By Robin Brennen
This may be more than you will ever need to know about ticks, but since I found a tick on my dog after a walk in Central Park, I think it is relevant information for New York City dog owners.
Although ticks aren’t the most loveable creatures, they just might be the hardiest—they have been around for over 100 million years. The oldest example is a 90 million-year-old bird tick in a piece of New Jersey amber from the Cretaceous period. It is likely that ticks will still be around long after humans are extinct.
Ticks are parasites that feed on the blood of their host, which can be an animal or a human. Ticks are sightless. They get around by using tiny pincer-like claws on the ends of their eight legs to grab onto rough surfaces. When a tick emerges hungrily from hibernation, it wanders blindly until it bumps into something, then grabs hold and starts climbing upward until it can rise no higher.
There, perched on some foliage, it sits patiently, using its legs as sensors that detect carbon dioxide and vibrations—it waits for its meal to drive by. It can wait for months. Ticks in various life stages can go well over a year without food.
Once aboard a feeding source, like your dog, they seem to navigate toward an area that is difficult to groom, like the ears or shoulder blades. Despite being quite hungry, they look for a mate. Male ticks remain on the host for an indefinite period of time, alternately feeding and mating. Usually, after a few matings he dies.
The females feed, mate, become engorged and then drop off to lay their eggs. The female dog tick lays 4,000-6,500 eggs. Then, exhausted, she dies. Adult ticks can sit around for two years waiting for food, then they eat, procreate and die.
The tick has a built-in spoon, fork and knife. The fork and knife dig a hole in the skin and, once the hole is dug, the spoon is inserted to feed. What is cool is that while digging, the tick secretes something akin to a topical anesthetic. It can take a half a day to dig the hole, and all the while the animal or human host doesn’t feel it.
Once they start sucking blood, ticks produce saliva that helps thin the viscosity of the blood, making the meal flow faster. The blood not only nourishes the tick, it also provides fuel to the bacteria living inside the gut of the tick. As saliva continues to be produced, some of the bacteria migrate out of the tick and into the host. This is how disease is spread.
Different ticks host different diseases. We are all familiar with Lyme disease carried by the deer tick, but the American dog tick can carry Ehrlichia and Rocky Mountain Spotted Fever. Both attack the blood cells of dogs and have been reported to cause disease in humans.
Protecting you and your dog from ticks takes diligence and insecticides! The Center for Disease Control recommends avoidance (walk in the center of a trail), repellents (check with your vet for products safe for your animals) and surveillance (body and clothing checks). Showering and bathing your dog can reduce the risk of being bitten. Ticks are susceptible to desiccation and high heat, so tossing clothing in the dryer can kill any hitchhikers that haven’t found their way to the flesh.
In addition to good tick control, you may consider vaccinating your dog against Lyme disease.
Robin Brennen is chief of veterinary services and VP of operations at the Animal Hospitals at Bideawee.
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