June 7, 2001 -- For those living in the Northeast and Upper Midwest, this summer promises to be another active one for ticks carrying Lyme disease.
"Lyme disease continues to be the most commonly reported tick-borne disease in the U.S.," says Ned Hayes, MD, a medical epidemiologist in the CDC's division of vector-borne infectious diseases, located at Fort Collins, Col.
Numbers of cases increased steadily over the 1990s, with 16,000 reported in 1999, Hayes tells WebMD. "Preliminary totals indicate that the year 2000 will probably be close to that figure."
Lyme disease most commonly affects people in New England, the Mid-Atlantic States, and the upper Midwest states of Wisconsin and Minnesota, says Hayes. It is transferred to humans by deer ticks living in grassy, wooded areas. The highest-risk months are May and June, but risk does continue throughout the summer, he tells WebMD.
"People living in those areas should be taking precautions," Hayes says. And that could include the Lyme disease vaccine, early detection and removal of ticks, and reducing the number of ticks infesting private properties.
For starters, the CDC offers the following advice:
- Wear light-colored clothing so ticks will be clearly visible and can be easily removed.
- Keep ticks from reaching the skin by wearing long-sleeved shirts. Also, tuck pants into socks or boot tops.
- Wear rubber boots, since ticks are close to the ground.
- Protect exposed skin with insect repellents containing DEET; applying permethrin to clothes will kill ticks on contact.
- Make yards less suitable for deer, rodents, and ticks. Remove leaf litter as well as brush-and-wood piles around houses and at the edges of yards. Clear trees and brush to allow more sunlight to the yard.
- Install a barrier of wood chips where lawn meets forest; ticks don't survive well on chips.
- Remove any plants that attract deer.
And regarding the vaccine, the CDC recommends it for anyone between the ages of 15 and 70 who lives in a high-risk area and has exposure to tick-ridden habitats, Hayes tells WebMD.
But the vaccine is not without controversy.
Since its FDA approval in 1998, nearly 1,000 complaints from patients have been recorded; about 70 of those cite arthritis-like side effects.
While the adverse reactions continue to be reported, "there have been no clear patterns," says Lenore Gelb, spokesperson for the FDA. "We'll continue to do surveillance. [The reports] could point to something very rare," like a genetic predisposition to having problems with the vaccine.
"Everybody feels that more study is needed," Gelb tells WebMD. "We are concerned about it, yet it's difficult because some of these arthritis symptoms are very common and hard to pin down. It's not like a specific, unusual side effect. And it was nothing we saw in clinical trials with thousands of people."
At this point, hypersensitivity reactions -- similar to allergic reactions -- are the only changes that might be made to the vaccine's physician labeling, says Gelb.
"We know there is a controversy out there," says Carmel Hogan, spokesperson for Glaxo SmithKline. "But all our surveillance data and evidence from our clinical trials establishes LYMErix to be safe and effective. Our position hasn't changed."
The company is embarking on a phase IV, or postmarketing, clinical trial of the vaccine, to comply with all FDA requirements, Hogan tells WebMD. Thus far, 4,000 people have been identified with a goal of enrolling 15,000.
"We continue to monitor this," says Hogan. "But we currently have no scientific evidence to suggest that any [serious side effects] exist beyond those which has already been included on the label."
While investigations continue on the vaccine front, it's a good idea to be sure you are up on the features of Lyme disease.
A bull's-eye rash is most characteristic, followed a few months later by arthritis as well as brief bouts of pain and swelling in one or more large joints, especially the knees. Lyme disease is not fatal, but it can have long-term effects including destruction of joints and nervous system disorders. However, with early diagnosis and treatment, serious consequences can be kept at bay.
High-risk areas include those where deer and white-footed mice and ticks are abundant, Hayes says. That includes brushy and wooded habitats, especially those where forest edges meet lawns and meadows.
To help prevent Lyme disease, people living in high-risk areas should avoid tick-infested areas, says Hayes. Also, early detection and removal of ticks is important. If it's necessary to go into high risk areas, use repellant and check for ticks at the end of the day.
"Prompt removal of ticks will help avoid infection, because the tick has to be attached for two to three days for infection to occur," he says.
The CDC also is testing bait devices that give deer or rodents a pesticide application, says Hayes. These devices are not yet commercially available.