美国国家公共电台 NPR Beyond Lyme: New Tick-Borne Diseases On The Rise In U.S.（在线收听）

LAKSHMI SINGH, HOST:

Ticks are known to carry Lyme disease. You probably already know that. But there are about a dozen other diseases carried by ticks that are cropping up and spreading across this country. It's part of a trend around the world. Over the past month, NPR has been reporting on why this is happening. NPR's Michaeleen Doucleff looks at the surge of new diseases caused by ticks and new ideas to stop them.

MICHAELEEN DOUCLEFF, BYLINE: It all started in the shower. Tucker Lane had just spent the day outside. He's a plumber. He got undressed, looked down and there they were.

TUCKER LANE: Two ticks on my right hip directly next to each other.

DOUCLEFF: Tucker grew up on Cape Cod. Ticks are everywhere in the summer, so he brushed it off.

LANE: I didn't really think much of it because I've been getting tick bites my whole life so no big deal.

DOUCLEFF: A few months later, that all changed. Tucker had just turned 21, and he got a pounding headache.

LANE: Two hours later, I was sweating, cold, had, like, tremors and the headache was even worse.

DOUCLEFF: He started projectile vomiting, had a fever, double vision. Tucker's mom, Lynn Cash, was so worried, she rushed him to the hospital.

LYNN CASH: Immediately he got worse.

DOUCLEFF: Scans of Tucker's brain showed that it was swelling, and he was losing consciousness. So they sent him to Brigham and Women's Hospital in Boston.

CASH: By the time they got him upstairs within another 48 hours, he was in a coma.

DOUCLEFF: And barely breathing.

CASH: He was on full life support. If you opened his eyelids, he was gone. I mean, I've never been so devastated in my whole life.

DOUCLEFF: The doctors knew something was attacking Tucker's brain, but they had no idea what it was. Lynn thought she knew where the problem was coming from.

CASH: I knew it was a tick thing. I knew it was a tick thing.

DOUCLEFF: Lynn's family has been on Cape Cod for many generations. She's seen a lot of Lyme disease, but nothing like this. This was something new, something frightening. And she was right. It was coming from the ticks. Across the country, this is happening more and more. People are catching new diseases from ticks. Felicia Keesing is an ecologist at Bard College. She says over the past 50 years, scientists have found at least 12 new ones, and old diseases are spreading.

FELICIA KEESING: There's a disease called anaplasmosis, babesiosis. There's Rocky Mountain spotted fever.

DOUCLEFF: And that's just in the Northeast. In the Midwest, there's Heartland virus and Bourbon virus, which can be deadly. Across the South, you've got ehrlichiosis. And out West, there's a new type of spotted fever.

KEESING: The more we look, the more we find.

DOUCLEFF: Most of these diseases are still rare, but there's one that really worries Keesing and her collaborator, her husband Rick Ostfeld.

RICK OSTFELD: Our local ticks - this black-legged tick - occasionally and fairly rarely carry a deadly virus. It's called Powassan virus.

DOUCLEFF: Powassan - it's named after a town in Ontario, Canada, where it was discovered. Now the virus is here in the U.S. What makes Powassan so dangerous is it attacks the brain, makes it swell and can kill you, which brings us back to Tucker's case in Boston. Doctors didn't realize it at the time, but it was Powassan flooding his brain, had him fighting for his life.

JENNIFER LYONS: His MRI was particularly severe.

DOUCLEFF: That's Tucker's neurologist Jennifer Lyons. She thought the virus was causing irreversible damage. Tucker's mom, Lynn, says the doctors told her there really wasn't anything else they could do.

CASH: I did a lot of praying. I'll tell you that much.

DOUCLEFF: Then one morning after he had been in a coma for about a week, Lynn went to visit Tucker. She opened the door, and...

CASH: He turned his head.

DOUCLEFF: Looked at her and tried to speak.

CASH: The only thing that he - that came out of him was a (sighing) because he recognized me.

DOUCLEFF: That was the turning point. From then on, Tucker started to get better fast. He started to breathe on his own, to recognize people. In two weeks, he was out of the hospital. Tucker says he was never scared or worried because he was always surrounded by his family.

LANE: I woke up, and they were all there - my cousins. They were just joking with me and making me laugh and stuff like that. So it was all good.

DOUCLEFF: And it was all good. Tucker recovered. His doctors say it was remarkable. It might be because he's so young and healthy. His body was better able to fight the infection, but not everyone is as lucky. Ostfeld says when you catch Powassan...

OSTFELD: You have about a 15 percent chance of dying, and if you survive, about a 50 percent chance of being permanently disabled.

DOUCLEFF: So is there a treatment or cure for Powassan?

OSTFELD: There is no treatment and no cure.

DOUCLEFF: So the best thing to do is to avoid getting it in the first place. And he and Keesing think they've come up with something that may help, a contraption that may reduce the cases of Powassan, Lyme and other diseases. To show me, Ostfeld takes me to the woods near his lab in the Hudson River Valley.

OSTFELD: So it's a mix of forest trees out here, but it's dominated by the oaks.

DOUCLEFF: The floor is covered in a thick layer of leaves, sometimes one, two-feet deep. Hidden underneath the leaves are metal boxes.

OSTFELD: These are our traps.

DOUCLEFF: They're about the size of a wine bottle. Inside is Ostfeld's secret weapon.

OSTFELD: So I just reach into the bag. I can already feel that it's a pretty fat mouse.

DOUCLEFF: Aw. He's cute.

A little, white-footed mouse about the size of a dinner roll, dusty brown with a white belly. Over the past 25 years, Ostfeld has been trapping and studying these animals, and he's figured out something key. They're covered in ticks.

OSTFELD: I'm going to inspect for ticks.

DOUCLEFF: I see you're using tweezers to try to find the tiny, little ticks on him.

OSTFELD: I'm moving her ears around so I can see very well to see if there are any ticks.

DOUCLEFF: Some mice have 50, 60, 100 ticks on their faces and ears. Most of these ticks are carrying Lyme. Some may be carrying other scary diseases. So Ostfeld had this idea - use the mice to kill the ticks, turn the mice into little assassins running around the forest. It's surprisingly simple to do. Remember those boxes Ostfeld used to trap the mice? What if you put a chemical inside that kills the ticks on the mice? Kind of like a mouse carwash...

OSTFELD: That delivers a tiny bit of tick-killing chemical.

DOUCLEFF: So this is just the same stuff that everyone puts on their - like just a couple drops on the back of your cat or your dog?

OSTFELD: Yes. But it's an even tinier, much tinier drop. So a little bit goes a long way.

DOUCLEFF: And it lasts a long time. So after the mouse leaves the box, it kills ticks that land on it for weeks. This spring, Ostfeld and Keesing have launched a massive experiment. They're putting these tick boxes around 1,200 homes in upstate New York. Then they'll check to see if the boxes keep people from getting sick. If it works, it'll be a first.

KEESING: Because so far, there have been no success stories of treating people's individual properties.

DOUCLEFF: Because here's the thing, it's not enough for just one or two families in a neighborhood to protect their yards. Keesing says the whole community has to come together to fight the onslaught of tick-borne diseases. Michaeleen Doucleff, NPR News.