Lyme Disease in Dogs

What causes Lyme disease in dogs?

Lyme disease is a bacterial infection caused by Borrelia burgdorferi. This bacteria is carried by Ixodes ticks, commonly known as the “deer tick” or “black-legged tick”. There are four species of the Ixodes tick: I. scapularis and I. pacificus in the U.S., and I. persulcatus and I. ricinus in Asia and Europe.

Lyme disease can infect dogs, as well as people, horses, and possibly other animals. The tick must be attached to the dog for 24-48 hours for bacteria to be transmitted. This is why it’s important to remove ticks promptly if you find them attached to your dog (or yourself)! Spring and fall are when nymphs and adult ticks are most likely to transmit infection, as that is the time during which they are actively seeking hosts. Although they prefer to feed on deer, white-footed mice, and voles, they will gladly accept a dog or human as their host.

Although Lyme disease has been found in every single U.S. state, the Northeast (New England), Pacific Coast, and Northern Midwest have the highest number of cases. (Lyme is a town in Connecticut where the disease was first identified.)

How to Remove a Tick from Your Dog

If you find a tick on your dog, pull it off either using a tick remover tool (many pet stores sell these) or you can just use your hands and a tissue. You want to avoid any twisting or crushing, as this may force material out of the tick and into the bite wound.

Gently clean the area with soap and water and see your vet if it appears inflamed, swollen, infected, or concerning in any way. Avoid applying any ointments or oils to the area, as these can actually seal in any bacteria that tick may have been carrying.

Clinical Signs of Lyme Disease

There is a myriad of clinical signs which may or may not be present in dogs. Some dogs may exhibit no clinical signs whatsoever. Unfortunately, this does not mean the body isn’t being affected negatively by the bacteria. Be sure to contact your vet if your dog is experiencing any of these symptoms:

• Lethargy
• Painful and/or swollen joints
• Intermittent and/or limb-shifting lameness - Example: lame on the right front leg one day, lame on the left rear leg the next day, not lame at all the following day
• Fever
• Inappetence (decreased appetite)
• Swollen lymph nodes
• Untreated, Lyme disease can cause significant damage to the kidneys (usually fatal), heart (rare), and nervous system (seizures and facial paralysis).

Diagnosis of Lyme Disease in Dogs

Because Lyme disease may not cause any obvious clinical signs but can still be fatal, it’s important to test your dog every year for Lyme disease if you live in an endemic area, and 4-6 weeks after a known tick bite (any sooner may not give the body a chance to form antibodies against the bacteria, causing a false-negative test result). Most testing is done based on clinical signs or history.

In the clinic, your vet will test for the presence of antibodies to the Borrelia burgdorferi bacteria. This is just a quick positive-or-negative snap test. If the result is positive, this means antibodies are present, and your vet may send a more specific test to the lab to determine the approximate number of antibodies. A high number indicates an active infection is likely, whereas a low number may indicate that your dog was previously exposed (but maybe not currently infected with the bacteria). Some dogs may retain antibodies to tick-borne bacteria for several years after being exposed.

Treatment of Lyme Disease in Dogs

Four weeks of Doxycycline (an antibiotic) is the most common course used to treat Lyme and other tick-borne diseases (such as Anaplasma and Ehrlichia). If dogs have been showing clinical signs, they often perk up and improve in a matter of days, but it’s important to give the full course of treatment. If dogs aren’t treated, or treatment has been delayed due to unknown diagnosis or other complications, they may continue to have issues for life (chronic joint pain, compromised kidney function, etc.)

If specific organs are affected, more involved testing may be performed, and other treatments prescribed by your vet.

Prevention of Lyme Disease in Dogs

Monthly tick prevention is very important if you live in an endemic area. There are several oral and topical prescription tick preventions that your vet can prescribe for your pets. There is also a Lyme vaccine that is recommended for dogs in endemic areas or those who hunt or spend a lot of time outdoors and in nature. This is an annual vaccine that your regular vet will carry.

Is Lyme disease zoonotic?

It’s important to remember that Lyme disease is a bacteria transmitted (not caused) by ticks, and cannot be transmitted to you by your dog. But if you don’t treat your pets with monthly prevention, you may end up with ticks in your home and on your body!

Read more:

Lyme Disease in Dogs

Lyme Disease: A Pet Owner’s Guide

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