Hiking hobbyist Dr. Linda Sigmund knows the precautions for avoiding contracting Lyme disease from tick bites. Even so, she got an infection last summer during a hiking trip in Warren County, Va.
The Arlington resident thinks that after she and her hiking partners checked each other for ticks, a tick that was on her dog, Spencer, a 13-year-old cocker spaniel, landed on her. She became infected with the Borrelia burgdorferi bacterium, which causes Lyme disease.
“It’s usually a mild illness if it’s diagnosed and treated appropriately,” says Durland Fish, board member of the American Lyme Disease Foundation (ALDF), a nonprofit organization in Somers, N.Y., that funds research and provides information on the disease. “If not, it can become a serious and debilitating disease.”
Dr. Sigmund, a neurologist at the Neurology Center of Fairfax, began experiencing hip pain two to three weeks after the Independence Day weekend hike. She figured she had overextended herself, but the pain continued, and she felt fatigued.
Dr. Sigmund went to see Dr. Mary Schmidt, an infectious disease specialist at Inova Fairfax Hospital in Falls Church, and was treated for Lyme disease, first with oral antibiotics and then with more than four weeks of intravenous antibiotics.
“It was horrible,” Dr. Sigmund says. “I was absolutely exhausted.”
Lyme disease is carried by black-legged ticks, also known as deer ticks, in the Northeastern, upper Midwest and mid-Atlantic states and by Western black-legged ticks on the Pacific Coast. Deer ticks become infected by the Borrelia burgdorferi bacterium when they feed on infected deer and white-footed mice, their preferred hosts.
The number of cases of Lyme disease, which was first recognized in 1975 in Lyme, Conn., is increasing as the size of the area affected by the disease also expands. The number of cases increased 40 percent from more than 17,000 cases in 2001 to more than 23,000 cases in 2002, as reported by the Centers for Disease Control and Prevention (CDC) in Atlanta.
Though there has been some fluctuation, the number of cases has increased over the past decade because of greater awareness and increased reporting, says Dr. Paul Mead, medical epidemiologist for the Division of Vector-Borne and Infectious Diseases at CDC.
In addition, “The deer populations, which are important for maintaining tick populations, are at historic highs,” Dr. Mead says.
The highest risk for Lyme disease is in the Northeast, in particular in Maryland, New Jersey, Connecticut and Pennsylvania, says Dr. Schmuel Shoham, infectious disease specialist at the Washington Hospital Center in Northwest. Northern Virginia and the Virginia Beach area also are at risk, he says.
“The tick is not found everywhere,” Dr. Shoham says. “It’s usually found in areas where there are mice and deer.”
The peak transmission season is at the end of May or the beginning of June, when nymph-stage ticks, the size of a poppy seed, are active, says Mr. Fish, professor of epidemiology at the Yale School of Public Health in New Haven, Conn. He holds a doctorate in etymology and zoology.
The adult ticks, which are the size of a sesame seed, are active in the colder months, from October to April, Mr. Fish says. Both nymph and adult ticks can transmit Lyme disease, according to the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health in Bethesda. About 1 percent of deer ticks are infected with the bacteria, according to NIAID’s Web site (www.niaid.nih.gov).
The peak transmission season for ticks in the metro area is from February to October because of warm springs and falls, Dr. Schmidt says.
In other areas, the season lasts from May through August, according to the CDC’s Web site, www.cdc.gov.
An infected tick needs to feed for at least 24 hours before the bacterium, which lives in the intestines and salivary glands of the tick, can be transmitted into the bloodstream, Dr. Schmidt says.
Following a tick bite, diagnostic tests are used to identify the production of antibodies in the blood, says Phillip J. Baker, program officer of Lyme Disease and Anthrax Research Programs of the Division of Microbiology and Infectious Diseases at NIAID.
“It doesn’t always indicate active infection,” says Mr. Baker, who holds a doctorate in bacteriology.
The initial symptom of Lyme disease often takes the form of a red rash, called erythema migrans, that starts at the site of the bite and, over a period of days or weeks, expands. The rash, which can appear from three to 30 days after a bite, according to the ALDF, can resemble a bull’s eye with a red ring and a red center, or it can take other forms. The rash is usually not painful or itchy but can be warm to the touch, according to the ALDF Web site.
John Simmons of Great Falls and his doctor did not identify the three pink rashes on his body as evidence of Lyme.
Mr. Simmons, who figures he was bitten by a tick two summers ago when he landscaped his yard, thought he was having a reaction to over-the-counter medication he took for fever symptoms. The infection he received from an unknown tick bite spread to his heart, causing him to experience lightheadedness and an unsteady heartbeat. When he was about to
receive a pacemaker, an infectious disease specialist asked him a few questions and identified his condition as Lyme disease.
“That was the wildest experience,” Mr. Simmons says. “It’s a little black dot like a pinhead. I was disgusted with the idea.”
The rash associated with Lyme disease can be accompanied by other symptoms, including fever, muscle ache and headache, Dr. Schmidt says. A month or more later, symptoms can include joint pain, Bell’s palsy and a heart infection that disrupts the heart’s electrical conduction system and causes irregular heartbeats, she says.
“We treat with different antibiotics, depending on the stage,” Dr. Schmidt says.
Initial symptoms can be treated with oral antibiotics, but late Lyme disease usually requires four to six weeks of intravenous antibiotics, she says.
Late Lyme disease, which can occur a year after infection if not treated, can cause chronic arthritis, meningitis and encephalitis.
“It sets up what we call an autoimmune response in the body and triggers an inflammatory reaction,” says Dr. Robert Edelman, professor of medicine at the University of Maryland School of Medicine in Baltimore.
The bacterium shares similar surface antigens with some of the tissues in the human body, Mr. Baker says. The body produces an immune response to joint tissues in addition to the bacterium, he says.
“That’s why it’s difficult to make vaccines against some things. They resemble the body too closely,” he says.
Even if treated, a person reinfected with the Borrelia burgdorferi bacterium can get Lyme disease a second time, according to the NIAID Web site.