Your chances of a Lyme or West Nile infection are lower than you think. But prevention is still important, including checking for bites and watching for symptoms.
After finding at least one tick himself hiking in the woods, Matthew Grant, MD, has become diligent about checking.
(July 2013) As eager as we are for the picnics, barbecues and pool parties to begin, we know the danger posed by Lyme disease, West Nile virus and other insect-borne illnesses is already lurking. This summer, there is even a new tick-borne disease out there—a distant yet-to-be named cousin to Lyme disease reported by Yale researchers in January.
The good news is that the risk of getting Lyme disease from a recognized tick bite is relatively low, says Yale pediatrician and epidemiologist Eugene Shapiro, MD. Only one to three percent of those who recognize they’ve been bitten get the disease—usually when they see the “bulls-eye” rash a week or two later. “That’s because most ticks are not infected, and if a tick is infected, it has to feed for some time before it can transmit Lyme Disease,” says Dr. Shapiro. “For a nymphal tick, it’s 48 hours or longer before the risk of transmission is great. For adult ticks, it’s 72 hours or longer. So, if you see the tick before that and pull it off, you most likely will not get the disease.”
Of course, Dr. Shapiro says, “It’s the tick you don’t see that poses the greatest risk.”
West Nile virus disease is even less common—there were 21 cases reported in Connecticut last year, compared with 1,654 reported cases of Lyme—although that is notably the most severe outbreak of West Nile since the virus was first detected in the state in 1999, and more than double the cases reported in 2011. “In my practice, there’s more regional concern about Lyme. In Connecticut, it’s very common to know someone who has had it,” says Matthew Grant, MD, a Yale infectious disease specialist.
Eugene Shapiro, MD, examines a baby. He says the risk of serious West Nile virus infections is highest in the youngest and the oldest patients.
You are less likely to get these diseases if you take precautions and see a doctor quickly with suspicious symptoms. A few things to look for:
West Nile virus: You may experience no symptoms at all, or you may turn out to be the one out of five who develop a fever. A minority have headaches, body aches, joint pains, vomiting or diarrhea. More worrisome is that the disease can lead to encephalitis or meningitis, and can be life-threatening especially to the elderly and the chronically ill. There is no vaccine or specific antiviral treatment, although over-the-counter pain relievers can be used to lessen some symptoms.
Lyme disease: Symptoms vary. You may notice an expanding red or bull’s eye rash at the site of the bite, as well as flu-like symptoms such as chills, fever, body aches, fatigue and headaches. The latter symptoms are so common and nonspecific that they can make diagnosis difficult. But untreated, early Lyme disease can develop into arthritis, or neurologic or cardiac disorders. Talk to your doctor about whether you might have Lyme disease. If the disease is diagnosed, the doctor will typically prescribe doxycycline or amoxicillin, or, rarely, intravenous antibiotics. Yale’s Peter Krause, MD, a tick-borne disease researcher, recommends talking to a doctor about a single dose of doxycycline for adults and children 8 years and older in certain circumstances following a deer tick bite.
A new Lyme-like disease:
In January, Dr. Krause, Yale researchers Erol Fikrig, MD, Durland Fish, PhD, and Sukanya Narasimhan, PhD, along with colleagues from other institutions, reported in the New England Journal of Medicine the first description in the United States of the occurrence, frequency and clinical manifestations of a tick-borne infection that shares many similarities with Lyme disease. This disease, which is still rare, is caused by the bacterium Borrelia miyamotoi, and causes many symptoms similar to Lyme, although there may be other symptoms, such as a relapsing fever. Blood tests for this infection are only available in a few laboratories, but many laboratories are planning to offer the test in the near future. The disease is treated with the same antibiotics that are used for Lyme disease.
While it helps to be aware of these diseases, Dr. Shapiro says they shouldn’t keep you from going outside this summer. “The anxiety is as large a problem, or larger, than Lyme disease itself,” he says. “There is a lot of misinformation in the lay press and on the internet, and misdiagnosis is rampant. The thing to keep in mind is that Lyme disease is fairly easy to diagnose and cure, and if it’s treated effectively there is little risk of long-term complications.”
The trick is to be careful, says Dr. Grant. He’s had personal experience. After a hike on the Connecticut shoreline, he and his wife checked themselves for ticks in the parking lot and found a nymphal tick on his lower right shin. He used a pair of tweezers to remove it. “Ticks need to be engorged to infect you, so if you go on a hike, spot a tick and then remove it immediately, you don’t have to worry,” Dr. Grant says.
Photos by Robert A. Lisak
Yale Physicians Building
800 Howard Avenue, 3rd Floor
New Haven, CT 06519
The best prevention for Lyme disease and West Nile virus is to follow recommended precautions and avoid summer’s stings.
Use bug spray: Yale experts recommend using insect repellent containing 30 percent DEET during extended periods outdoors. Eugene Shapiro, MD, tells parents to avoid the face and wash children’s hands after applying repellent.
Protect your environment: Dump or drain any standing water around your home. Install screens and repair torn ones to prevent mosquitos from coming indoors. Take extra care in the evening and early morning (peak biting times). Keep your lawn mowed and free of leaf litter.
Dress strategically: Lyme disease experts advise wearing light-colored socks, long sleeves and pants with cuffs tucked in when you go out in the woods. You can choose to spray permethrin on your clothes. Remember that repellents wear off in a couple of hours, so you should check directions on how often to re-apply them.
Find and remove ticks: If you’re outdoors, check your entire body, including the scalp at least twice a day. Matthew Grant, MD, recommends keeping a pair of tweezers on hand when you roam around fields or woods. If you find a tick on your body, use the tweezers to grasp the tick as close to the skin as possible. Try not to injure the body of the tick. Pull perpendicular to the skin with a steady pressure. Don’t twist. If possible, put the engorged tick in a bag and take it to the doctor. “You may be a candidate for a single dose of antibiotics,” Dr. Grant says, “and you’ll need to pay attention to the area for the next couple of weeks to look for a rash.”
Credit: The American Lyme Disease Foundation
The American Lyme disease Foundation (ALDF), with strong Yale participation, maintains a website with information about Lyme disease. The site has sections on programs and services, news and topics of interest.
ALDF also offers an iPhone application, the Lyme disease Tick Map, which includes information on the abundance of infected ticks at the user’s location. A tick identification chart is provided with life-size photos of deer ticks, so each life stage can be determined, because Lyme disease can only be transmitted at certain stages. There are instructions on how to remove a tick, along with a video, as well as photos of ticks at different stages of engorgement. A tick must be attached for 48 hours or longer for Lyme disease to be transmitted. Visit the www.aldf.com to access the free Lyme disease Tick Map iPhone app.