Ticks and Tick-Borne Infections and Diseases in Dogs
By Emily Hoppmann, DVM
One of the most commonly seen parasites in veterinary medicine is the tick. Many people think ticks are insects; however, the tick is considered to be part of the arachnid family (this family also includes mites, spiders, and scorpions). Most ticks complete 4 life stages: egg, six-legged larva, eight-legged nymph, and then adult. Ticks are external parasites that prey on the blood of mammals, birds, reptiles, and amphibians. In order to survive, they must eat a blood meal from a host animal during each life stage. Some tick species have extremely long life-cycles— even up to 3 years in several different species, but most will die early on due to the inability to find a host. Although there are approximately 15 different species of ticks in North America, only a few species are likely to be encountered by your dog. The most familiar tick species seen on dogs include: Deer Ticks, Western Black-Legged Ticks, Black-Legged Ticks, Lone Star Ticks, American Dog Ticks, and Pacific Coast Ticks.
Ticks are very clever when it comes to finding and attaching to our pets’ skin. It is a common misconception that ticks only live in areas that are wooded—this is false. Ticks live on the ground no matter what the surrounding environment is. The tick is not able to jump or fly, so to gain access to their hosts, they simply climb up the animal itself, or they climb to a high point (a blade of grass or the leaves of bushes) and then reach out to grab onto a passing dog or other host. Often times ticks can detect a passerby way in advance by scent or other sensory indicators such as body heat, moisture, and vibrations. These specialized sensing abilities allow them to position themselves quickly and efficiently. Some ticks will attach to their host and embed quickly, while others will wander to find warm areas that have thin skin—such as around the ears and on the head, in the armpits, and in between the digits on the toes. Most ticks will head to the highest point on a host, so that is why you often find them on the head of your pet.
In many regions of the United States, ticks are most active from the beginning of April well into the fall months (as late as November). However, the Southeastern United States (WV, VA, KY, TN, NC, SC, GA, FL, AL, MS, AR, and LA) are known to experience year-round tick problems due to the constant warm weather. Also even when it does freeze over or temperatures drop to the point we consider it cold, these temperatures don’t bother certain tick species at all, allowing them to thrive all year and cause infections year-round. Some ticks are even able to make a type of antifreeze to survive during the winter months. The tick that is the least affected by cold weather is the Deer Tick. While some ticks go dormant during cooler weather (though the weather in this area hardly is considered cooler weather for most ticks), the Deer Tick can remain active throughout any winter day that the ground is not snow-covered or frozen; and then even after a thaw, these ticks can become active again. We all know that in the Southeast the ground is rarely snow-covered or frozen, so Deer Ticks do very well here and these ticks are also masters at finding a nice warm spot (such as our homes or covered outdoor areas) to lay in wait if it does get a bit chilly. Also in the winter, ticks will move indoors and that puts them in even closer contact with pets and people. This is why it is important to keep our pets protected from all parasites (fleas, ticks, mosquitoes, biting and sand flies, and biting and sucking lice) year-round and to be sure that our dogs are vaccinated against Lyme disease, the most common disease that we see in our area.
It is important to remember that all ticks are at risk of carrying diseases, which in turn means that our pets (and ourselves!) are at great risk when bitten, which is why it is so important to have your pet vaccinated against Lyme disease. Tick-transmitted infections are more common these days than in past decades. With unbelievable increases in human populations and commercial development, the habitats in which wildlife can live and survive are getting increasingly smaller. Wildlife now has far less choices in where they can reside, which simultaneously invites the large number of infectious parasites that prey upon them to be transmitted to our pets since they are living in closer proximity. Due to these trends in our communities, the increasing abundance and geographic spread of tick species, is at an all time high. Furthermore, researchers are finding an ever increasing list of disease causing microbes transmitted by these ticks. What used to just be an annoyance, has now become a major health concern among both the medical and veterinary communities. Since some of the diseases that these ticks carry can also infect you, you need to remove the tick in the best fashion to avoid increasing the likelihood of infecting your pet and yourself. You do not want to use a lit match, fingernail polish, or petroleum jelly to remove a tick because this can actually result in the tick depositing more disease-carrying saliva into the wound, increasing the risk of infection. You always want to wear rubber gloves and use tweezers to grasp the tick as close to the skin as possible and pull the body out with a steady motion when removing them from your pets. You will want to clean the skin where you removed the tick with soap and water after removal and dispose of the tick by placing it in alcohol to kill it before discarding it.
Ticks can transmit a number of diseases to dogs and people. These include Rocky Mountain spotted fever, anaplasmosis (sometimes known as “dog fever”), ehrlichiosis, and some emerging diseases with potentially devastating effects. Among the diseases that ticks can carry, Lyme disease is by far one of the most well-known tick-borne diseases affecting not only dogs, but also cats, many wild animal species and human beings. Lyme disease is most common in dogs out of all of our pets and in the U.S., Lyme disease has been reported in every state; therefore, no region in the country is safe. It has been studied that dogs that spend the majority of their day outdoors are more likely to be bitten and infected by a tick-borne disease. Lyme disease is very close to my heart because I have close friend that contracted Lyme disease from a tick bite back in the early 1980s and this has resulted in a life-long battle with this disease. Lyme disease in dogs most often causes recurrent acute arthritis with lameness, but can also frequently cause fever, anorexia and depression. There are also more serious consequences of Lyme disease, which can include heart, neurologic, and kidney disease/failure. We are able to do in-house testing for several tick-borne diseases, including Lyme disease, to ensure your pet is not infected even if you have not seen any clinical signs yet so that we can treat the infection as early as possible. In the early stages of the disease, in people and pets, often there are no symptoms experienced. The recurrence of clinical signs is one of the worst things about Lyme disease since a patient can respond wonderfully to antibiotic treatment initiated when clinical signs are present, but then the disease can sometimes stay in the body and cause flare-ups at random times in the future. Therefore, vaccination and monthly tick prevention is the best way to avoid contracting the infection at all and taking the chance that your pet may develop a life-long illness from this preventable disease.