lethargy. In more extreme cases Lyme can cause renal injury (Lyme nephritis), or nervous system abnormalities.
The exact mechanism behind the development of Lyme nephritis is not fully understood. Unfortunately, the majority of patients with nephritis do not recover due to the extensive kidney damage endured.
Symptoms of Lyme Disease in Canines
- Shifting limb lameness
- Weight loss
- Fluid accumulation
Testing for Lyme Disease in Dogs
There are several different ways of testing for Lyme disease in canines. Often routine screenings will be conducted by veterinarians annually while checking for heartworm infections. These types of tests check for antibodies against a surface protein
Borrelia carries. Having a positive serology test doesn’t automatically mean true infection, but can mean exposure to the pathogen.
If a patient tests positive for exposure to Lyme in a routine screening (C6 testing), additional diagnostics including a complete blood count, chemistry evaluation, and a urinalysis will likely be recommended. If there are abnormalities present on the lab work, or clinical signs are suggestive of possible infection, a confirmatory test will likely be done.
All dogs suspected of having exposure to Borrelia or exhibiting signs should have their urine evaluated as an early screening test for Lyme nephritis.
Common Laboratory Findings
- Decreased blood protein (hypoproteinemia)
- Elevated renal values (BUN, Creatinine, and SDMA)
- Proteinuria (protein present in the urine)
- Glucosuria (glucose in the urine)
- Urinary cast
- Possibly lowered red/white blood cells and platelets
- Elevated white blood cell count
This particular test quantifies the number of antibodies present against surface proteins found in Borrelia bacteria. This test is also used to monitor treatment success.
Joint fluid analysis, PCR testing, and cultures are other diagnostic options.
How to Treat Lyme Disease in Dogs
When a patient has been diagnosed with Lyme disease, an extended course of antibiotics, often Doxycycline, is administered for one month. There are some patients who may not respond well to Doxycycline, and as a result, other antibiotics like Amoxicillin or Cefovecin may be given. Dogs that have symptoms of Lyme disease will recover from symptoms quickly with appropriate antimicrobial treatment. It is difficult to say if a patient with Lyme disease can be cured, as clinical signs may reemerge from bacteria within tissues that were not previously cleared by antibiotics.
Fortunately, hospitalization is not typically necessary unless the patient has developed significant renal (kidney) complications and has become severely dehydrated.
Patients who develop Lyme nephritis have a guarded prognosis and are often euthanized due to kidney failure.
After a patient has been treated for Lyme disease, repeating a QuantC6 test is recommended to see if the number of antibodies have lessened.
How to Prevent Lyme Disease
Not only are ticks pesky, but they can also carry several different types of diseases in addition to Lyme. It is imperative to keep your pet on year-round flea/tick preventative. There are several different types of preventatives available, and your veterinarian can help you decide which product may work best for your companion.
Fortunately, there is a canine Lyme vaccination available that helps protect dogs against illness. This vaccination is typically administered in an initial two-part series, then boosted annually.
If you live in an area with high tick populations, you may consider treating your environment with appropriate insecticides. Speak with your veterinarian and local pest control to ensure you treat your yard with products that do not pose a risk to your companions.
Ticks enjoy shady environments and tall grass. They are attracted to certain types of foliage debris like pine needles. Cleaning your yard of accumulated piles of pine needles/fallen branches will help remove some of the ticks’ preferred habitats.
Risk of Human Transmission
Although people can develop Lyme disease, this cannot occur through direct contact with a dog or other animal that is carrying the Borrelia pathogen. In order for a human to develop Lyme disease, they have to be bitten by a tick carrying the infectious pathogen. In humans, often a “bullseye” appearance can be seen around the location of the bite. It is important to remove ticks quickly to lessen the chances of disease transmission. Your primary care doctor will be able to discuss risks, testing, and treatment options associated with tick exposure.
Although dogs do not directly transfer Lyme disease to humans, their outdoor activities can increase the exposure risk of a human to an infected tick. For that reason, it is imperative to appropriately protect your pet from ticks by having them on tick preventatives.
Yes. A patient can recover from Lyme disease with appropriate treatment. Most dogs with signs of lameness or lethargy can improve within 48 hours of antimicrobial therapy. Although the clinical disease may improve with antibiotics, some dogs with Lyme disease periodically become symptomatic again, and treatment may need to be repeated.
Unfortunately, dogs with Lyme nephritis have a significantly lower chance of survival due to irreversible kidney damage.
Exposure to Lyme disease is very common, however, not every dog who is exposed to the pathogen will develop clinical disease. Lyme has been reported in North America, Asia, and Europe.
Dogs who do not develop Lyme nephritis can have a normal life expectancy. Patients that have been treated for Lyme may experience a flare-up of clinical signs as some bacteria are able to remain in tissues following treatment. Recurrence of signs would warrant repeated treatment. Dogs that develop Lyme nephritis have a guarded prognosis.