As if we all needed another health concern, Lyme disease season has arrived.
A walk in the woods might be an appealing way to relieve stress from the coronavirus lockdown, but it comes with an underappreciated risk: Ticks that carry Lyme and other illnesses.
Some of the basic symptoms of a Lyme infection — fever, malaise, fatigue — can resemble Covid-19. That’s a worry nobody needs. In addition, contracting a serious illness like Lyme could put you at greater risk from Covid.
“We already know people with underlying conditions are more vulnerable for complications with coronavirus,” said Shannon L. Delaney, a neuropsychiatrist and director of child and adolescent evaluation at Columbia University’s Lyme and Tick-Borne Diseases Research Center. “Certainly, people with tick-borne illness fall into that category.”
Fortunately, you don’t have to skip that walk in the forest. Understanding Lyme disease can help you to minimize your risk.
Where? Lyme disease is most prevalent on the Eastern Seaboard of the United States, from Virginia to Maine, and from the western reaches of New York and Pennsylvania to the East Coast and into Atlantic Canada. It’s also found in the Upper Midwest, primarily in Wisconsin and Minnesota. But its range is expanding. “Now it’s spreading into Michigan, Illinois, Iowa, and the southern part of Midwestern Canada as well,” said Richard S. Ostfeld, a disease ecologist and tick specialist at the Cary Institute of Ecosystem Studies.
Cases are also found in states outside these hot spots, including in California, Texas and Florida, but numbers there remain comparatively low.
Ticks like the woods. “They tend to be much more scarce on lawns, although they do exist,” Dr. Ostfeld said. Ticks tend to live in shady forests with leaf litter, and in the type of shrubby barberry or honeysuckle thickets that tend to cover the understory of woods near neighborhoods and roads.
“They are extremely abundant in small forest patches of a couple acres or less,” Dr. Ostfeld said. “Large expanses of continuous forest tend to harbor fewer ticks than little fragments of forests in suburbia or an agricultural landscape.” That’s because these patches tend to have higher concentrations of disease-carrying mice, because of a lack of predators. “Owls, foxes, bobcats, weasels, are doing us a favor,” Dr. Ostfeld said, but fragmented woods tend to have too few of them to keep mice populations in check.
Based on surveys of acorns, which provide food for mice, Dr. Ostfeld said he expected 2020 to be “an average or slightly below average year for ticks.” The acorn signal for next year, though, is very clear: “Last fall was a huge acorn year. So we would expect 2021 to be a really bad Lyme year.”
Dr. Ostfeld added that it’s something of a myth that deer are the main carriers of Lyme disease. The so-called “deer tick” was misnamed when it was first discovered, he said. “We learned it was only a northern population of the black-legged tick,” which attaches itself to at least 50 different species of mammals including mice and chipmunks, and is the species of tick that most commonly transmits disease to humans.
Deer can carry Lyme, but in reality, the main culprits in terms of disease transmission are white-footed mice. Newly hatched ticks attach to the mice and other small rodents, acquiring the bacteria from their first blood meal, and passing it on to other mammals, including humans, the following year.
When? Is it above 45 degrees Fahrenheit, or roughly 7 Celsius? If so, ticks will be out. Climate change, by the way, is making the onset of Lyme season earlier each year, and making the season last longer.
What to wear? Basically, long sleeves and long pants. Dr. Delaney recommends tucking your pants into your socks so ticks can’t crawl up your legs. Wearing light colored clothing is a good idea, so dark ticks show up easily.
She also recommends you spray your clothes, shoes, and socks with the insecticide permethrin, which kills ticks on contact.
Permethrin shouldn’t be sprayed on skin. Instead, treat exposed skin with DEET or a chemical called IR3535, which she says is more commonly used in Europe, and has an excellent safety record. If you are taking bags out for outdoor sports, like tennis, spray your bags too.
Where to hike? Stay on the path. Stepping off the trail puts you directly into the leaves and brushy area that ticks love. “That’s where ticks hang out. You’ll increase your risk of tick bites,” says Brian A. Fallon, a psychiatrist and the director of the Lyme and Tick-Borne Diseases Research Center at Columbia University.
When you get home: Inspect your clothes and body for ticks. If you find one on your skin, remove it immediately and consult your doctor. She might put you on prophylactic antibiotics to prevent a Lyme infection.
Quick removal is important. The bacteria that causes Lyme disease, by far the most common tick-borne illness in North America, is believed to transmit after the tick has been attached for at least 24 hours (though other tick-borne diseases can transmit much faster). The Centers for Disease Control and Prevention has instructions for removing ticks.
You should save the tick, because you can (and should) send it to a commercial lab for analysis. It’s helpful to understand which, if any, of the many tick-borne illnesses you were exposed to if you develop symptoms later. In Connecticut, the state runs a lab that will analyze your tick free of charge.
Giving your clothes a spin in the dryer after that hike is a good idea, too, even if you don’t spot any ticks. A bit more than 10 minutes should be enough to kill any unnoticed hangers-on.
Lyme symptoms can show up any time between two days and three weeks after a bite. Fever, fatigue and malaise are hallmark Lyme symptoms, and are also among the symptoms of a coronavirus infection. “But the one major difference is presentation of respiratory symptoms,” Dr. Delaney said. That means if you’re coughing, it’s probably not Lyme.
It’s crucial to tell your doctor about any recent hikes or outdoor activity. The sooner you get treated for tick-borne illness, the better the outcome tends to be.
“If we’re changing our behaviors in terms of outdoor exposure, we need to think about this,” Dr. Delaney said. “Make sure you bring that up with your doctor. These tick-borne illnesses should be on your radar.”