Epidemiologist concludes deer are bringing arachnids into the city
Ticks, the blood-loving springtime menace of Montana's backcountry, have moved to town, state epidemiologist Todd Damrow said Monday.
He knows because he found one on the bedspread in his Helena home. "And no one had been out of town or in the woods."
And while he doesn't want to cause panic, Damrow does want Montanans to "be aware and expect to encounter ticks in places they aren't used to encountering them."
Damrow's interest is in preventing the diseases carried by ticks: Rocky Mountain spotted fever, Colorado tick fever, tularemia and Q fever. (Ticks in Montana do not transmit Lyme disease, as do ticks in the eastern United States.)
About a dozen cases of Colorado tick fever, a relatively mild ailment, are reported in Montana each year. Spotted fever is less common, about a case every other year, but can be fatal if left untreated.
Ticks likely came to town aboard Montana's growing population of urban deer, Damrow said. "It just kind of makes sense. Where you get known tick hosts, you're going to get ticks."
And these days, deer are plentiful in many Montana cities and towns. "We've even had deer on the Capitol grounds, including bucks squaring off against one another," he said.
This is the first year that Damrow's had evidence of urban ticks, although he conceded that no one from his office has actually been out looking. But after receiving two in-town ticks in the mail - "for identification purposes" - he decided to put out the alert.
"Seeing as how tick bites are very preventable, we want people to be aware of their presence," he said.
Thus this primer: Spring is the season when ticks "crawl onto low vegetation and wait for people or animals to brush up against them," Damrow said.
Ticks do not jump or fly. They climb into the grass or onto bushes and wait with their front legs outstretched until someone - or something - walks by. They use the claws at the end of their legs to hook onto threads or fur. The "host" passes by; the tick hooks on.
Ticks are arachnids, not insects. That means they're related to spiders, mites, scorpions and horseshoe crabs. They are also "obligate blood feeders." Unlike mosquitoes, which will take an occasional sugar meal, ticks only feed on blood.
What's amazing to Damrow is that the ticks Montanans actually see are on their third blood meal. The Rocky Mountain wood tick, the variety most common in these climes, is a "three-host" tick.
As a larvae, a fresh-from-the-egg baby tick, it feeds on small mammals like mice and ground squirrels. Engorged, the tick drops back to the ground and develops into a nymph. Then the nymph finds a mid-sized mammal (like a weasel or a rabbit) and feeds. Then it's back to the ground for the change to adulthood and a full-sized blood meal (a deer or human). Then they reproduce and die.
Damrow said ticks emerge on cool, muggy days, looking for their final host. "They'll feed for as long as it's humid," he said. "When it's dry, they go under the grass or leaves. Eventually, when things get too dry sometime in July, they're gone for the year."
Until then, Damrow suggested that Montanans make periodic - preventive - checks, as ticks crawl around a host for several hours before biting.
"There is ample opportunity for detection," he said. "Look behind the ears, along the hairline and in body folds. They're looking for cool, dark, protected places to feed."
If you find a tick embedded in the skin, Damrow said it's best to use tweezers to remove it.
His instructions: "Grasp the tick near the point of attachment and pull upward firmly, but don't jerk or twist." If tweezers aren't available, use your fingers, but protect them - at least with tissue paper.
Apply antiseptic and a bandage to the site, then wash your hands with soap and water. Remember, ticks (and their fluids) carry diseases you don't want to get.