Tick explosion is the price of mild weather
Winter’s warm temperatures have yielded an unusually robust bounty of springtime ticks that have attached themselves to pets and people in Massachusetts. But the same warm, dry weather that fueled an explosion of ticks may ultimately stifle survival of young ticks known as nymphs that are most prone to spread disease.
“Deer ticks are exquisitely sensitive to drying out,’’ said Richard Pollack, a tick researcher at Harvard’s School of Public Health. “This can shorten their survival, which could be good for people, but not so good for deer ticks.’’
There is some disagreement among specialists about the reasons for the bumper crop of ticks. Maybe, some scientists contend, it is because of a surge in rodents last year. Ticks feed on rodents, and because there was a proliferation of white-footed mice last year, that gave ticks more sustenance and, thus, allowed for more ticks.
This much, most specialists agree on: Adult ticks generally go dormant in the winter, nestled under leaves and snow, and then wake up in spring, hungry and looking for a blood meal. But seemingly confused by the balmy winter temperatures, the ticks never seemed to take a break and latched on to prey in large numbers the past several months.
Ticks can spread illness to people. They carry not only Lyme disease but germs for two other illnesses becoming more common in Massachusetts: babesia and anaplasmosis, which usually produce fever, chills, and muscle aches, and are generally easily treatable.
At Angell Animal Medical Center in Boston, doctors are seeing a dramatic rise in tick-infested dogs. The center reported performing 1,445 tests for tick-borne illnesses in the first three months of this year compared with 511 in the same period last year.
Craig Hollingsworth, an insect specialist at the University of Massachusetts at Amherst Extension Center, tests ticks sent in from doctors, hospitals, and residents across the state to determine if they are carrying Lyme or other diseases. Hollingsworth said his lab has received six times as many samples in late March and early April, compared with a similar period the past two years.
“That’s because we had record numbers of adult deer ticks from last fall going into the winter,’’ Hollingsworth said.
The adult deer ticks that are latching on to people and pets now are only responsible for transmitting about 15 percent of reported infections of Lyme disease. It is he younger nymphs that typically transmit illnesses in May, June, and July.
It is not that adult deer ticks carry fewer germs; it is that they are larger than young nymph ticks - think a sesame seed compared to a poppy seed - so they are easier to spot and remove before they spit enough bacteria into the skin to cause infection.
Ticks generally have to be latched onto a person for 24 to 36 hours to transmit enough germs to cause illness, said Dr. Alfred DeMaria, the state’s top disease tracker. Usually by then, the ticks are fully engorged and more resemble a grayish, squishy marble.
In recent years, Massachusetts has averaged about 2,000 confirmed cases of Lyme disease annually. The condition is heralded by fatigue, chills, fever, headache, muscle and joint aches, and, in many cases, a telltale bull’s-eye rash.
The best way to protect against tick bites is to wear long sleeves and pants, tucked into socks, when walking in grass and woods, but DeMaria said that is not generally practical in the summer when it is hot outside. He also recommends wearing insect repellent with DEET, and after coming inside, a thorough check of areas of your body where ticks typically love to hide - arm pits, the groin, hairline, and behind the ears.