Forbidding Forecast For Lyme Disease In The Northeast
March 6, 2017
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Stephen Reiss for NPR
Last summer Felicia Keesing returned from a long trip and found that her home in upstate New York had been subjected to an invasion.
Mice and ticks get along swimmingly. Other animals, such as possums, groom away ticks — and sometimes kill them. But white-footed mice tolerate ticks covering their faces and ears. Blacklegged ticks, like the adult female on the right, are tiny — about the size of a sesame seed
2015 reported cases
Stephen Reiss for NPR
Last summer Felicia Keesing returned from a long trip and found that her home in upstate New York had been subjected to an invasion.
"There was evidence of mice everywhere.
They had completely taken over," says Keesing,
an ecologist at Bard College.
It was a plague of mice. And it had landed right
in Keesing's kitchen.
"Not only were there mouse droppings on our
countertops, but we also found dead mice on
the kitchen floor," says Keesing's husband,
Rick Ostfeld, an ecologist at the Cary
Institute of Ecosystem Studies in Millbrook, N.Y.
The Hudson River Valley experienced a mouse
plague during the summer of 2016. The critters
were everywhere. For most people, it was just
a nuisance. But for Keesing and Ostfeld, the
mouse plague signaled something foreboding.
"We're anticipating 2017 to be a particularly
risky year for Lyme," Ostfeld says.
Keesing and Ostfeld, who have studied Lyme
for more than 20 years, have come up with
an early warning system for the disease. They
can predict how many cases there will be a
year in advance by looking at one key
measurement: Count the mice the year before.
The number of critters scampering around
the forest in the summer correlates to the
Lyme cases the following summer, they've
The explanation is simple: Mice are highly
efficient transmitters of Lyme. They infect
up to 95 percent of ticks that feed on them.
Mice are responsible for infecting the majority
of ticks carrying Lyme in the Northeast. And
ticks love mice. "An individual mouse might
have 50, 60, even 100 ticks covering its ears
and face," Ostfeld says.
So that mouse plague last year means there
is going to be a Lyme plague this year.
"Yep. I'm sorry to say that's the scenario
we're expecting," Ostfeld says.
Mice and ticks get along swimmingly. Other animals, such as possums, groom away ticks — and sometimes kill them. But white-footed mice tolerate ticks covering their faces and ears. Blacklegged ticks, like the adult female on the right, are tiny — about the size of a sesame seed
He's not exactly sure which parts of the Northeast
will be at highest risk.
But wherever Lyme exists, people should be vigilant,
says epidemiologist Kiersten Kugeler at the Centers
for Disease Control and Prevention.
"Whether it's a bad season or not, there's still going
to be a lot of human cases of tick-borne diseases,"
she says. "What's important for people to know is
that the ticks are spreading to new areas — and
tick-borne diseases are coming with them."
Back in the early '80s, the disease wasn't that big
a problem. Cases were confined to two small
regions: western Wisconsin and the area from
Connecticut to New Jersey
Since then, Lyme cases have shot up in number
and spread in all directions: "The only place
that they haven't really spread is into the
Great Lakes and the Atlantic Ocean, for
obvious reasons," says biologist Rebecca Eisen,
who's also at the CDC.
Now Lyme is present in more than 260 counties,
the CDC reported in 2015. The disease shows
up in Maine, swoops down the East Coast into
Washington, D.C., and southern Virginia.
Then it hops to the Midwest into northern
Indiana, Illinois, Wisconsin and Minnesota.
There are also small pockets of Lyme on the West Coast.
The number of confirmed and probable Lyme disease cases
in the U.S more than doubled from 2001 to 2015. In 2015,
95 percent of confirmed
cases were reported in the 14 states labeled below.
2001 reported cases2015 reported cases
"They also cut down trees for commercial use,"
Ostfeld says, "to make masts for ships, and for
firewood."
Since then a lot of the forest has come back —
but it's not the same forest as before, he says.
Today it's all broken up into little pieces, with
roads, farms and housing developments.
For mice, this has been great news.
"They tend to thrive in these degraded,
fragmented landscapes," Ostfeld says
, because their predators need big forests
to survive.
Without as many foxes, hawks and owls
to eat them, mice crank out babies.
And we end up with forests packed
with mice — mice that are chronically
infected with Lyme and covered with ticks.
So all these little patches of forest dotting
the Northeast have basically turned into
Lyme factories, spilling over with infected ticks.
Then people come along and do the darndest
thing, Keesing says: They build their dream
homes right next door. "So we see that
humans are putting themselves in these
areas where they're most at risk," she says.
Stephen Reiss for NPR
And that means people, in some areas, may be
putting themselves at risk for Lyme every single
day without even knowing it, says the CDC's
Kiersten Kugeler. "In the Northeast, most
people catch Lyme around their homes,"
she says. "People out gardening. People playing
in their backyard. Mowing the lawn."
So what can you do to keep from getting
infected? Add a tick check to your daily
routine, Kugeler says. When you're in the
shower check your body for tiny ticks,
especially the places they like to hide.
"That's the scalp, behind the ears, the
armpits and in the groin area," she says.
If you do find a tick, get it off as quickly as
possible. The longer an infected tick stays
on your skin, the greater the chance it will
pass the Lyme bacteria on to you. Generally,
it takes about 24 hours for the tick to infect
a person after it starts biting.
Then be on the lookout for Lyme symptoms —
like a red rash or a fever. It anything crops
up, go see a doctor immediately. Don't wait:
The earlier you get treated, the better
chance you'll have for a full recovery.
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CENTER FOR DISEASE CONTROL
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CENTER FOR DISEASE CONTROL
How to remove a tick
- Use fine-tipped tweezers to grasp the tick as close to the skin's surface as possible.
- Pull upward with steady, even pressure. Don't twist or jerk the tick; this can cause the mouth-parts to break off and remain in the skin. If this happens, remove the mouth-parts with tweezers. If you are unable to remove the mouth easily with clean tweezers, leave it alone and let the skin heal.
- After removing the tick, thoroughly clean the bite area and your hands with rubbing alcohol, an iodine scrub, or soap and water.
- Dispose of a live tick by submersing it in alcohol, placing it in a sealed bag/container, wrapping it tightly in tape, or flushing it down the toilet. Never crush a tick with your fingers.
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