fb-pixelTicks: They’re not just for hikers anymore - The Boston Globe Skip to main content
Globe Magazine

Ticks: They’re not just for hikers anymore

The menacing mites have invaded suburban backyards and even parts of Boston. And Lyme disease isn’t the only thing they carry.

Ticks don’t get diseases from deer, but they do get rides. The deer population inside Interstate 495 has quintupled since 1985.Essdras M Suarez/Globe File

Fae Healy awoke at 3 in the morning and immediately knew something was wrong — her husband, Patrick, a sound sleeper, was not in bed. Nor did he turn out to be in their Hudson home. It was raining, but on a whim she looked through the kitchen window and saw him lying on the front lawn.

“I remember falling off the front porch,” says Patrick Healy, who also recalls staying on the lawn in the rain because it cooled him off. Fae remembers his nonsensical answers to her questions. She drove him to a local hospital, where doctors found he had a high fever brought on by anaplasmosis, a potentially life-threatening illness carried by blacklegged ticks. Healy, who often found ticks on his body after mowing his lawn, spent 16 days in a coma as the disease attacked his system. Low blood pressure is a significant symptom, and Healy’s dropped to a level that caused kidney damage and put him on continuous dialysis. He spent a month in intensive care; when he was finally released, his doctors declared the then-61-year-old permanently disabled from the kidney damage. Healy, who’d had a long career as a nutritionist, found himself unable to work. That was in 2016, and he has since been able to stop dialysis, though he suffers from memory problems and lacks the stamina to mow his lawn. “But you know,” he says, “I’m doing the best I can.”


New England has long been a haven for blacklegged ticks — Lyme disease is, after all, named for Lyme, Connecticut. Exploding tick populations have led to a jump in instances of Lyme — about 6,700 cases were reported in Massachusetts in 2018, 10 times the number in 1999. We’re also seeing once-rare tick-borne illnesses become more common. A decade ago, some 50 Massachusetts residents were diagnosed with anaplasmosis, the disease that ravaged Healy; last year, it was about 700. Doctors are also seeing incidents of borrelia miyamotoi, a variant of Lyme that the standard tests for the disease don’t reveal, and even of the Powassan virus, which causes a rare and incurable disease that’s fatal for 10 percent of those who contract it.

Tick-borne diseases can be difficult to diagnose, generating both false negatives and false positives on tests. That has public officials saying the rise in lesser-known pathogens presents a growing public health concern. A case in point: Daniel Lennon, then of West Greenwich, Rhode Island, spent two years seeing specialist after specialist — 20 in total — for severe flu-like symptoms that started in 2013, when he was 23. Lennon found it hard to get out of bed and go to work. Some of the doctors speculated that he had multiple sclerosis, others said his problems were psychosomatic, and one diagnosed him with chronic fatigue syndrome.


Thomas Mather, head of the University of Rhode Island’s TickEncounter Resource Center, holds an adult tick in a pair of tweezers. Beau Jones

As his symptoms worsened, he had to quit his job as a video producer. He was still young enough to have health insurance through his parents, and he kept seeing specialists, one of whom ran a single-photon emission computed tomography test, or SPECT test, which measures blood flow to the brain. Lennon’s rate of flow was low, a symptom consistent with Lyme disease. But he hadn’t had Lyme’s tell-tale bull’s-eye rash (it’s estimated that up to 30 percent of Lyme infections have no rash), and had tested negative for the full panel of tick-borne illnesses. He doesn’t remember finding a tick on his body, either, but nymphal ticks are poppy-seed sized and easy to miss. About 20 percent of blacklegged tick nymphs carry Lyme, with between 5 and 15 percent harboring other diseases. After the SPECT results, however, he was tested again and got a positive result for babesiosis, a malaria-like tick-borne parasitic disease that causes red blood cells to burst.


Lennon’s insurer deemed the new test results dubious and refused to cover treatment. Desperate, he went to Massachusetts General Hospital to get his diagnosis confirmed. He says doctors there also thought the results were off because such high infection levels should have incapacitated him. They agreed to test him again anyway.

The next day they told Lennon to return for treatment — he had extremely high levels of the babesia parasite. Since then he has improved with medication and is living in Newton and working part time, despite lasting symptoms of extreme fatigue and joint pain. He estimates he’s spent $60,000 on treatment over the last four years, aided by his family and a LymeLight Foundation grant.

Lennon’s case highlights a gap in the public health system, says Dr. David Crandell, who co-directs the Dean Center for Tick Borne Illness at Boston’s Spaulding Rehabilitation Hospital. He says many primary care providers don’t question negative test results for Lyme and other pathogens carried by ticks. “You have to treat the symptoms, not the tests,” says Crandell. Meanwhile, the Massachusetts Department of Public Health says official Lyme numbers may represent only a tenth of actual cases. Undercounting comes from an arduous reporting process and other reasons, says Dr. Jeffrey Gelfand, an infectious disease specialist at MGH. Gelfand says DPH’s estimate is probably correct, and the same holds true for other tick-borne illnesses. Gelfand, who was not involved in Lennon’s care, does not believe he could have had babesiosis for two years. Crandell says such incidents do happen.


At the root of the increase in these illnesses is the massive spread of blacklegged ticks. Tufts University epidemiologist Sam Telford says he used to have to go to the Cape or the Islands to find ticks for his research, but now he can collect plenty of specimens in the Boston area. Multiple factors affect tick populations, but Telford and others note the boom of deer, the primary host — and mode of transportation— for adult ticks. Suburban landscapes, predator-free and with lots of low-hanging greenery, turn out to be a perfect habitat for deer, and their population inside the Interstate 495 loop has quintupled since 1985, to 50,000.

To be clear, deer are the main food source for adult ticks, but do not transmit disease to them — ticks get infected when as larva they feed on small mammals, primarily field mice and chipmunks.

Ticks are now so commonplace that we are most likely to encounter them in our own neighborhoods, according to multiple studies. Diana DiMascio, who was diagnosed with Lyme in 2015, jokes that the closest she ever gets to the great outdoors is looking at the grass from her back deck in Tewksbury. Telford says hikers and campers are probably safer than the rest of us because they are likely to wear repellant and perform daily tick checks. Around our own homes, most of us don’t take such precautions. People with pets may not protect them, either, creating another path for ticks to infect humans.


Another tick researcher, Thomas Mather of the University of Rhode Island, says his son recently showed him security camera footage of a deer in his backyard in Medford. “That’s shocking,” says Mather, because the deer would have had to travel about a half-mile on city streets to get to his son’s house. But then Mather has found ticks in some Boston parks, which wouldn’t have been the case even a few years ago. Ticks, he says, are “not just in the woods, not just at the summer camp, but in peri-urban settings. That’s where the real crux of the Lyme disease explosion is coming from.”

Deer also play host to lone star ticks, named for the white mark on females’ backs. Telford says numbers of those are also rising sharply in Massachusetts, which is why we are seeing more cases of ehrlichiosis, a disease similar to Lyme that’s carried by lone star ticks. Telford expects an increase in another lone star-borne disease, tularemia, which attacks the skin, lungs, lymph nodes, and eyes.

White-footed field mice are a primary infection source for larval ticks. Michael Hill/Associated Press/Associated Press

Our options for fighting back against the ticks in our backyards are limited. We aren’t likely to stop landscaping or declare open season on suburban deer. Spraying kills ticks, but also their chief predators, spiders. The one vaccine against Lyme was pulled from the market years ago, and while others are in development, they are far from ready.

Since ticks pick up diseases not from deer but from their juvenile food source, white-footed field mice, MIT biochemist Kevin Esvelt is working on a way to genetically modify mice to render them and their offspring immune to Lyme. Residents of Nantucket and Martha’s Vineyard, contained environments with plenty of ticks, are talking with Esvelt about creating a community-approved plan to release 50,000 to 100,000 of his Lyme-fighting field mice. The experiment is likely years off, though.

To fight other tick-borne infections, Esvelt thinks he can edit mouse DNA to fortify them with an anti-tick cocktail. If a tick bites such a mouse, it would get “a mouthful of nasty immune response,” he says. “It would detach and fall off and probably die.”

In the meantime, our best ally may be the insecticide permethrin. Studies by Mather and other researchers have found that ticks die within minutes of walking across garments treated with the chemical. It remains effective through multiple washes, although it should not be sprayed on the skin, which is best protected with DEET or lemon eucalyptus-based repellants. Cat owners should take special care with permethrin, which is toxic for felines. The EPA has classified it as a likely carcinogen if ingested but says it is safe when used as directed.

Mather, who receives some support from a permethrin clothing maker, worked on a 2018 trial of such clothes that found the chemical doesn’t appear to go from clothing into the human bloodstream. He’s currently conducting a five-year, $2 million study to test its effectiveness on New England outdoor workers. The military gives permethrin-treated clothing to Army soldiers and Marines, so Mather gets perplexed by people like the woman he spoke with a few weeks ago who never wears her permethrin-treated socks because she is “saving them for hiking trips.” If ticks are in your neighborhood, and increasingly they are, “why not wear [treated clothing]?” he asks.

After all, contracting Lyme and other tick-borne illnesses can be life-altering, as Tewksbury’s DiMascio found. She now checks herself, and her dog, for ticks after every trip outside.

Tom Gerencer is a writer and Maine native now based in West Virginia. Send comments to magazine@globe.com. Get the best of the magazine’s award-winning stories and features right in your e-mail inbox every Sunday. Sign up here.