Tick Check: Why Lyme Disease is on the Rise in Pennsylvania

September 25, 2015

Mary Beth Thakar is so passionate about getting the word out about Lyme disease, she wrote a song about it. Well, she re-wrote the lyrics to the tune “There Was An Old Lady Who Swallowed a Fly.”

The first verse goes like this: I know an old lady who was bit by a tick...or some kind of bug...maybe a tick. She might get sick.

Thakar’s singing about herself, but she’s only 58. She's sitting at the piano, inside her home in southwestern Pennsylvania—between Washington and Beaver County. It’s dark and cool. Pink and orange zinnias are blooming just outside the door, and there are late-summer raspberries and green beans to pick in the garden. But Thakar can’t make it out to enjoy the sunshine or climb the short slope up to the garden in her backyard.

“I have had to use my walker ever since February. I can’t go anywhere without a walker,” she says.

Her feet are numb. It’s just one of the many symptoms she has catalogued on a spreadsheet. She’s also lost 70 pounds, has experienced heart palpitations and has sore joints—a more classic symptom of Lyme disease. Thakar says she might have been bitten in her garden, but she can’t be sure.

“I had not seen a tick. I had not had a bullseye rash,” Thakar says. “All these things, I thought they were necessary before you could get Lyme disease.”

Thakar was just diagnosed with Lyme this year, but she thinks she might have become infected about five years ago.

She’s certainly not alone. Since 2011, Pennsylvania has reported the most cases of Lyme disease in the country. And it’s only going up. According to the Pennsylvania Department of Health, there were 6,000 cases in 2013. A year later, it jumped to 7,500 cases.

Earlier this year, the Department of Environmental Protection confirmed that there were black-legged ticks—which transmit the disease—in every county of the state.

Indiana University of Pennsylvania's Tom Simmons tracked down some of the ticks in that study himself. Simmons and his students have been studying ticks since 2001.

From his office window in Indiana County, you can see the hillside where the university’s tick study plots are located. By November, it will be covered in adult ticks as they molt from their nymph stage.

In his office, where there’s a cartoonish, inflatable tick hanging from the ceiling, Simmons pulls out vials of ticks he’s collected. He looks at ticks in three stages of development under a microscope—an adult, a nymph and a larva.

“You’ll see on all of these, the front legs are a little bit longer,” Simmons says.

The legs help them to latch onto unsuspecting hosts, and the ticks then feed on blood through their long, pointy mouths.

Adult ticks can give you Lyme disease, but it’s the nymph ticks that are the biggest concern. They’re as small as a poppy seed, so you might not even notice they’ve climbed up a pant leg and latched on. They suck your blood, and within four days, they drop off. You may be none the wiser.

Not every tick that carries Lyme bacteria will give its host the disease. Still, Simmons says the number of ticks with Lyme has grown—about half of the adult ticks collected in their statewide study tested positive for the bacteria. He says the reasons why are complex, and still a bit of a mystery.

Simmons says some genetic studies are providing insight into why ticks are being reported in places like western Pennsylvania for the first time.

“It’s not that the ticks are here, and the populations are increasing,” he says. “It’s that they are moving—they’re migrating."

One theory is that there used to be plenty of ticks in Pennsylvania. But when early settlers cleared the forests to make way for farmland, and hunted the deer to near extinction, the ticks retreated.

“And they survived in pockets along the East Coast, including Long Island, where I’m from,” Simmons says.

Now that forests have regenerated, and deer are plentiful again—giving ticks a host to mate on and a vehicle to get around on—ticks are moving back to their old stomping grounds.

Simmons says western Pennsylvania is the western edge of this new tick re-colonization—and the huge growth of Lyme disease.

But the incidences of Lyme disease in the southwestern part of the state have tripled, which has been a surprise.

“The original dogma was that they need mild conditions.” Simmons says. “But now as they’ve moved into areas like western Pennsylvania and higher elevations, that dogma’s changed.”

Ticks don’t die off in colder weather, and they don’t hibernate. They just become inactive.

In New York’s Hudson Valley, where ticks and Lyme disease have been studied for decades longer than in Pennsylvania, researchers are finding that climate change may also play a role in the spread of Lyme.

Ecologist Taal Levi of Oregon State University says warmer springs and summers, like the ones we’re experiencing and expecting to continue due to global warming, can cause tick feeding cycles to become more asynchronous in colder places like western Pennsylvania. That means the nymphs wake up from winter first, feed on small mammals like mice and chipmunks—and can pass Lyme bacteria to them.

“Then the larvae come out later, and everything they feed on, every mouse they feed on, has already been infected,” Levi says.

Those larvae become infected nymphs, and then the nymphs become a danger to humans and pets.

“So if you live Maine, or New Hampshire or even more inland systems like Pennsylvania that are colder, you might expect Lyme disease to get worse,” says Levi.

Levi is also interested in vertebrate communities and ticks—how the elimination of wolves and mountain lions in the Northeast removed the main predator for now abundant deer, which could be a factor in why there are so many ticks. There are also fewer foxes and small predators to control the small mammal populations which carry and spread Lyme bacteria.

Meanwhile back in Washington County, Mary Beth Thakar isn’t giving Lyme disease the upper hand. She’s already bought vegetable seeds for next growing season.

“I’m planning on being out there, planting my garden,” Thakar says.

But this time, she’ll be spraying her pants and socks with insecticide before she does. The Center for Disease Control recommends a number of precautions that people can take to protect themselves from being bitten by black-legged ticks, including trimming back tall grass or brush at the edges of lawns and gardens, and walking in the center of trails while hiking, to avoid tick hiding spots.

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This story is part of a collaboration with iSeeChange, a community climate and weather journal. iSeeChange provides a groundbreaking environmental reporting platform that combines citizen science, participatory public media and cutting-edge satellite and sensor monitoring of environmental conditions.