Tick Talk

Article ID: 527411

Released: 20-Feb-2007 11:00 AM EST

Source Newsroom: Thompson Rivers University

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Newswise — Ticks: They lurk in the tall grasses, waiting for the unwary; when they detect carbon dioxide or vibrations from walking animals, they hurry up to the top of blades of grass, where, with their heads down, they wave their legs hoping to catch a ride on a host.

A not-so-welcome harbinger of spring, ticks rank with leeches as one of the least desirable animals to discover attached to any body. Distinct from the true insects in that they lack antennae and possess four pairs of legs as opposed to the three pairs of all insects, ticks are arthropods that are close relatives of spiders. Their distinctly spider-like appearance is not an attribute that gains the sympathy of many people, and their presence is clearly not to anyone's advantage. However, as spring arrives, animals, humans included, that spend time in the grasslands will once again become acquainted with this tenacious animal.

Although a few of them would fit on the average person's fingernail, the fear and loathing they engender is huge; and just as in the old Kipling poem, the female is deadlier than the male. But not to worry: most aren't that dangerous for humans, says Thompson Rivers University biologist Rob Higgins.

Higgins, an entomologist who specializes in ants, hastens to say that he's no major expert on ticks.

"The only real tick expert in the province of British Columbia was Jack Gregson (to whom TRU gave an honorary degree a few years back) but Jack died in 2006. The only other person with some tick knowledge is Dr. Mohammed Morshed with the BC Centre for Disease Control (CDC) but he hasn't done any field collecting for a long time," he explains. "I'm unofficially considered as the most knowledgeable about ticks in the Cariboo-Chilcotin, but that is only because everyone else knows nothing," he grins. He knows enough to set the record straight on a common misconception, however: "Even if it feels like it, ticks don't burrow into the skin," he says.

"What the tick does is secrete a whitish cement-like substance around her head and jaws to hold her onto her host," he explains. "It is this substance that often causes many people to mistakenly believe the ticks are burrowing into their skin, something ticks do not, and cannot do."

In fact, says Higgins, if left alone, the tick will drop off her host after several days and search for another host to complete the next stage in her life cycle. Of course, this knowledge doesn't help if the tick is one of those that cause paralysis or disease, or if you're confronted with hordes of the little parasites, which can happen with some species.

"While a human might pick up a handful of individuals of the Rocky Mountain wood tick on a bad day, because of the way the winter ticks cluster together on plants, a host usually picks up a very large number. It is not uncommon to have up to 30,000 ticks on an animal and I personally found several thousand on a horse I brought in from out west," says Higgins.

Higgins has some advice for those who find a tick.

"When removing a tick never use chemicals or burn it with matches," he cautions. "Irritating a tick in this manner will only make it more likely to release potentially dangerous microbes into its host. Rather, simply grasp the tick's body firmly, top and bottom, in a pair of tweezers and gently pull back. A gentle but firm pull should remove the tick in about half a minute."

A person might need a pretty small pair of tweezers when dealing with ticks of the genus Ixodes, which are, says Higgins, "about the size of a sesame seed and thus easy to overlook."

Their effects can be quite noticeable, says Higgins. "Their bite can be quite painful, and they can carry the bacterium Borrelia that is responsible for Lyme disease.

"Fortunately, the species of this tick, Ixodes pacificus, or black-legged wood tick, that is the usual carrier of Lyme disease, does not appear to live much north of Boston Bar. We have two species of Ixodes here in the Cariboo-Chilcotin but neither seems to like humans as a host."

Hard-bodies ticks of the genus Dermacentor include the winter tick mentioned above and the Rocky Mountain wood tick, which is the tick that most people encounter, and which can be dangerous, depending on where it's found.

"While this species is known to carry the bacterium Rickettsia that causes Rocky Mountain spotted fever, ticks on the western side of the Rockies do not appear to carry this disease," says Higgings. It can, however, cause other problems, he cautions. "On rare occasion this tick can cause paralysis in her host which can lead to death unless the tick is removed, but fortunately the removal of the ticks will completely resolve the paralysis," he added.

While the winter tick doesn't carry disease, a large quantity can cause serious energy loss in deer, elk and moose struggling with poor winter-feeding conditions, says Higgins, who explains that "As the animals rub against trees or other objects to dislodge these ticks they lose a significant amount of hair. The name 'ghost moose' was coined to describe moose in this condition."

Higgins has some final advice for people going out on the trail during tick season:

"You can keep ticks from crawling under clothing by wearing a long-sleeved shirt, long pants, and boots or sturdy shoes, and by tucking pants cuffs into socks or taping up gaps where pants and socks meet," he says. "Check yourself and your animals after a walk in the woods or grasslands, and if you have an unexplained illness with fever, call your doctor and be sure to let him know if you've been in places where you may have picked up a tick."


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