Maine recorded its worst year for Lyme disease in 2019, with 2,079 reported cases statewide. Experts in infectious disease weren’t surprised. And there’s no indication that the upward trend won’t continue this year.
Lyme disease is a serious illness caused by a bacterium that’s carried and transmitted by the deer tick. In Maine, it’s believed that about 40 percent of the deer ticks on the landscape carry this disease, based on testing conducted by the University of Maine Tick Lab. And deer ticks have been found in all of the state’s counties, though they are much more numerous along the coast and in the southern reaches of the state.
“Unfortunately, we’re just seeing more and more [Lyme disease] as ticks’ ranges expand and people are spending more time outside,” said Sara Robinson, infectious disease epidemiology program director for the Maine Center for Disease Control and Prevention. “There are a lot of factors that contribute to it.”
How to protect yourself from ticks
In recognition of May being Lyme Disease Awareness Month, the Maine CDC is actively spreading the word about how to prevent tick bites.
“We always focus on the same things: It’s always personal prevention,” Robinson said. “Wear your repellent. Treat clothing. Always remember to do a tick check, and don’t forget to do a tick check on your pets as well.”
Permethrin is one of the most effective chemicals for treating clothes and footwear so they become repellent to ticks, said Griffin Dill, tick expert with the University of Maine Cooperative Extension and the UMaine Tick Lab. In addition, repellents that include DEET and picaridin are effective in repelling ticks away from clothing and skin. And IR 3535 and oil of lemon eucalyptus also have proven effective, though for shorter periods of time, Dill said.
“Essential oil products are really popular for being natural products, but unfortunately, those products, the research that has been done — which is fairly minimal at this point — indicates if it works at all, it’s for really short periods of time,” Dill said.
[See where disease-carrying ticks are most common in Maine]
Avoiding tick habitat such as tall grass and dense underbrush is also key to avoiding tick bites. Ticks tend to prefer areas where they can seek shelter from the sun, since they tend to dry out easily. And they climb tall vegetation to “quest” for hosts. Perching at the end of a blade of grass or branch of a bush, they wave their front arms in the air to grab whatever animal passes by.
At home, you can take measures to reduce the tick habitat on your own property by keeping your lawn cut short and removing any leaf litter or debris. It’s also proven effective to create a gravel border around high traffic areas, such as a swing set or sitting area.
“There are also some steps you can take to reduce the number of ticks on your property,” she said. “Reduce deer habitat and create barriers between your lawn and the woods that will discourage ticks from traveling across.”
Why tick checks are so important
After spending time outside, it’s critical to conduct multiple tick checks, examining every part of your body by sight and touch to find ticks that may be attached.
Often, people can’t feel ticks when they bite and start to feed. The longer an infected deer tick is attached, the more likely it is to transmit Lyme disease. The amount of time it takes for a tick to transmit Lyme disease has long been debated, but Dill explained that no one length of time is correct.
The bacterium that causes Lyme disease resides in the gut of an infected tick. During the feeding process, as they consume blood, that bacterium becomes activated, replicates and moves throughout the tick’s body, Dill explained. It eventually makes its way to the tick’s salivary glands and is injected into the body of its host. Scientists have studied this process and have found that it usually takes 24 to 36 hours.
“I think some of the confusion stems from people focusing on the number and looking at it like it’s a light switch,” Dill said. “When in reality, it’s really more of a risk curve. Prior to 12 hours, the risk isn’t zero but it’s very low. Once you hit 24 hours, the risk really starts to go up. When you hit 36 to 48 hours, the risk is at its highest.”
[How to protect yourself from ticks in Maine]
Early symptoms of Lyme disease include a circular rash around the bite site (though not always) and flu-like symptoms including achiness, chills, fever, sweats, fatigue, malaise, headache, stiff neck, muscle soreness, joint pain, swollen lymph nodes and sore throat.
“June, July and August are the highest months of new [Lyme] symptom onsets,” Robinson said. “We want to make sure people think about it and remember it before those peak times.”
Scientists are still working to understand Lyme
Although most cases of Lyme disease can be cured with a 2- to 4-week course of oral antibiotics, patients can sometimes have symptoms of pain, fatigue or difficulty thinking that last for more than 6 months after they finish treatment, according to the Maine CDC. This condition has recently been coined post-treatment Lyme disease syndrome.
“I think it’s basically accepted at this point that a significant number — upwards of 15 to 20 percent — of people who are treated for Lyme disease do experience long-term complications,” Dill said. “The question lies in what is causing that. Is it an active infection that’s remaining? Is the bacteria somehow remaining in the body? Or is the initial infection triggering some sort of immune issue that causes the symptoms moving forward?”
[A Lyme disease vaccine for mice could help prevent human infections]
There is still a lot that isn’t known about Lyme disease and other tick-borne illnesses. Two diseases in particular — anaplasmosis and babesiosis — are also becoming more common in Maine. Both are carried by the deer tick and have early symptoms that are similar to Lyme.
In the scientific community, efforts are underway to combat these increasingly common diseases, especially Lyme.
“There are a number of companies working on [Lyme] vaccine trials,” Dill said. “Whether any of them make it to the market in the near term is anyone’s guess, unfortunately.”
For now, the best defense is to avoid being bitten by a tick in the first place. Be proactive. Avoid tick habitat. Wear protective clothing and repellent when you go outside. Conduct frequent tick checks. And if you are bitten and experience symptoms, call your health care provider.
Watch: How ticks crawl