More Ticks Than Ever This Year? Unclear, But Already Enough For Abundance Of Caution

A blacklegged tick (Stephen Reiss for NPR)
A blacklegged tick (Stephen Reiss for NPR)

When Catherine Graciano was recently out walking Seamus, a fluffy Malamute-Chihuahua mix, in Wellfleet near the tip of Cape Cod, she found a dozen big ticks crawling in the dog's white fur after only 20 minutes. She said lately she's been finding more ticks than last year on her own body, too, after runs in the Cape's parks.

Just finishing a walk in Peterson Farm in Falmouth, herbalist Lauren Valle said these days, she thinks twice before foraging in the woods for nettles, because she's heard that ticks are expected to be a bigger problem than usual this year. She's 11 weeks pregnant, and wouldn't want to have to undergo Lyme disease treatment if a tick infected her.

As she chatted, Valle’s walking partner, Elise Hugus, began checking around her own leggings for ticks. “The power of suggestion,” she said.

Even within the city of Boston, residents have reported striking tick encounters in recent days. Kelley Ready of Dorchester's St. Mark's neighborhood took a stroll on the nearby Neponset Trail with her friend, Urjasi Rudru, and Rudru's big orange dog, Simba. Simba was leashed and stayed on the trail, but, inquisitive, stuck his nose into the reeds and grass. Later, Ready reported on a neighborhood forum, Simba's head and paws were infested with well over a dozen ticks, and Rudru found more on him the following day.

Warm weather ticks are nothing new, but "this just seemed really extreme to me," Ready said.

It has become an annual springtime ritual in Massachusetts, one of the states most heavily affected by Lyme disease and other tick-borne illnesses, to wonder whether the emerging tick population is bigger than ever. This year, those concerns gained added fuel from an ecologist's prediction that this will be a particularly heavy tick year in the Northeast, and thus heavy for the diseases they carry as well.

A white-footed mouse, left, and a blacklegged tick (Stephen Reiss for NPR)
A white-footed mouse, left, and a blacklegged tick (Stephen Reiss for NPR)

Richard Ostfeld, of the Cary Institute of Ecosystem Studies, observed that heavy acorn production one year leads to high numbers of white-footed mice the following year. With more mice to feed on, the populations of deer ticks that spread Lyme disease boom. In the area in New York that Ostfeld studies, he saw high numbers of acorns in 2015, a boom in mice in 2016, and so is expecting large numbers of ticks in 2017.

It's too early to tell whether Ostfeld's prediction is coming to pass, but for federal and state officials, now is the time to issue warnings — no matter the ultimate numbers. The Centers for Disease Control and Prevention have just issued a press kit noting that an estimated 300,000 Americans are infected with Lyme disease each year, and while it's difficult to predict how bad a specific season will be, it's known that the highest infection rate is from May to July.

“We have infected ticks across Massachusetts every single year, and every year we have more cases than I would like us to have,” said Catherine Brown, the state's public health veterinarian. “It really doesn’t matter whether there’s a few more ticks,” she continued. “Every year, there’s a good chance you can be exposed to Lyme disease.”

So whether tick populations are up or down, “use tick repellent and do tick checks,” Brown recommended.

Predictions and tick counts are difficult because even if there’s a high number of ticks in one place, it doesn’t mean populations will be up statewide.

“Tick populations tend to be very localized,” Brown said.

And getting data on tick populations isn’t easy, requiring scientists to drag white flannel squares on the ground for 30 seconds, then count the number of ticks that latch on, then repeat the process multiple times in various locations to get a general sense of the tick density.

“If you do that in one person’s lawn you may get nothing, but across the street you may see a totally different result,” Brown said.

Ostfeld, of the Cary Institute, confirmed in an email that it is too early in the tick season to know whether his prediction is coming true. Also, ecological data on acorn production or white-footed mice populations in Massachusetts are lacking, he said, leaving experts guessing about possible effects.

Still, it is clear that many people are more vigilant than usual this spring. Steven Rich, a professor of microbiology at UMass-Amherst and director of the Laboratory of Medical Zoology, runs a testing laboratory for ticks. People can send ticks — preferably in zip-lock bags — in to the lab, where for $50 they can be tested for the three most common tick-borne diseases: Lyme, and two other potentially serious illnesses, babesiosis and anaplasmosis.

Last year, the lab tested 7,000 ticks, Rich said. This year, it's on pace to receive about 10,000.

The lab has tested 250 ticks from Barnstable so far this year. (Barnstable County subsidizes the cost of the tick testing with a community grant from Cape Cod Healthcare, so residents pay just $15 per tick.) It found that almost 39 percent of black-legged ticks carried the bacteria that causes Lyme; babesia was found in almost 10 percent, and anaplasma found in over 5 percent.

Rich is quick to point out that increased numbers of tested ticks might just mean that people are more aware of the tick problem, not that there are more ticks. But he welcomes the chance to make people even more aware, about both the risk and prevention: “When a worried mom sends her 4-year-old’s tick, they are primed to hear everything we can tell them about that tick, and how to avoid the next one."

Tick awareness is already high on Cape Cod, where it can sometimes seem like virtually everyone has had Lyme disease at least once. Rich is all in favor of awareness, but says it doesn't need to cross over into fear.

“A tick bite is not like a lightning strike,” he said. “Ticks are something you can take precautions to mitigate the risk.”

Along with all the usual recommendations for prevention, he pointed out that even if someone does find a tick on their body, there is a lot they can do. “You can still take action,” he said -- taking the tick off using pointy tweezers, for example, or grabbing the tick by the head and pulling straight out without twisting.

Graciano, who has been finding more ticks than usual on herself and her dog Seamus lately, says she takes active joy in getting rid of them.

“I light them on fire and flush them down the sink,” she said. “They pop and blow up a little bit.”



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