Nibbles and Bits — April 2011

Aside from some freakish and very non-springtime weather we’ve had, spring is actually here. It is appropriate, then, that April is Lyme Disease Awareness Month. Soon, everyone will be getting outside more, taking walks in the woods, the park, and down the street. During those walks, dogs love picking up things like sticks and leaves, but they also can pick up unwanted hitchhikers like ticks. Ticks do not fly or jump, but instead do something called “quest”. Basically, they wait around in the grass and leaves or on low brush and when something warm-blooded walks by, they grab a ride. Deer ticks are the ones primarily implicated in carrying the lyme disease organism (a bacteria called Borriella borgdorfori). This particular tick is very small, especially the early life stage called a nymph, which is about the size of the head of a pin. You can imagine how difficult it would be to find something that small on a dog’s coat, even if the dog has short hair.

Ticks do not stay on the dogs indefinitely. They attach to the skin using their mouthparts and stay for only a few days at most. They then drop off on their own to lay eggs. Most research indicates that the tick has to be attached for at least 24 hours and maybe as long as 48 to transmit lyme disease. Obviously, this means that if you do find a tick, you should remove it as soon as possible. The best way to remove a tick is to grab it as close to the skin as possible with a pair of tweezers and pull it straight out. You do not want to burn it, smother it in Vaseline or squish it with your fingers. All of those things can actually make the tick regurgitate and while we don’t feel sorry for the tick being a little queasy, the lyme bacteria is stored in the tick’s salivary system and when it regurgitates, it can inject the bacteria into the dog more readily.

Once the lyme bacteria is inside the dog, it can cause a number of different problems. The most common form of lyme disease affects the joints. The dogs suddenly become very lame, with swollen joints that are painful. They usually also run a fever and are lethargic. These dogs usually respond very well to antibiotics. There is also a very serious form of lyme called lyme nephritis that causes kidney failure. Unfortunately, dogs with this form often do not respond to antibiotics because the damage to the kidneys is irreversible. This form is usually fatal.

Luckily for dogs, it is usually very easy to diagnose lyme, unlike in people. We have a simple blood test that is run right in the office and takes about ten minutes. The vast majority of dogs that have lyme disease will show up positive on the test. This test also looks for heartworm, anaplasma and ehrlichia — the last two are also tick-transmitted diseases. We also recommend this test be run annually to screen dogs for exposure to lyme. If a dog tests positive for lyme and is not sick, we treat that dog anyway. A positive test means that the dog has the lyme organism in his body and may develop lyme disease. We also will often get a urine sample to test the kidney function since lyme can affect the kidneys. Unfortunately, many dogs that get lyme nephritis never show signs of lameness, so we hope that by finding these dogs early, we can prevent them from coming down with this devastating form of the disease.

We treat dogs that have lyme disease with antibiotics — usually either doxycycline or amoxicillin. If the dog is in pain, we also will put him on an anti-inflammatory medication. Dogs with lyme generally respond very quickly and feel better in 1-3 days. However, the antibiotics are continued for a month. With lyme nephritis, we have to treat the kidney failure, which involves hospitalization for IV fluids and monitoring of the blood work. Unfortunately, as was mentioned previously, many of these dogs will die even with intensive treatment.

Because of the potential seriousness of lyme, it is better to prevent it than treat it. There are several things you can do to prevent lyme in your pet. Firstly, keeping ticks off will stop lyme. Pull off any ticks you find as soon as possible. It is also important to use one of the topical tick preventatives. FrontlinePlus (for dogs and cats), Vectra3D (dogs only), Preventic collars (dogs only) and Revolution (mainly cats) are all good at killing ticks. The other important way of preventing lyme is the lyme vaccine. It is 85%-90% effective and very safe. It is initially a series of two vaccines, given 2-3 weeks apart and then annually thereafter. The vaccine actually works inside the tick to kill the bacteria before it ever enters the dog’s body. Once the bacteria is inside the dog, it hides from the immune system very well, which is why the vaccine was developed this way. The vaccine can be done at any age, but we recommend starting as a puppy because the vaccine is actually more effective if the dog has never been exposed to lyme before. We have also seen puppies as young as four months of age come down with lyme disease.

You’ll notice we did not discuss cats at all. That is because we don’t know much about lyme in cats. There is no test or vaccine for them and in fact we don’t really know what cats do if they get lyme. It is thought to cause intestinal signs such as vomiting but it doesn’t seem to cause joint issues. We do know it is not the common, potentially serious disease that it is in dogs, so you cat owners can breathe a sigh of relief over this one.

The threat of lyme disease should certainly not discourage you from spending quality time with your pet outdoors. However, it is important to recognize the risk and protect both your pet and yourself. Feel free to discuss this with us at your pet’s next exam or any other time.