Tick expert cracks tough cases

Glen Scoles, entomologist, tick specialist
Entomologist Glen “Tick” Scoles. (Photos by Robert Hubner, WSU Photo Services)

The right way to remove a tick

 

CDC graphic
CDC graphic

Contrary to folklore, do NOT apply nail polish, petroleum jelly or a burned-out match to an attached tick, as its mouthpart can remain embedded in the skin. Instead:

  1. Using fine-tipped tweezers, grasp the tick as close to the skin’s surface as possible.
  2. Pull upward with steady, even pressure. Don’t twist or yank the tick out.
  3. After removing the tick, thoroughly clean the bite area.

PULLMAN, Wash. – As the green deepens and hikers take to the forests and fields of the Northwest, ticks are emerging for their first blood meal of the season. While most people cringe at that thought, a Washington State University scientist is enthralled by the eight-legged beasts. So much so that he once had 200 ticks crawling up his legs and, instead of running away, he did his research.

His boss calls him Glen “Tick” Scoles. He studies a parasite whose size from infancy until its last blood meal at two years can swell to the equivalent of a human baby morphing into a walrus.

Scoles is an entomologist with the U.S. Department of Agriculture’s Animal Disease Research Unit at WSU. He has spent 17 years studying a tiny life form that’s detested outside scientific circles.

“I’m a curious person and can be fascinated by almost anything. Ticks provide a never-ending supply of intriguing questions so focusing on them helps to keep me on task,” he said at his campus office where pictures of ticks far outnumber those of family members.

“Sometimes my kids roll their eyes when I talk about ticks at home,” he said. “Then I remind them that it’s the ticks that are paying our bills.”

The Lyme scare

Many people associate ticks with Lyme disease, a bacterial infection that can cause chronic illness and pain unless treated early with antibiotics. Each year, 20,000 to 30,000 confirmed cases are reported nationwide, according to the U.S. Centers for Disease Control and Prevention.

In 2011, 96 percent of those reports came from 13 states – not one of them farther west than Minnesota. Even so, many rational folks out West still view Lyme disease as a big summertime scare, said Scoles.

“It’s one of the first things people ask me when they find out what I do for a living, and I tell them that the chances of someone acquiring the disease in this area are very, very low,” he said.

“The Northeast and upper Midwest account for the majority of reported cases of Lyme disease,” he said. “Here in the Northwest, the western black-legged tick that transmits it is very rare, and only a tiny fraction carries the pathogen that causes Lyme.” (In Washington state, two confirmed cases were reported in 2011, according to the state’s department of health.)

Even if more ticks did carry Lyme, they need about two days to inject the corkscrew-shaped bacteria through a person’s skin and into the bloodstream. That gives people plenty of time to scan their bodies and remove the critters before they can release any harmful microbes, said Scoles.

Poisonous ingredients

A Rocky Mountain wood tick, a species found in Washington state, crawls on Scoles’ finger. They are rare but their saliva can carry organisms that cause Rocky Mountain spotted fever and paralysis.

Other serious tick-borne infections in the U.S. include Rocky Mountain spotted fever, relapsing fever and babesiosis, all characterized by flu-like symptoms but avoidable if the tick is removed soon enough.

Most bizarre is tick paralysis. Relatively rare, it’s caused by a neurotoxin in the saliva of certain tick species, including the dog tick and Rocky Mountain wood tick found in pockets of the Northwest. Powerful enough to bring down a human or a cow, the paralysis is gradual, often starting in the legs and moving upward, said Scoles.

For a terrified person or animal rendered immobile, the cure is amazingly simple: “Remove the tick and symptoms will start to dissipate,” he said.

Crawling tool kits

Fortunately, of the more than 700 tick species on the planet, only 86 are found in the U.S. – “or unfortunately, if you like ticks,” said Scoles.

Since he fits into the slim category of tick-likers, the obvious question is, Why? After all, these crafty creatures suck blood for days at a time and, depending on the species, can introduce an array of bacteria, viruses or parasites into people, pets and wildlife.

In part, it’s their remarkable gadgetry, explained Scoles. With hooks on their legs that hitch to fur, hair and cloth; mouthparts that act like scissor blades; and a serrated tube that alternately sucks blood out of the host and pumps its own saliva in, “they’re like perfect tiny machines, all flawlessly engineered by evolution,” he explained.

Cracking cases

While Lyme may be the most widely publicized of tick-borne diseases in the U.S., it’s far from the only one, said Scoles.

He should know. From New England to Texas to Kenya, Scoles has “made important historical findings in ticks and the associated diseases they transmit,” said USDA research unit leader Don Knowles who hired Scoles at WSU in 2000 and jokes about “Tick” being his middle name.

In fact, Google “Scoles” and “ticks” and you’ll find an impressive roster of published research articles he has co-authored or that cite his work. While doing postdoctoral work at Yale University, he discovered in Connecticut another illness-causing organism transmitted by the same black-legged deer tick that spreads Lyme disease.

Less than a decade later at WSU, he identified the cayenne tick as the main carrier of a mysterious and potentially deadly 2009 outbreak of piroplasmosis, or equine tick fever, among prize quarter horses in southern Texas.

“Prior to that outbreak, scientists knew of only two tick species capable of transmitting piroplasmosis. He discovered a third,” explained Knowles. The finding was later published in the journal Emerging Infectious Diseases. (See http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310643/)

Tick, tick, tick

Even the way a tick goes searching, or “questing” for a host is fascinating, said Scoles. As if biding its time, the creature perches on a grass blade, twig or leaf and waits for a potential meal ticket to come along.

CDC graphic

Tick life cycle

Most ticks go through four stages: The egg, six-legged larva, eight-legged nymph and adult. To survive, ticks must eat blood at each stage after they hatch. Most can’t find hosts and will die – good thing, too, since one tick can lay up to 5,000 eggs.

“It can’t visually see if or when that happens,” he said. Instead, it detects carbon dioxide from the host’s breath or a shift from light to dark as a shadow approaches, he explained.

Once the figure is close, the tick reaches out with those hooked legs, snags the host and then hunts for a warm patch of skin to drill. Popular dining spots on humans include: Under shirt collars, at the rim of a sock, behind the ears, on the scalp and at the nape of the neck, said Scoles.

Unlike the dine-and-dash mosquito, the tick settles in for a meal that unfolds over 5-7 days. If the host is lucky – as most are – the engorged tick will fall off and be gone with no lasting effects. But if the host is unlucky, “the tick will have delivered a pathogen into its bloodstream that triggers an infection,” said Scoles.

Druggists

Scoles points out that, when it comes to pharmacology, ticks appear to be savvy in ways that humans are not. Like portable mini-pharmacies, they pack an elaborate assortment of chemical agents in their saliva. By studying tick spit, scientists “hope to gain insights on ways to improve drugs to control clotting and inflammation,” he said.

First, ticks create a numbing agent that keeps hosts from feeling the bite and subsequent itching, along with chemicals to prevent the host’s immune system from responding. They even produce a cement-like substance that hardens around the mouthparts, “firmly attaching the tick to the host’s skin,” Scoles explained, bounding from his chair to scribble a diagram on his dry-erase board of a saw-toothed feeding tube encased by a cone of rubber cement.

Once firmly aboard, the tick injects an anticoagulant to keep the host’s blood flowing, Scoles said. “Without it, red blood cells would clot, disrupting a meal that’s critical to the tick’s survival.”

Field of dreams

Massaro Ueti is a research scientist who works in the same USDA unit as Scoles. In 2010, the two of them traveled to Kenya to study ticks that infect cattle. By foot, they approached a field packed with scuttling bloodsuckers.

“Glen’s face lit up,” recalled Ueti. “I mean, here we were in this place with giraffes and zebras – and all he wanted to do was see the ticks. And you talk about ticks; I’ve never seen so many in one place. They were everywhere.”

Carrying tiny capped jars, the scientists waded in. Detecting their presence, a swell of ticks rolled toward them, creeping up their shoes and pants in search of a patch of skin to power-drill. Hand-in-glove, Scoles calmly removed the living tool kits and inserted them into containers.

Ueti followed the same process but, “I don’t think I enjoyed it as much as Glen did,” he said.

“It’s funny how most people go out of their way to avoid ticks,” Ueti continued. “But Glen? He goes out of his way to find them.”