Planning a picnic this spring? Bug spray could be one of the most important items to pack.
With a mild winter and a warmer, early spring, researchers predict 2012 will likely be a bad year for ticks, perhaps leading to a higher incidence of Lyme disease infection.
Paul Curtis, professor of natural resources and extension wildlife specialist at Cornell University, offers that prediction. If it proves accurate, the increase would be part of a continuing trend. Lyme disease cases in Suffolk County have increased from 234 in 2007 to 609 in 2010, according to the Suffolk health department.
Lyme disease is a flu-like illness caused by the black-legged tick, commonly known as the deer tick — only one of three types of ticks found in the area. The East End is also home to the lone star tick and the common American dog tick.
Dr. Lawrence Schiff of Eastern Long Island Hospital, who specializes in internal and emergency medicine, said the pathogen causing Lyme is transferred when a deer tick has been attached to a host for longer than 24 hours. The preferred treatment is the antibiotic Doxycycline. Dr. Schiff said it’s possible for someone who has contracted Lyme very recently to have tests come back negative.
A repeat test should be done, he said, if the person continues to experience hallmark symptoms like fever, night sweats, achy joints and a rash at the site of the bite. According to Cornell Cooperative Extension entomologist Dr. Dan Gilrein, Lyme disease can be spread by the difficult-to-spot younger nymphal ticks, which are no larger than a sesame seed, and so small that they’re easy to miss and hard to feel when they crawl on or bite a human host.
Nymphs are a significant cause for concern, Dr. Gilrein said, because many mature ticks should already have found hosts in the woods by now. With the unusually mild winter there’s a higher probability of that mature deer ticks are active on any day above 40 degrees.
Nymphal ticks, on the other hand, are most active between May and June, he said, and therefore more likely to come in contact with humans spending time outside during those months.
Dr. Gilrein said deer ticks can also carry pathogens causing other worrisome illnesses, such as Babesiosis and Anaplasmosis.
“They are both also flu-like illnesses,” he said. “From what I understand, people who have had either are usually treated with antibiotics and recover completely.”
Dr. Gilrein said it’s likely lone star tick numbers will also rise this summer. Lone stars do not carry Lyme disease, but can carry Ehrlichiosis, another flu-like illness. The bite of the lone star tick is much more noticeable than the deer tick’s and generally causes an itchier, more annoying rash. Dr. Gilrein said the adult female lone star tick has a white spot on the back and is found not only in damper, shady areas like the deer tick, but also in open fields and other sunny spots.
“We had what appeared to be a serious decline in lone star ticks due to weather conditions in 2010, but while sampling ticks, we saw the larval population was beginning to rise,” Dr. Gilrein said.
“This past year’s counts showed the numbers of both nymphal and larval lone star ticks had jumped quite a bit,” he said. “The larval ticks from last year are going to be adults this year, so people are going to start noticing them more.”
People can protect themselves from the pests by using repellents, pulling high socks up over pants legs and checking frequently for ticks after being outside.
High populations of deer and mice contribute to higher populations of ticks, said Mike Scheibel, a biologist at the Mashomack Nature Preserve on Shelter Island. Mr. Scheibel helped with Cornell’s four-year study of the efficacy of the 4-poster study, designed to help curb tick populations.
“The device has now been registered for use in Suffolk and Nassau counties,” Mr. Scheibel said. “Shelter Island is deploying as many as they can afford to,” which he said should be 15 units this spring and summer.
A 4-poster device is a corn-filled feeder with paint rollers containing the insecticide Permethrin at each of its four corners. When deer feed from the trough, the insecticide is then rubbed onto their neck and ears.
“We found the 4-poster devices worked as expected,” Mr. Gilrein said. He added the devices did not increase car collisions with deer or significantly change the deer’s moving patterns as some had feared.
“Deer aren’t diverging from their normal habits to feed from the 4-poster devices,” he said. “They pretty much have a home range and stay where they’re comfortable.”
The numbers of lone star tick nymphs reported in 15 minutes of sampling in 4-poster areas on Shelter Island during the study revealed both the efficacy of the devices as well as the increasing population of the pests that should be noticed this summer.
In 2008, 468 lone star nymphs were recorded in the 4-poster areas on Shelter Island with only 173 in 2009 and just 11 in 2010.
That number increased to 40 last year.
Dr. Gilrein will give a lecture to the public on both ticks and the 4-poster study at 8 p.m. on Thursday, April 12, in the auditorium at Peconic Landing in Greenport. Call 477-3800, ext. 379, and leave your name and the name and date of the lecture to ensure adequate seating.
Dr. Scott Campbell, the lab director for arthropod-borne diseases for the Suffolk County Health Department, said it’s still too early to tell whether there will be an increase in Lyme disease cases this summer.
“A high population on Shelter Island may not be a true representation of what happens,” he said. “It may be true there, but may not be true everywhere. It’s site-specific.”
Many factors affect tick population and infection rates, said Dr. Campbell, who believes theories that point to any one factor to predict the amount of Lyme cases may not be entirely accurate. He cited the theory that a year’s acorn yield can be used to predict the amount of Lyme cases.
“It says a large acorn year means more food for mice and therefore a higher number of mice infected with the pathogen, but there’s more to the story,” he said. “When ticks quest for hosts, they’ll feed on deer, birds and other rodents, not just mice.
“I don’t think there’s any one factor that contributes to the amount of Lyme cases,” Dr. Campbell added. “That would be putting all your acorns in one basket.”