Ticks – Menace or Myth

Dogs

Perhaps no feeling gives humans the creeps like the that of finding a tick crawling on them and the same applies when they find a tick on their dog. There is frequently hysteria about the blood sucking habits of ticks and the diseases they can potentially transmit to us and our pets. But are they really a menace or are they so shrouded in myth that we can’t see that they are just arachnids going about living their lives?

The Western black-legged tick, Ixodes pacificus, is the main species of tick found on Vancouver Island. There appear to be two main tick seasons for many areas of Vancouver island, a spike in the winter months of January and February and another during the summer, May through July. In the nymph stage ticks need blood meals to complete development (nymph to adult) and as adults, the blood meal provides a protein source for producing eggs. Either stage can feed on a host of animals, including deer, rabbits, mice, dogs and humans and even reptiles, such as the alligator lizard. Cats appear to remarkably good at grooming ticks off their bodies thus we seldom see ticks in cats.

Humans and dogs generally encounter ticks in grassy, brushy and wooded areas when the ticks are questing for a host. “Questing” is the term used for the way in which a tick crawls out onto the tips of vegetation with some of the eight legs hanging onto vegetation while the other legs hang out in the air waiting for the host to brush next to them and then they grab onto the host. The most common locations where tick are found on dogs are the head and upper front torso of the dog, simply because these are the areas that are the first contact points as a dog moves forward through the brush.

Once on the host they select an area of skin and will start to take a blood meal. Contrary to myth, the head of the tick does not get buried in the skin, in fact only two small mouth parts actually penetrate the skin and to hold on, they secrete a biological glue called “cementum” from glands in their body. Secured firmly in the skin of the host, the mouthparts tap into capillaries and the long slow process of taking a blood meal begins. Full engorgement can take up to 48 hours and a tick may attain the size of a pea. Once full of blood, and ready to release, the tick secretes a digestive enzyme from the gut which dissolves the glue and allows the tick to pull out the mouthparts and drop off the host. It is during this last phase that disease producing bacteria are released into the blood stream of the host and infection can occur. Thus, if your find tick when it is small and flat and before it fully engorges, it is unlikely to had time infect your pet.

Fortunately, on Vancouver Island, Lyme Disease, caused by the bacterial Borrelia burgdorferi, is rare in dogs and people, and it has proven to be difficult to definitively diagnose. Blood tests may help determine the presence of disease and the general course of treatment, if the disease is suspected in dogs, is one of several antibiotics. Prognosis for recovery is good if treated, yet many dogs may also recover without treatment. The mains signs of Lyme disease in dogs are lethargy, inappetence, stiff joints and lameness, fever and swollen lymph nodes. There is also an annual vaccination against Lyme Disease in dogs and it is often recommended by veterinarians for dogs whose lifestyles put them in higher risk of tick bites in areas where Lyme disease is present.

Another tick borne disease that has been recorded more recently on southern Vancouver Island is a rickettsial bacteria called Anaplasma. This organism produces many of the same signs of disease in dogs as seen in Lyme Disease and the organism can create signature changes to platelet counts, red cell counts and even be seen in white cells on a blood smear. This organism can be treated successfully with a course of antibiotics.

Your dogs has a generally low risk of getting either disease on Vancouver Island, but the diseases can be serious therefore it is worth taking steps to avoid being bitten. There are several safe veterinary prescription flea and tick prevention products that are very effective in killing ticks before taking blood meals or just after starting to take a blood meal, and thus can greatly reduce tick borne diseases in dogs. Advantix and Revolution are topical medication applied monthly to the skin of dogs. Newer generation flea and tick products such as Bravecto and NexGard are perhaps the most effective prevention medications and both are oral chew tabs. One Bravecto chew tab gives three months of tick control, while NexGard is given monthly. Bravecto is also a very effective off-label treatment for eliminating mites, the tiny cousins of ticks; specifically Demodex and Sarcoptes mites, which cause two forms of mange in dogs.

If you find a tick on your dog the most effective way to remove them is with tick twisters, tick pullers or tweezers available at vet clinics and pet stores. Pull the tick straight out from the skin and try not to squeeze an engorged tick. Using vaseline, matches, kerosene, alcohol etc., are generally not effective and may harm your pet. The small firm bump in the skin that is left behind after pulling out the tick will eventually regress, but if an area of spreading redness develops then consult your veterinarian as this could be a sign of bacterial infection.

So generally, it could be said that yes there is a gross out factor for humans with ticks, but note that your dog may seem completely unaware it has a tick on it. By using effective tick prevention medications, close checking of your pet and tick removal after hikes in the bush, the risks of developing illness are fairly low here on Vancouver Island. Consult your veterinarian if you are finding many ticks on your pets during tick season and place them on a preventative medication.