Tick Diseases

If you live in New England, you are aware of the fact that we have a tick problem. When most people think about ticks, they think about Lyme Disease. However, there are two other tick borne diseases that we are seeing more frequently in pets. These other tick borne diseases that are becoming more common are Anaplasmosis and Ehrlichia. Although cats can get Lyme Disease, Anaplasmosis, and Ehrlichia, it is less common since they are fastidious groomers and often remove ticks before they have time to attach. For the purpose of this article, I’m going to focus on these diseases in dogs.

Lyme Disease is most commonly spread by the deer tick and is caused by the bacteria known as Borrelia burgdorferi and other emerging sub-species of Borrelia. Clinical signs of Lyme disease include fever, swelling of joints, shifting leg lameness, decreased appetite and Lyme Nephritis. Lyme Nephritis occurs when the kidneys have long term exposure to Borrelia, which causes an immune reaction within the kidneys. As the body is trying to fight the Borrelia organism, it creates antibody complexes which get deposited within the kidneys and causes damage. As a result, the dog’s body may start losing protein through its kidneys, which can be life threatening and eventually lead to renal failure.

Ehrlichia Canis and Ehrlichia Ewingii are the two most common species of Ehrlichia that affect dogs. Ehrlichia attacks the white blood cells and platelets in dogs and is transmitted by the brown dog tick. There are three phases of infection that occur in dogs when they are infected with Ehrlichia.

The first phase is the acute phase and occurs 1-3 weeks after the tick bite. During this phase the Ehrlichia organism will attach to the dog’s white blood cells and cause the dog’s platelets to drop. Clinical signs during this phase include lethargy, lymph node swelling, and decreased appetite or anorexia. If treated during this phase, infected dogs usually recover. If they go untreated, they will move on to the second phase which is called the subclinical phase.

During the subclinical phase, dogs will often appear normal. The Ehrlichia organism is living in the spleen at this time. Dogs can harbor the organism in their spleen for years and may never progress to the chronic phase. There may be clues on bloodwork that the dog is harboring the Ehrlichia organism in its body.

The final stage is the chronic stage. In this stage the dog will become sick again. Dogs in the chronic stage will often have abnormal bleeding due to low platelet numbers. Other clinical signs include deep inflammation, uveitis, a severe decrease in white blood cells and possible renal involvement. This stage of the disease can be fatal.

Anaplasmosis is another tick borne disease that has become more common over the last decade as well. It is also spread by the deer tick as well as the black legged tick. Anaplasmosis affects platelets and white blood cells just like Ehrlichia. Anaplasmosis has similar clinical signs to Ehrlichia. The clinical signs are often vague and can include fever, lethargy and decreased appetite. It can also cause bleeding issues.

The good news is that all of these tick borne diseases are treatable with antibiotics. Early detection and treatment is often key. Most veterinarians will test their canine patients annually for the three tick borne diseases mentioned above. Based on those results and what the current recommended protocol (which is constantly changing as more research is being done) is, will determine what the next step for your dog is.

The good news is that for Lyme disease there has been a vaccine available for dogs for years. Through advances in research, the vaccine has evolved and is very effective. Nothing is 100% though, and there are no vaccines for the other tick borne diseases. That is why it’s a good idea to have a really good tick preventative. There are many tick preventatives available over the counter and through your veterinarian. They are not all created equal. Many over the counter products have been around for decades and may not be the best choice for your pet. Which tick preventative is best for your pet should be discussed with your veterinarian.

Another common misconception is that it takes 24 hours or more for a tick to transmit diseases to your pet. The latest research is showing it takes less than 8 hours to transmit tick borne diseases, so it is very important that whatever tick preventative you use has a quick killing time. You should also use tick prevention year round. Ticks are not just a spring time or fall issue. They are not out every day of the year, but they are out every month of the year. For the last three years I have picked ticks off of my patients every month of the year.

Tick borne diseases can be fatal, but when detected early their damage can often be reversed or prevented. With annual tick testing, appropriate vaccination for at risk dogs, and good tick prevention, many tick borne diseases can be prevented.

If you want to know what tick borne diseases are being seen in your county go to www.capcvet.org where you can look at prevalence maps. Veterinarians that do the annual testing and report the results contribute to the data on these prevalence maps.