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Deer ticks pose year-round threat

Deer ticks pose year-round threat


BLACKSBURG — Ottoline Bushey doesn’t know when she was bitten by the black-legged tick that gave her Lyme disease last July, but she said she’s just relieved it gave her a rash.

Otherwise, Bushey said, she might not have been treated so quickly for the condition.

“I had a fever. I felt awful — like I was dying,” Bushey said.

At first, she said she assumed it was the stress of moving to a new home. But then she found the rash on her leg. About half of people who fall ill find no rash, making diagnosis more difficult. But when the rash is present with other symptoms, doctors typically treat immediately with antibiotics.

Bushey said she’s pretty sure she picked up the tiny, infected arachnid somewhere near her home in Blacksburg’s Village at Tom’s Creek, surrounded by forest with a high population of the black-legged — also known as deer ticks. And knowing they’re out there has been unsettling.

“It’s greatly changed our attitude to how we feel about being outdoors,” she said.

Bushey used to garden often, but said she’s now reluctant. She said she forbids her children to play in the nearby woods.

And now, she said she wonders if the lingering sore throat, swollen lymph glands and fatigue she suffers are related to Lyme. She’s heard about the idea of so-called chronic Lyme, which many health care professionals say does not exist.

Bushey said she took antibiotics for about a month and “felt hugely better after about a week.”

“But it does make one wonder,” she added.

Controversy between the two sides of the so-called chronic Lyme debate continues, with few definitive answers.

“There’s still a lot we don’t know about this disease,” said Dr. Molly O’Dell, medical director of the New River district of the Virginia Department of Health.

But one thing is known: As populations of black-legged and other ticks expand, rates of tick-borne infections among people and pets are increasing.

Top three disease

Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of infected black-legged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash. If left untreated, infection can spread to joints, the heart and the nervous system.

First identified in Lyme, Connecticut, in the 1970s, Lyme disease has spread into Southwest Virginia with black-legged ticks and their major host, the white-tailed deer. Expanding deer herds have in recent years pushed into newer suburban areas where food is abundant, bringing the ticks with them.

In 2013, Virginia had an incidence rate of 11.2 confirmed cases of Lyme disease per 100,000 people, according to the U.S. Centers for Disease Control. That’s much higher than in many states but much lower than in the Northeast, which remains the epicenter.

Virginia’s numbers have risen dramatically since, from a total of 216 cases in 2004, according to the CDC, up to 1,346 last year, according to David Gaines, state public health entomologist for Virginia. A similar trend is playing out in the New River Valley.

Communicable disease surveillance by the Virginia Department of Health’s New River Health Districtshows that Lyme has become “one of the top three reportable diseases in all the localities,” O’Dell wrote in an email.

Another tick-borne illness, ehrlichiosis, is “an emerging public health concern,” O’Dell said.

Ehrlichiosis refers to a cluster of related infections that can be spread by the lone star tick, a species prevalent in the Roanoke area and east of the Blue Ridge. It’s not considered a common species west of the Blue Ridge, Gaines said.

Last year there were 125 reported cases of ehrlichiosis and eight of another tick-borne illness called anaplasmosis, according to Gaines.

Ehrlichiosis symptoms include fever, headache, chills, malaise, muscle pain, gastrointestinal distress, confusion, red eyes and a rash in about a third of adult sufferers and more than half of children who contract it, according to the U.S. Centers for Disease Control and Prevention. It can be fatal in some cases, but early treatment with antibiotics is typically effective.

In the past, health officials saw a “case here and a case there” of Lyme, O’Dell said. In 2004, according to health district figures, there were zero cases of Lyme reported in the four counties and one city of the New River Valley.

In 2005, two Lyme cases were reported in Montgomery County. But by 2014, the number of reports rose to 72 — the highest infection rate in the valley. Other localities have seen increases, with Radford and Giles County showing relatively low rates, according to the figures.

The same kind of slow start, but rapid increase could happen with ehrlichiosis, O’Dell said.

Understanding the spread of tick species and tick-borne illnesses into new areas has become more important with shifts in land-use patterns and weather and climate changes.Relying on old information can be dangerous, as one New River Valley tick study suggests.

Year-round threat

In the past, worries about ticks were confined to the warm months, when the American dog, or wood tick, was known to be looking for hosts. But black-legged ticks are a cold climate species, having emerged in the Northeast.

“A freezing year slows down their activity,” said Anne Zajac, a Virginia-Maryland College of Veterinary Medicine parasitologist. “But it doesn’t kill them.”

Their spread to Virginia has been quite recent, too. For the past 15 years, Zajac said she has taught a spring semester parasitology course at the vet school beginning in January.

“I used to have a contest for the first tick of the season. The first student to find a tick on their dog could bring it in and get an extra credit point,” she said. “Usually, in March I’d get a dog tick; never the deer tick.”

But Zajac said recently there are so many ticks out there in winter — including the black-legged ones — that she’s had to stop the contest.

Zajac doesn’t specialize in ticks, but the Giles County resident became interested in them after finding a Gulf Coast tick — not a tick usually found in Southwest Virginia — on her cat. Zajac mentioned it to her pet groomer and noted Lyme victim advocate Mauricia Shanks.

Together they decided to do a tick survey. Three times from October 2012 through April 2013, the pair did “tick drags” in three spots in Giles and Pulaski counties. They chose grassy spots that transition into woods — known to be favorite places for ticks.

Using a standard-sized piece of cloth pulled through vegetation for a standard period of time, the pair caught no Gulf Coast ticks, but netted 369 adult black-legged ticks. They sent the specimens to Susan Little of Oklahoma State University — an alumna of Tech’s vet school — for laboratory testing.

Little found that more than 30 percent of the ticks collected tested positive for the Lyme agent, and less than 1 percent were found positive for another tick-borne illness, anaplasmosis.

The results surprised Zajac.

“I’m a strong believer now in year-round tick control, having seen how numerous deer ticks are in the wintertime,” Zajac said. “If the temperature was above 40, the ticks were out there, ready to attach.”

Zajac published the results last year in the journal Vector-Borne and Zoonotic Diseases.

“I don’t want people to be paranoid,” Zajac said. But it’s important — for their pets and for themselves — to be aware, she said.

Other experts also advocate calm vigilance and prevention, for people and for pets.

First off, there’s no evidence that keeping pets increases the risk of tick-borne illnesses, according to Dr. Julia Murphy, state public health veterinarian.

But dogs do develop Lyme disease, and show similar symptoms to those in people, said Dr. Mark Freeman, professor of community practice at Tech’s vet school and a clinician at the school’s small animal hospital. (No signs of clinical Lyme disease have been identified in cats, experts say.)

“This is a hotbed for Lyme disease in Virginia,” Freeman said of the New River Valley. The infection rates for both people and dogs are thought to be similar, Freeman said. But it’s unclear how fast the infection rate is rising in dogs.

“We are seeing more positives, but we’re also testing more dogs,” Freeman said.

There are no reporting requirements for Lyme in animals, and data are spotty, he said.

Also, dogs that have never shown clinical symptoms can test positive for Lyme. Freeman said the thinking is that dogs may be better able to fight the infection. But keeping them tick-free is still important. Lyme infection may contribute to kidney damage in dogs, Freeman said.

“Prevention is the key,” Freeman said. “None of the tick preventatives we had available up until recently protected against the deer tick.”

Dogs are given the same antibiotic therapy for Lyme as people. There are also effective products — from repellent collars to oral flea and tick medications, Freeman said. Most veterinarians recommend treating dogs year-round to prevent bites.

Freeman said he also recommends Lyme vaccination for most dogs, which includes two shots over three to four weeks with annual boosters.

There are ways people can reduce risks, too, experts say.

Know your tick

To reduce the chances of contracting a tick-borne infection, understand what ticks could be near you.

As a woodland species, the black-legged tick needs shady areas and typically is found in the leaf litter of woodlands or on bushes on woody edges, according to Gaines, Virginia public health entomologist.

Know the ticks’ life cycles and when risks are highest. In Virginia, May 1 to the end of June is the season of the black-legged tick nymph, and the most likely time for people to catch Lyme, Gaines said.

The black-legged tick goes through four life stages over a two-year period, and picks up the Lyme agent in its second, or larval stage. Larva seek out woodland rodents, especially the white-footed mouse to take a blood meal. Rodents are the reservoir for Lyme; once infected, the ticks merely pass it on, Gaines said.

All but one stage of the black-legged tick have strong preferences for their hosts, and so target specific animals. But nymphs are different. They are known to feed on about 100 different kinds of hosts, and will readily bite humans.

Adult black-legged ticks are active in the colder months, but the incidence of Lyme drops significantly in winter, Gaines said.

Adult stage black-legged ticks are most interested in finding their preferred host, a white-tailed deer, when it’s colder. Deer do not carry Lyme, but black-legged ticks mate on deer and then females take a blood meal before dropping off to lay eggs.

Ticks are not everywhere, either, Gaines said. Black-legged ticks need humidity to survive, and aren’t found in sunny areas with short vegetation, he said.

Land-use changes are a major contributor to the increase in Lyme.

“If you want to get a lot of ticks on you, go to suburban areas,” Gaines said. “There are more deer in suburbia, and the more deer, the more [black-legged ticks] you’re going to have.”

Gaines said past tick surveys he’s done in Blacksburg found high numbers, but other suburban areas of the state have high populations, too.

Black-legged ticks are not the only species of concern. The lone star ticks are widespread in Roanoke and areas east of the Blue Ridge Mountains, and carry other ailments. They can even cause a rare, permanent allergy to red meat.

Eric Day, director of Virginia Tech’s insect identification laboratory, sees a lot of ticks in his job. Most of the specimens are sent to him through Virginia Cooperative Extension offices across the state.

Not only have black-legged ticks expanded into the region, but Day said the Gulf Coast tick — unheard of here in the past — has now been found in Virginia.

“Some are showing up in Giles County,” Day said. “It’s a new distribution.”

Unlike the black-legged tick that needs shade and humidity to survive, the Gulf Coast species, or Amblyomma maculatum, can live in hot, dry conditions, Gaines said.

New health concerns are likely to follow it into Virginia.

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