May 13, 1996 in Nation/World

He Knows What Makes These Bugs Tick Spokane Microbiologist Tracks Disease Spread By Ticks

By The Spokesman-Review
 

Welcome to the Inland Northwest. Home of Bloomsday. Home of the floating golf green.

And home of Borellia hermsii - an unpleasant tick-borne menace that knocks people on their backs.

In a region rich with lakes, woods and - right now - spring vegetation, the area’s least-known miniscourge is thriving.

That scourge is a tiny bacterium lingering inside a tick known as Ornithodoros. One bite later, that bacterium leaves the tick and can produce relapsing fever - an illness that’s not fatal but can cause serious health risks.

The region from central Washington to Western Montana has the country’s highest concentration of ticks that cause relapsing fever.

Don Anderson, a microbiologist from Sacred Heart Medical Center, is one of those tracking that tick and researching why relapsing fever occurs here more than anywhere else.

This is the time of year Anderson gets busy. Doctors across the Inland Northwest send the hospital blood smears or test results, asking if a patient’s symptoms match those of relapsing fever.

Few cases of the fever have been reported since January, but they’re expected to increase over the next few months. The busiest time is June and July.

“One reason (for few reports) is the weather,” Anderson said.

“It hasn’t been warm enough for a lot of lake cabin visits.”

Tracking and collecting the tick is not a priority; it’s relatively abundant here and less common than other tick species such as the Dermacentor - or hard - ticks that can cause other problems like Colorado Fever.

The more urgent health issue is learning what happens once a person contracts relapsing fever.

The illness is so named because the microrganism transmitted by the tick keeps changing its chemistry after infection.

“Researchers have found that it can produce 24 different protein types” in the course of an ongoing infection, Anderson said.

Those infected come down with high fevers, chills and abdominal pain, then the symptoms disappear. After the body beats down the first onset, the bacterium - a spiral-shaped critter not unlike the agent causing syphillis - adapts and causes further flare-ups of symptoms.

“One guy apparently went through 13 relapses after one infection,” said Anderson.

Because it’s seemingly confined to the Northwest, relapsing fever hasn’t generated the same level of national concern as Lyme Disease and Rocky Mountain Spotted Fever, both caused by other ticks.

In Washington there were no confirmed cases of Rocky Mountain Spotted Fever and only four cases of Lyme Disease during 1995.

By contrast, doctors in Idaho and Washington last year dealt with at least 25 cases of relapsing fever, said Anderson.

The actual number of cases might be higher, because the illness often goes undiagnosed.

The tick that causes relapsing fever is a hit-andrun specialist. Other hard-shelled ticks tend to land on hikers or anglers, often staying embedded in the skin for weeks as a victim’s symptoms become obvious.

And unlike the outdoor ticks that most people worry about this time of year, the soft Ornithodoros stays indoors to pounce on prey for a 20-minute blood meal before returning to its nest.

Only the fever-causing bacterium is left behind.

The tick became well-known in 1968 when a group of Boy Scouts spent a night camping near Browne Mountain in Spokane.

Ten of those who stayed inside a cabin came down with relapsing fever, while only one of 22 who camped outdoors in tents contracted the disease.

The tick’s indoor preference is due to its natural host: mice or other rodents.

In the winter, those rodents come indoors and the ticks come inside with them.

“You can then get rid of the rodents, but the ticks can remain inside the nests for up to 15 years later,” said Anderson.

Those tracking the disease have varying theories on why it seems to be tied to this region.

“We just happen to have the right ecology and right habitat for this species of tick” and those conditions make us the unique site for relapsing fever, Anderson said.

Others, like Washington Department of Health scientist John Kobayashi, suggest the Ornithodoros tick and relapsing fever can be found in other parts of the country, but researchers have not discovered it yet.

“It’s like the E. coli variant we had that caused so much trouble three years ago. Now that people are looking for it, it’s found in many places,” he said.

Even though Anderson is seen by many as one of the region’s tick gurus, he won’t call himself an expert.

“I’m not a tick expert. I’ve never done any formal study (of them). I’ve just developed an interest in infectious diseases and how to best diagnose them. And that led me to pay closer attention to ticks,” he said.

Anderson’s microbiology lab has received a grant from Spokane Intercollegiate Research and Technology Institute to devise a better way of diagnosing relapsing fever.

Up to now, the one sure way to identify the disease is visual identification through a microscope.

But that method is imperfect, since the tell-tale organism can’t be found in the victim’s blood samples between flare-ups.

“Where it goes is not certain,” Anderson said.

“It goes into hiding we think, like the parasite that causes malaria. But where we don’t know.”

Chemical tests have proven less than perfect, since they give the same positive identification for several diseases.

The SIRTI project aims to develop a test that pinpoints only relapsing fever, said Anderson.

“That’s the key step, knowing what you’re dealing with,” he said.

“Because it takes about a week of antibiotics and that usually eliminates the infection.”

, DataTimes ILLUSTRATION: Color photo

MEMO: This sidebar appeared with the story: TICK TIPS The best way to avoid infections from ticks is to know where they live and how they behave. Ticks look for live hosts to grab onto. Some wait in grass, others in bushes or trees. Many grab onto their next meal and slowly work their mouth parts into the skin - especially areas near hair. Tick removal is a matter of debate. Some say the best method is using tweezers to pull out the head slowly. Others suggest scraping it out with something thin, such as a credit card. To avoid ticks in the first place, don’t walk barefoot. When hiking in thick vegetation, wear long-sleeved shirts. Wear light-colored clothes so that any ticks that do attach themselves are easier to see.

This sidebar appeared with the story: TICK TIPS The best way to avoid infections from ticks is to know where they live and how they behave. Ticks look for live hosts to grab onto. Some wait in grass, others in bushes or trees. Many grab onto their next meal and slowly work their mouth parts into the skin - especially areas near hair. Tick removal is a matter of debate. Some say the best method is using tweezers to pull out the head slowly. Others suggest scraping it out with something thin, such as a credit card. To avoid ticks in the first place, don’t walk barefoot. When hiking in thick vegetation, wear long-sleeved shirts. Wear light-colored clothes so that any ticks that do attach themselves are easier to see.


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