Surge in deer ticks put East Coast hikers at risk says Penn State entomologist
Penn State release
November 30, 2005
University Park, Pa. — Every year it seems the tick identification laboratory in Penn State’s entomology department receives more submissions from residents around the state than the year before. But Steven Jacobs, the extension entomologist who oversees the lab, said this year is different.
This fall, there’s been an apparent explosion in Pennsylvania’s population of deer ticks, the eight-legged arthropods known as the primary vector of Lyme disease. And that concerns Jacobs, as thousands of hunters prepare to head to the woods for deer season.
“This year, the lab has received over 35 percent more deer ticks — from more locations — than last year at the same time,” he said. “Many of these submissions are coming from areas along the Allegheny plateau — the Appalachian corridor that runs from Somerset and Bedford counties in the southwest to Wayne and Pike counties in the northeast. But surprisingly, we’ve received submissions of deer ticks found in municipal parks in urbanized areas, which is almost unheard of. We’ve also heard anecdotally that people are encountering more ticks in the woods.”
The uptick in deer ticks was unexpected after a hot, dry summer that seemed to keep tick populations in check, Jacobs said. Although some experts say that higher tick numbers are not unusual during a warm autumn, Jacobs said the reason for the significant increase is unknown.
In general, deer ticks have become more abundant across the state in recent years. Previously limited mostly to hot spots in the northcentral mountains and the southeast and on the Presque Isle peninsula in Erie, the ticks have spread to virtually every region of the state.
The deer ticks being found this fall are adults, as opposed to the nymphs that most often are encountered in the spring and summer. “In October and November, female ticks are ‘questing,’ or looking for a host,” Jacobs explained. “Typically by this time, they have fed and dropped off their hosts. But this year, they still appear to be questing, putting hunters and others at greater risk.”
Jacobs warned that without snow cover, these adult ticks can be active in temperatures as low as 28 degrees F. “You could be hunting in a place, sitting on a log — which actually would be one of the worst places to be — as the sun comes up and the temperature rises,” Jacobs warned. “It could be 30 degrees, and ticks could crawl off that log or from vegetation surrounding you. You may not think that ticks would be a problem when it’s so cold, but in fact they can be active.”
Hunters also could encounter ticks on any deer they harvest. “Male ticks will stay with deer over the winter,” said Jacobs. “It becomes sort of a ‘singles bar’ for ticks, with the males waiting for the off-chance of finding a female hanging around to reproduce with.
Traditionally, the passenger pigeon has been held as one of the more beloved animal species to fall prey to humankind’s often relentless expansion into and disregard for the natural world and its creatures. Once abundant, the bird experienced a rapid decline in the late 1800s, due almost entirely to rampant hunting, and the last passenger pigeon died in 1914. In light of new findings however, this image of a naturally plentiful species laid to waste by man is now being tested. Evidence collected over the past few years from a significant number of Native American archeological sites is beginning to upset long-accepted beliefs about one of the most famous extinct species in modern history.
It might be difficult to imagine how the loss of a particular bird species can cause an outbreak of human disease, but the Stanford University research team behind the study offered an equally compelling and convincing yet disturbing example. Team researcher Gretchen Daily cited the example of the oft-discussed passenger pigeon, revealing that its extinction is believed to have exacerbated the proliferation of Lyme’s disease. When the birds existed in large numbers, the acorns on which they subsisted would have been too scarce to support the large populations of deer mice that flourish today. These rodents are the main reservoir of Lyme’s disease, and the acorns make up a significant part of their diet.
“If you find crawling arthropods on the stomach or between the hind legs of a deer, those are likely to be biting flies or ‘deer keds,’ which drop their wings and attach to feed,” he continued. “But if you find what appear to be ticks around the ears, eyes and neck, there’s a good chance they’re deer ticks, which then could crawl onto people or pets.”
Jacobs said the best line of defense against ticks may be insect repellent, although he acknowledges that many hunters resist using repellents containing DEET because the scent can be smelled by deer. “As an alternative, products containing permethrin have very little odor and are effective for about 24 hours, but they must be sprayed on clothing the night before because they have to dry first, and they shouldn’t be applied to the skin,” said Jacobs.
Because ticks can get between layers of clothing, Jacobs advises hunters to remove their hunting attire outdoors to avoid bringing ticks into the house. “Keep in mind, we’ve learned that washing clothes in warm water and detergent doesn’t kill all these ticks,” he said. “The only sure way to get rid of them is to dry clothes on high heat for a long cycle time.”
To learn more about ticks and tick-borne diseases, http://www.ento.psu.edu/extension/factsheets/common_ticks.htm online.
This article is a modified news release from Penn State. The original version appears at Penn State entomologist: Deer tick uptick puts hunters, hikers at risk