CHAPEL HILL, N.C. — In the trees and grasses of the South, there are a growing number of unwanted visitors that at best are an itchy nuisance and at worst can carry debilitating diseases: Ticks.
Public health officials say that numbers of reported cases of diseases like Lyme disease and Rocky Mountain spotted fever are not yet alarming and have not yet shown a definitive trend upward from a national perspective. But they do worry that more ticks means more of a risk that those diseases will spike.
And scientists are finding species of ticks not seen before in the region – just ask pediatric nurse Maria Mekeel, who has plucked 37 of the arachnids off herself and her husband over two months of dog walks.
The changes can be traced to 2009, when scientists found the Ixodes Affinis tick in North Carolina. The parasite, native to South America, had been previously seen only in coastal Florida and Georgia. That particular tick doesn’t bite humans, but it will bite animals. And scientists say a higher rate of disease in animals can make easier for other ticks to transmit to humans.
“Ticks are spreading, but usually not like wildfire,” said Joseph Piseman, chief of tickborne disease activity for the federal Centers for Disease Control and Prevention. “The spread is kind of slow but sure.”
Lyme disease is serious: It can cause paralysis, heart palpitations and death in extreme cases.
“We’re not talking about STD rates, but it’s common enough that people should be concerned,” said Charles Apperson, an entomologist who has studied ticks for three decades.
There are at least two other types of tick to contend with: The Gulf Coast variety and the Lone Star tick, common in its namesake state of Texas. The Gulf Coast tick, which until recently was not typically found as far north or east as North Carolina, carries a disease similar to the bacteria that causes Rocky Mountain spotted fever.
The Lone Star tick carries a flulike infection, and Apperson said the main reason for its emergence in the region is a larger population of deer for it to feed upon. Scientists aren’t so sure about why other species are invading, however.
There is a national trend of an increasing number of ticks. Piseman said the Ixodes Affinis variety has been expanding in New York and Wisconsin, and Lone Star ticks have been spreading across the U.S. for decades.
For the most part, scientists are not yet examining why the populations have been spreading, said entomologist Bruce A. Harrison, who studied ticks for the state of North Carolina for nearly 20 years. He hypothesized it may be at least in part caused by climate change. As temperatures change, animals that are food for ticks migrate – often because the plants they eat are now growing elsewhere.
“All of it’s hooked together,” said Harrison, who is studying the migration patterns of animals that ticks feed upon to learn more about how and why the arachnids are spreading.
Although the CDC hasn’t reported a spike in tick-borne diseases, officials in North Carolina have noticed an increase this year compared to a year earlier. Rocky Mountain spotted fever cases are up 50 percent this year, said state public health veterinarian Carl Williams. And while there typically wasn’t a single positive Lyme disease test 10 years ago, now there are a few each year, Mekeel said.
For now, the best tool is education. Mekeel has put those 37 ticks she plucked off herself and her husband into a petri dish, which she uses to teach schoolchildren about ticks. If kids roll around on the ground, the ticks can latch on in tough-to-find spots like hair or the groin area, said Mekeel, who has 22 years of experience as a pediatric nurse.
“We’ll have children that will come in with maybe one hundred ticks on them at a time, not always, but it happens,” she said. “I’ve actually had a family that went away on vacation and put their clothes away in the laundry room and came home after a week and their laundry room was covered in ticks that had hatched in their clothes.”