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A tick by any other name
Infamous Lyme disease-spreading deer tick misnamed

By Robert Miller
THE NEWS-TIMES
2003-05-01

It's the same old, blood-sucking, mammal biting, disease-spreading parasite
we've all come to know and loathe.

It's just not a deer tick.

As Lyme disease season starts to kick in there's a different name for the
tick that spreads the disease.

It's not the deer tick. It's the black-legged tick.

"That's the technically correct common name," said Kirby Stafford, an
entomologist at the Connecticut Agricultural Experiment Station in New
Haven, who spends a good part of his year studying ticks and trying to
devise ways to keep them off humans.

The work is needed. Dr. Matthew Cartter, coordinator of the state Department
of Public Health's epidemiology program, said Tuesday Connecticut had the
highest per capita rate of reported Lyme disease cases in the United States
in 2002 - a dubious distinction Cartter said the state has held for
something like 25 years.

"It's here," Cartter said of Lyme disease. "It's in every county of the
state." State statistics show a considerable, albeit expected jump in
reported Lyme disease cases for 2002.

Stafford said the confusion over what tick was spreading Lyme came about
because entomologists made a mistake a few decades ago. They thought what
was commonly called a deer tick in Connecticut and the northeastern United
States was a species unto itself - Ioxodes dammini. "That's the name that's
stuck," he said.

But in 1993, entomologists at the Georgia Southern University - which houses
an institute of parasitology and is the Centers for Disease Control and
Prevention's tick repository - did a thorough study of the deer tick,
showing it wasn't a separate species at all. Instead, it was Ioxodes
scapularis - the black-legged tick - a species that's widespread throughout
the entire eastern United States.

Stafford acknowledged people will probably keep calling the tick a deer tick
because it feeds on birds, deer - and a lot of other mammals, including mice
and humans - during its two-year life cycle. But calling the same tick by
the same name avoids scientific confusion.

"In Wisconsin, they call the black-legged tick the bear tick,'' Stafford
said. "If you go to Kentucky, people will say 'Oh yeah, we have deer ticks.'
But they're talking about the lone star tick. (Amblyomma americanum)

Whatever its name, the black-legged tick has been extremely efficient at
spreading Borrelia burgdorferi, the bacterial spirochete that causes Lyme
disease. In Connecticut, it also carries two other diseases - babesiosis and
ehrlichiosis.

State Health Department statistics show that in 2002, there were 4,631
confirmed cases of Lyme disease in Connecticut. That's a big jump over the
3,597 cases reported in 2001.

It's also a continuation of a long-standing trend, due to the fluctuating
two-year life cycle of black-legged ticks. On odd-numbered years, the number
of Lyme disease cases reported to the state drops off. In the even years,
the number surges.

"I don't make much of the year-by-year statistics," Cartter said.

What is important is that over time, the numbers have gone steadily up. In
1991, there were 1,192 cases reported to the state; by 2002, that number had
increased four times over.

The numbers also show that Connecticut, with 136 cases of confirmed Lyme
disease per 100,000 people, has the highest rate of Lyme infection in the
United States.

Two of the four counties in the northern tier of the state were the worst
places to live in Connecticut, when it comes to Lyme. Windham County had 447
cases per 100,000 people; Litchfield County, 371 cases per 100,000. New
London County, with 247 cases per 100,000 people and Tolland County, with
243, were almost equally bad.

Fairfield County had 148 cases per 100,000 people in 2002. But because there
are a lot more people living in it than in the state's rural corners, it had
1,313 cases reported in total. That's nearly twice the 677 cases reported in
Litchfield County, which had the second-highest total.

"Fairfield County is amazing, when you think of all the homes there sitting
next to the woods," Cartter said. "It's that edge - where the backyard meets
the woods - where there are deer and ticks."

Cartter admitted the state numbers are deceptively low.

"For every reported case, there are probably 10 people who get treated for
Lyme disease by their family physician and those cases never get reported,"
he said.

When people get infected with the Lyme bacteria, they usually get flu-like
symptoms - a high fever, headache and aching joints - without a cough. They
often - but not always - get a tell-tale, 'bull's-eye' rash spreading from
the site of the tick bite. Of the 4,631 confirmed cases reported to the
state in 2002, about 2,700 had such a rash. And because the black-legged
tick in its nymphal stage is so tiny, it's easy to miss the embedded tick.

If people are treated promptly with antibiotics at the onset of the
infection, they usually recover without further medical problems. For those
who don't get that treatment - or even some who do - the latter stages of
the disease can include arthritic swelling of the joints, chronic and
debilitating fatigue, neurological disorders, heart problems, memory loss
and depression.

Because there is no way of medically stopping the spread of the disease -
the makers of a vaccine to block the disease pulled the vaccine off the
market in 2001 - Cartter said people must concentrate on prevention.

Of the six model programs in the United States that are trying to use a
combination of methods to keep ticks and people apart, three are in
Connecticut - in Torrington, Westport and Groton. These programs, funded by
the CDC, are trying to learn if a concerted effort - teaching homeowners to
edge their yards to keep ticks out, using chemical sprays to kill them - can
lower the rate of Lyme disease.

"It has to be done at a community level, to get people to do the things that
need to be done," Cartter said.


There will be a free, informational symposium on Lyme disease on May 10 from
9:30 a.m. to 12:30 p.m. at New Milford High School. For information, call
Karen Shaw at (860) 567-1193.


Contact Robert Miller

at

or at (203) 731-3345.