Tick season is upon us, and it’s shaping up to be a real doozy. Scientists predict 2017 will bear the highest number of ticks in recent years, with a jump in reported cases of tick-borne illnesses in some regions of the U.S.
Ticks are thriving thanks to a recent explosion of the white-footed mice population, which carry Lyme disease, Powassan virus and other tick-borne illnesses. Meanwhile, warmer winters caused by climate change are allowing ticks to remain active longer and carry diseases into new regions of the U.S.
Experts suggest people living in regions where these diseases are most prevalent ― the Northeast, mid-Atlantic and upper Midwest ― should learn about common tick misconceptions and best practices to avoid bites.
Black-legged ticks are the common carriers of several tick-borne illnesses, including Lyme disease, anaplasmosis, Powassan virus and babesiosis. They can have life cycles of up to two to three years and are most active between May and July.
Theodore G. Andreadis is the director of the Connecticut Agricultural Experiment Station in New Haven, which collects ticks and analyzes them for pathogens. He said his organization has received an unusually high number of samples this year and a “concerning” number have tested positive for disease-causing organisms.
“With the mild winter, we had ticks being brought into our lab for testing as early as February,” Andreadis said. “And the number we’re seeing in our laboratory are at least tenfold higher than we’ve seen in recent years.”
Andreadis said 38-40 percent of the ticks coming through his lab test positive for a type of bacteria that carries Lyme disease ― roughly 7-8 percent more than usual.
People who get Lyme disease suffer from unpleasant symptoms like a rash, facial paralysis and swollen knees. But it isn’t always easy to detect, and if left untreated can progress to complications like memory problems, heart rhythm irregularities and chronic arthritis.
“We’ve got a combination of a higher number of ticks and a higher prevalence of these infectious agents,” Andreadis said. “We really want the public to use some precautions. We got a lot of ticks out there ― that’s the bottom line. And we haven’t even reached peak season yet.”
So what’s behind the surge in white-footed mice and, in turn, ticks?
Dr. Richard Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies in Millbrook, New York, said acorns are likely to blame for the highest numbers of white-footed mice his organization has seen in 25 years.
Oak trees generally produce the most acorns every four to five years, a process known as masting. This occurred in summer 2015 and led to a spike in the white-footed mouse population, which relies on acorns as a key food source. These mice are the most common carriers of several tick-borne illnesses, such as Lyme disease and the Powassan virus, and also happen to be the primary hosts of black-legged ticks.
“As the climate warms, ticks are able to invade areas to the north that were formerly just too harsh, too cold, for them to persist.”
If baby ticks are able to latch on to mice during their larva stage, they have a much higher chance of both surviving their first year of life and becoming infected with a disease by the time they become nymphs, when they are most likely to transmit pathogens to humans.
While scientists are unable to generate a precise estimate of where in the country this phenomenon occurs, it seems likely it will be widespread throughout New England and the tri-state area, Ostfeld said.
“We saw huge numbers of acorns in 2015, mouse plagues in 2016 and an expected bad year for ticks and Lyme disease in 2017,” said Ostfeld.
According to the Centers for Disease Control and Prevention, roughly 95 percent of Lyme disease cases are reported in 14 states: Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia and Wisconsin.
But warmer winters caused by climate change are expanding the affected area and number of reported cases of tick-borne illnesses.
“As the climate warms, ticks are able to invade areas to the north that were formerly just too harsh, too cold, for them to persist,” Ostfeld said. “It’s really dramatic how much [Lyme disease] is spreading.”
Since the late 1990s, the number of reported cases of Lyme disease in the United States has tripled and the number of counties in the Northeastern and upper Midwestern United States that are considered high-risk for Lyme disease has increased by more than 300 percent, according to the CDC.
As Lyme disease cases increase, experts worry there could also be an uptick in other tick-borne illnesses, like the rare but dangerous Powassan virus. Infected humans have an estimated 10 percent chance of dying from the virus, and half of those who survive sustain permanent neurological damage.
Unlike Lyme disease, which can take ticks at least a day to transmit to hosts, Powassan pathogens are passed on in just 15 minutes ― making immediate removal and treatment essential.
“It’s a really nasty disease,” Ostfeld said. “It is not something you ever want to get. ... This is definitely a disease that public health officials and ecologists need to keep their eyes on.”
While reported cases of Powassan are still extremely rare, Ostfeld said its potentially debilitating effects are just another reason people should educate themselves about tick behavior, removal and prevention.
Common tick misconceptions
Here’s what people get wrong most often about ticks, according to experts, and why knowing the truth could be paramount to your health.
Myth: Ticks can jump or fly.
If you find a tick on your head or upper body, it’s most likely because you didn’t notice it crawl onto your lower extremities first. Feet and ankles are the entry point for most ticks, which is why Ostfeld recommends using tick-killing repellents on your socks and shoes.
Myth: Repellent with DEET is effective but toxic, so it should be avoided.
While some people are allergic to the chemical compound and should abstain from using it, studies suggest DEET isn’t actually harmful for most people.
The American Academy of Pediatrics recommends DEET can be used on children older than 2 months. Oil of lemon eucalyptus can be used on children over 3 years of age.
“Tickborne diseases can be serious and parents should not hesitate to use repellents on children,” said Dr. Christina Nelson, pediatrician in the CDC’s division of vector-borne diseases.
Myth: The winter kills off most ticks.
Ticks are able to bury deep into the soil or leaf clutter during frigid winter temperatures to avoid death. So while climate change is adding to the spread of ticks, there’s no scientific proof that warmer weather is preventing more ticks from dying during the winter.
Myth: Take your time detaching a tick. It’s better to coax it out than remove it quickly.
If you spot a tick on your body, you should remove it immediately. Grab the tick as close to the skin as possible with a pair of tweezers and pull it straight out.
“Time is of the essence,” Ostfeld said. “Don’t panic, but pull the thing out as quickly as you can. And don’t waste time using these folk remedies of Vaseline or nail polish or burnt match heads ― they don’t work.”
“The important thing is to get the tick out quickly,” he added. “If some of the mouth parts stay in the skin, it’s really not such a big deal.”
Myth: If you don’t have the red bull’s-eye rash, you won’t get Lyme disease.
Tick bites don’t always cause the telltale red bull’s-eye rash. If you’ve been outside and you feel any of these common Lyme disease symptoms, you should see a doctor.
Avoid areas with high grass, brush and leaf clutter.
Wear light-colored clothing, long sleeves and closed-toe shoes when hiking. Tuck your pants into your socks, too.
Don’t stray from the center of hiking trails.
Use repellent with permethrin to treat your clothes and shoes.
Use repellent that contains 20 percent or more DEET, picaridin, or IR3535 directly on skin for protection that lasts a few hours.
Thoroughly check your body if you’ve been in a tick-prone area, and shower as soon as possible once indoors.
Have a friend inspect hard-to-see areas of your body like the back, neck and scalp.
Parents should use bath time to thoroughly check young children for ticks daily.
If you find a tick, remove it with tweezers immediately.
Call your doctor if you experience any of these symptoms after removing a tick.
Throw your clothes in the dryer on high heat for at least 10 minutes to kill any stowaway ticks.
Check dogs and cats for ticks frequently, and ask your veterinarian about tick preventives for pets.
Bottom line: If you spend time outdoors in an area prone to ticks, assume you’ve picked one up. Do a thorough check when you’re back indoors and remove any ticks immediately.