Lyme disease threat highest in warm weather

No bigger than poppy seeds, juvenile deer ticks are lying in wait in the underbrush, ready to catch a ride on unsuspecting hosts. Once again it’s the time of year when the disease-carrying parasites are most likely to pass potentially crippling Lyme disease to humans.

Spring is the “most high-risk time of the year” on the South Shore, as deer tick nymphs eat their way to adulthood, said David Simser, an entomologist with the Cape Cod Cooperative Extension.

Recent weather cycles have worsened the annual threat, said Dr. Alfred DeMaria, director of communicable diseases for the state Department of Public Health.

“The wet spring and sudden warm weather has suddenly triggered a lot of tick activity,” he said.

While tick bites may be painful, the diseases that come with them can be debilitating, even deadly. In addition to Lyme disease, ticks can transmit babesiosis (also known as Nantucket fever) and anaplasmosis (also known as ehrlichiosis). Both diseases are much more rare than Lyme disease on the South Shore, but they can be even more dangerous if left undiagnosed.

The threat of Lyme disease on the South Shore has gotten increasingly worse in recent years, said Dr. Bela Matyas, the state Department of Public Health’s medical director of epidemiology.

In 2001, there were 171 reported cases in Plymouth County and 94 reported cases in Norfolk County. The infection rates soared in subsequent years: Plymouth County had 232 reported cases in 2006; Norfolk County had 279.

Matyas said actual incidences of Lyme disease could be much more numerous, given that some cases go unreported.

Black-legged ticks, commonly known as deer ticks, transfer Lyme disease by burrowing into the skin of animals and humans and feeding on their blood. Almost 50 percent of adult ticks and 20 percent of nymphs are infectious, Simser said.

Karen Forschner, chairman of the board of directors of the Lyme Disease Foundation in Connecticut, said the “nymphs are so tiny that people just think they are scabs or a bump on the skin. So while less of (the nymphs) are infected, more people get Lyme disease from them.”

Ninety percent of the people who get Lyme disease do have symptoms beyond a rash, a fever, tiredness, and aches and pains, said Dr. Thomas Treadwell of MetroWest Medical Center in Framinghmam. But if left untreated, the disease can cause arthritis, memory loss and damage to the heart and nervous system.

“If you have an expanding rash over a period of days, have it checked,” Simser said. . “It is sometimes warm to the touch and might itch a little.”

Experts recommend using insect repellent, wearing light-colored clothing to make ticks easier to see, wearing long pants and tucking shirts into pants and pants into socks.

If a tick latches onto your skin, Matyas recommends taking tweezers and pulling it straight out, like removing a splinter.

Lindsey Parietti of Gatehouse News Service contributed to this report.

Don Conkey may be reached at dconkey@ledger.com.