Wednesday, May 1, 2019

Tick-Borne Diseases Are On The Rise

tick life cycleEighteen years ago, when I moved back to New Hampshire, I rarely came across ticks. The dog didn’t carry them unwittingly into the house, and I could spend the day in the garden or on wooded trails and not see a single, hard-shelled, eight-legged, blood-sucking creepy-crawly.

Not so anymore. Now, from the time of snowmelt in the spring to the first crisp snowfall of autumn – and often beyond – we find ticks everywhere: on the dog, crawling up the front door, along kids’ hairlines, on backs or arms or legs, and occasionally (and alarmingly) walking along a couch cushion or bed pillow.

With the increase in tick numbers has come an upsurge in tick-borne diseases. Lyme disease is still the most well-known and most common. But now we can add Anaplasmosis, Babesiosis, Borrelia miyamotoi disease, Ehrlichiosis, and Powasson virus to the list of tick worries.

Vermont and New Hampshire are home to more than a dozen species of ticks. In almost all cases, however, the blacklegged tick (Ixodes scapularis) – also known as the deer tick – is the one transmitting tick-borne diseases to humans.

“The blacklegged tick is kind of the bad guy,” said Patti Casey, environmental surveillance program director for the Vermont Agency of Agriculture. She noted that while some types of ticks feed almost exclusively on one or a few specific animal species, the blacklegged tick “tends to have a very broad menu.”

That menu of hosts includes rodents – white-footed mice are a favorite – and other small mammals during the larval stage, and larger ones, ranging from deer to dogs to humans, during the nymph and adult stages. It’s that first host – the small mammals – that typically share the pathogens that cause tick-borne diseases in humans.

The most common tick-borne disease in our region, after Lyme, is Anaplasmosis, whose symptoms include fever, chills, headache, muscle pain, confusion, and general malaise. Fewer than three cases were reported annually in Vermont from 2008 to 2010, but more than 200 human cases of Anaplasmosis were reported in 2016. Similarly, cases of Anaplasmosis in New Hampshire rose from 88 in 2013 to 317 in 2017.

Babesiosis has also been on the rise in the region, with 76 cases reported in New Hampshire in 2017 (up from 22 four years earlier). In Vermont, fewer than 40 cases have been reported, but the numbers are climbing. Babesiosis symptoms are similar to those of Anaplasmosis and of Lyme disease.

Those symptoms of general malaise – fever, aches, chills, and fatigue – are also common in Borrelia miyamotoi, another infection transmitted by black-legged ticks, and of the tick-borne disease Ehrlichiosis, which is transmitted by the lone star tick (so named because of a distinctive light-colored circle on its back, not because of any relation to the Lone Star State of Texas). This tick is beginning to appear in northeastern states.

While still quite rare – with only one human case reported in New Hampshire in 2017 and none yet in Vermont or New York – Powassan virus is causing concern for tick watchers. Although it hasn’t spread yet to people in large numbers, 40 percent of the deer harvested last year in New York showed signs of exposure to Powassan virus. With the same general symptoms of other tick-borne diseases, this virus can affect the central nervous system and cause meningitis and encephalitis.

How quickly ticks transmit diseases varies and is difficult to study effectively. As Alan Eaton, a retired University of New Hampshire professor and UNH Extension entomology specialist notes, “Nobody wants to volunteer to see how long it takes to have a disease transmitted to them.”

In experimental lab testing using rodents, it takes Lyme disease between 48 and 72 hours to be transmitted. But scientists have documented transmission of Borrelia miyamotoi disease and Anaplasmosis within the first 24 hours of attachment. Most terrifying is one study that showed Powassan virus being transmitted within 15 minutes of tick attachment.

While there are various reasons why ticks are becoming more abundant, climate change is a likely contributing factor.

Patti Casey said that longer shoulder seasons in April and October, when temperatures are not as reliably cold as they once were, give ticks a longer chance to mate and find a blood meal. Lee Ann Sporn, a biology professor at Paul Smith’s College in the Adirondacks, adds that one result of warmer, wetter weather trends has been that tick-borne diseases are an “almost year-round risk.”

Alan Eaton points to another factor in the spread of ticks and the diseases they carry: a changing landscape. “We’ve changed what had been a solid patch of woods decades ago to a situation where we’ve got little openings,” he said, referring to what conservationists call “forest fragmentation.” Eton noted that when people build houses in the woods, they make good mouse habitat in the process. With the mice come the ticks – and the diseases they transmit.

The most effective way to prevent tick-borne disease is to not get bitten. Experts suggest tucking shirts into pants and pant legs into socks when outside, treating clothes with a product that contains permethrin, wearing a repellent containing DEET, and performing daily tick checks, especially during the highest risk periods – from late spring through summer.

“You control a large amount of the risk,” Eaton said. “You decide what you do, what you wear, whether you use repellents, whether you check yourself for ticks. We live in a beautiful state with wonderful things to do. Understand the risks, continue to protect yourself. But continue to get out and enjoy this wonderful place, too.”

Meghan McCarthy McPhaul is an author and freelance writer based in Franconia, New Hampshire. The illustration for this column was drawn by Adelaide Tyrol. The Outside Story is assigned and edited by Northern Woodlands magazine and sponsored by the Wellborn Ecology Fund of New Hampshire Charitable Foundation.

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The Adirondack Almanack publishes occasional guest essays from Adirondack residents, visitors, and those with a biding interest in the Adirondack Park.

Submissions should be directed to Almanack editor John Warren at adkalmanack@gmail.com.




7 Responses

  1. Boreas says:

    Just pulled off a deer tick yesterday – first of the year.

    • gbear says:

      Wife & son had more than a dozen on them this past weekend. Last year I had 6 on me in one day, I did get Lyme disease. Nasty creatures to be sure. We live in eastern Essex County NY.

  2. Suzanne says:

    Love those deer ticks. I’ve long felt that I’ve had Lyme for years, starting from summers in the Hamptons and Adirondacks, where I spent a lot of time out in the woods. I was really sick for a year, aches, pains, muscle spasms, weakness — I had it all. I went to the hospital, St. Vincent’s in NewYork (now closed) but they could find nothing wrong with me, and suggested that they had an excellent mental health facility because obviously I was nuts or making it up. I continue to have arthritis and the very annoying muscle spasms in my back and neck. I asked my doctors at Elmhurst Hospital in Queens to do the test for Lyme, and at first they refused, saying it was just osteoarthritis, although X-rays showed no such thing. The Lyme test came back negative, but it is a very minimal test at best, and further testing is expensive. So many doctors believe that it is just a fiction of one’s lost mind and refuse to believe that it’s real. So, good luck with that. I’ll just take another ibrophen, although that does nothing. My suggestion: drink heavily. You’ll still hurt, but you won’t care.

  3. Charlie S says:

    “Vermont and New Hampshire are home to more than a dozen species of ticks.”

    There are still some places where ticks have not yet set roots! I was up near Lincoln, Vt. last July where I stepped into a big field with waist-high grass and flowers to get to an old small cemetery. Walked into that thicket a hundred feet in, a hundred feet out….and not one tick appeared on my person. At Orwell, Vt. I stepped into a farm field chest high hundreds of feet in, hundreds of feet…and not one tick. That was eight years ago and things could have changed since then, but even then I thought that was interesting that there were no ticks. In the woods across from Hope Cemetery in Barre, Vt…..loaded with ticks. The thicket of trees up from the Halpin Covered Bridge near Middlebury, Vt….loaded with ticks…… Benson, Vt….lots of ticks near the Town Hall………………………..
    Yet there are still some places to go and walk chest high in fields and no ticks. How much longer will this be?

  4. Scott says:

    There are ways to cut down on ticks, tick tubes full of permethrin cotton balls around the yard work well, mice use the cotton to make nests and at the same time are self eradicating ticks, Staten island, Cuomo has begun using deer feeders that have rollers that are treated with permethrin also, and it’s working, makes you wonder why they are not being deployed up north as well.

  5. ppm says:

    Yes , very frustrating trying to get the medical field to test especially if you have had a previous test come back negitive . Had one several years ago negitive . Developed many symptoms over past 4 to 5 years physicians very reluctant to retest . This month hospital thought I had Lupus I asked about Lyme as similar symptoms as Lupus disease . Lyme came back positive angry that damage maybe permant because of their reluctance to listen to my concerns way back. Also I have followed all preventive measures at least the last 3 years since the North Country professionals have made the public more aware of the increasing problem with tick . A little to late maybe Also be aware of other diseases tick may carry !!

    • Boreas says:

      ppm,

      FWIW, 3rd party insurance often dictates what physicians can test for depending on clinical findings and previous testing. In other words, your doctor often has to make a case to your insurance company so you don’t have to pay out of pocket. The tests are expensive, and many insurance companies are going to be reluctant to pay for them, especially when the tests aren’t very reliable to begin with. Therefore, doctors can be reluctant to order the tests. This process needs to change

      Unfortunately, once you are past the initial infection phase of the disease, the symptoms of late disease become very variable and non-specific, mimicking many auto-immune diseases, which are also difficult to nail down with lab tests. Insurance companies don’t like to pay for often unreliable repeat testing on any of these disease entities.

      It is a crappy situation, especially since it is an INFECTIOUS disease. Federal and state governments aren’t really taking the disease seriously. “Ticks aren’t in our region, why should we be concerned?” Well, your citizens travel to those regions for recreation and bring the disease home to burden that state’s insurance providers. So it IS a problem everywhere, regardless of the distribution of the disease vectors. As usual, it will likely take a celebrity with the disease shaming the governments into spending more money for research, containment, and treatment options. This may not happen until the blood-borne disease can be transmitted between humans.

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