Much of what Lehigh Valley doctors believed about deer ticks and the disease the tiny parasites spread was based on assumption.
New Jersey to the east and central Pennsylvania to the west both had plenty of Lyme disease-carrying ticks, so the Lehigh Valley, sandwiched in between, must have them too.
But how prevalent is Lyme in the Lehigh Valley?
That’s an important question, especially this time of year when so many people head outdoors to hunt, hike and enjoy the foliage, but nobody knew the answer.
Now we do, thanks to Marten Edwards, a biology professor at Muhlenberg College in Allentown, and his team of intrepid undergraduate researchers who have scoured the region for ticks, capturing thousands and performing the meticulous work of extracting and analyzing their DNA.
Twenty-three percent of Lehigh Valley ticks in their sample were infected with Lyme. That’s more than 1 in 5, which is the threshold at which public health officials consider the risk of infection to be “particularly serious,” Edwards said.
“It’s a significant medical challenge for the public,” said Dr. Luther Rhodes, chief of hospital epidemiology at Lehigh Valley Health Network. “It’s a concern that scares a lot of patients. It drives a lot of doctor visits.”
Rhodes said Edwards’ findings are the Lehigh Valley’s first-ever “hometown data” on ticks. “There’s nothing better,” he said. “We get asked, ‘What’s going around?’ It’s nice to be able to give straightforward answers.”
Each year, more than 300,000 Americans, mostly in the Northeast and upper Midwest, are diagnosed with Lyme, making it the most common vector-borne illness in the United States, according to the Centers for Disease Control and Prevention. Pennsylvania topped the list for confirmed cases of the disease for three years in a row, according to the state Department of Health’s most recent Lyme report which was released last year.
In 2014, Pennsylvania counted 7,400 cases of Lyme disease, a 25 percent increase from 2013, the report noted. Lehigh and Northampton counties tallied 224 total cases. Regionally, the numbers were much higher in Bucks and Montgomery counties, slightly higher in Berks County and much lower in Carbon and Schuylkill counties, the report showed.
Edwards’ ongoing research, which was the basis for a paper published last year in the peer-reviewed journal Ticks and Tick-Borne Diseases, illustrated the depth and extent of the Lehigh Valley’s Lyme problem.
Also detected, though in much lower frequency, were the pathogens behind two other infectious diseases: anaplasmosis, caused by another species of bacteria, and babesiosis, caused by a malaria-like protozoa that infects red blood cells.
Overall, the Lehigh Valley’s tick and disease profile is similar to that of the rest of Pennsylvania, Edwards said. As such, it stands in contrast to some nearby areas, such as eastern Ohio, where Lyme is relatively rare despite the relatively high frequency of deer ticks, or New York’s Hudson River Valley, where not only Lyme but also babesiosis and anaplasmosis are more common.
This kind of local information helps infectious disease doctors in the area diagnose health problems and prescribe treatment plans. “We know what is practical to test for,” Rhodes said.
LVHN’s chief of hospital epidemiology, it turns out, has more than one connection to Edwards’ research: He is not only its beneficiary but also its benefactor, as it was funded in part by a grant from LVHN’s Luther V. Rhodes III, M.D., Endowed Fund in Infectious Diseases.
Rhodes established the endowment with a $1 million gift to LVHN in 2009 and is clearly pleased with the Muhlenberg team’s work. “What they have done, they have done very well,” he said.
The findings are helpful to Louise Bugbee as well, since part of her job with Lehigh County Penn State Cooperative Extension is to educate the public on the risks posed by ticks. She said the Lehigh Valley-specific information gleaned makes it that much easier for her to make a connection with her audiences, which range from public officials to garden club members.
“Peoples eyes light up, and they say, ‘Oh, yeah, I get it,'” she said. “When you can say 1 in 5 ticks … It gives them a real way of assessing their risk.”
The Ticks and Tick-Borne Diseases paper published last year was based on field work in Lehigh, Northampton and eastern Berks counties at eight popular hiking areas such as the Franko Farm Recreational Area in Salisbury Township and the Bob Rodale Cycling and Fitness Park near Trexlertown.
Before going into the field, Edwards and his students treated their clothing and shoes with Permethrin, a tick repellent that Edwards swears by. After spending 160 hours in some of the most tick-infested parts of the Lehigh Valley, Edwards said he has yet to get a single tick bite. None of his students has either.
To find ticks, the research team had to delve deep into the brush and leaf litter that is prime deer tick habitat, dragging a sheet of white corduroy along the ground. Ticks climb aboard because the fabric resembles mouse fur. One of the best times is early summer, when the woods are flush with tick nymphs.
“I’ve been interested in bugs that bite people for more than 20 years,” said Edwards, whose other areas of expertise include mosquitoes that spread Zika. “It’s funny, when you’re looking for ticks, you’re actually very excited to find them.”
The nymphs, which may be smaller than a fleck of pepper, stand out against the white corduroy and were removed using tweezers and immersed in rubbing alcohol, which quickly kills them. (As an extra safety measure, Edwards insists his students shower and change their clothing immediately after field work.)
Back at Muhlenberg College, the students performed lab work with sophisticated scientific tools — as well as some that weren’t so sophisticated, such as a mortar and pestle to grind the ticks into mush.
After extracting the DNA, they analyzed it with the help of statistical software program..
“I wanted something outside of the classroom,” said biology major Emily Davidson, explaining why she chose to participate in the project, which required her and a handful of other students to work as paid interns 40 hours a week over the course of the summer.
The commitment has continued into the fall semester. “I think our students spend more time in the lab than at parties,” Edwards said.
The research did not detect a significant difference in the prevalence of Lyme-causing bacteria in the various parts of the Lehigh Valley. Essentially, it’s a serious problem throughout, Edwards said.
By comparison, the pathogens that cause babesiosis and anaplasmosis, both of which result in flu-like symptoms, present a lower risk — but a risk nonetheless. Neither are present in more than a small percentage of Lehigh Valley ticks, according to Edwards.
Lyme disease is named after the town of Lyme, Conn., where it was discovered in 1975. The prevalence of deer ticks — and Lyme — has spread since then. Last year, the Pennsylvania Department of Environmental Protection announced that deer ticks had been observed for the first time in all of the state’s 67 counties. Similar studies conducted in the mid-1960s found no specimens.
Symptoms of the disease include headaches, fatigue, joint swelling, muscle pain and gastrointestinal distress. Often the first sign is a rash that looks like a bull’s-eye at the site of the tick bite. If left untreated, Lyme infections can spread to joints, the heart and the nervous system and are often misdiagnosed as other serious ailments, including fibromyalgia, chronic fatigue syndrome and multiple sclerosis.
Edwards began his Lehigh Valley tick and Lyme survey in 2013, and he plans to continue it. That way he’ll be able to gauge any changes over time in the size of the tick population and rates of infection for Lyme, babesiosis and anaplasmosis.
“Things have changed dramatically over the last few decades, which is a very short period of time in the grand scheme of things,” Edwards said. “We expect them to change in the future. The only way to know is to look.”