URI entomologist says deer tick numbers up significantly, increasing risk of contracting Lyme disease

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KINGSTON, R.I. – July 6, 2012 – Now that the peak of summer outdoor activities are starting, a University of Rhode Island entomologist warns that deer tick numbers in Rhode Island are up 80 percent over 2011 levels and 142 percent above the previous 5-year average, meaning that the risk of contracting Lyme disease or other tick-borne diseases is especially high.

Thomas Mather, director of the URI Center for Vector-Borne Disease and the TickEncounter Resource Center, reports that his tick surveillance team has completed the first round of tick sampling at all 60 of the sites monitored for the past 18 years, and he is alarmed at this year’s increases.

For example, at one site in East Greenwich where sample counts are typically 14-20 nymphal deer ticks in 90 samples, this year the team collected 187 ticks. Sites in Bristol, Tiverton and Johnston, among other places, also saw triple digit percentage increases compared to last year. A second round of surveillance has already begun, and so far, the counts are coming in higher than in round one.

“Tick abundance is really high this year, and that means that people need to get TickSmart,” said Mather, referring to TickEncounter’s newest public education and call to action campaign for Rhode Island. “So many people either believe they already know the best way to prevent tick bites, or they don’t believe ticks will bite them. The tick bite protection practices used by most folks are just not appropriate or enough for preventing bites from nymphal stage deer ticks. “

Mather said that unlike other models used to predict tick encounter and Lyme disease risk, his research has shown that nymphal deer tick abundance and disease rates are determined by relative humidity levels in June. Higher humidity means greater tick survival, more tick encounters and more disease. Episodes of low humidity, even as brief as 8-10 hours, causes nymphal deer ticks to dry out and die earlier in the tick season.

“We’ve had perfect tick weather during May and June, which means that few ticks were killed off, and that’s keeping the numbers high throughout the region for now,” said Mather, who also serves as a member of Governor Patrick’s Commission on Lyme Disease in Massachusetts.

To be TickSmart, Mather says residents and visitors need to pay closer attention to the type of tick they come in contact with. “Not every type of tick will make you sick,” he said. “Right now people are encountering tiny poppy seed-sized deer ticks that will make you sick and large American dog ticks that rarely transmit disease in Rhode Island. In the fall, the larger ticks people and pets encounter are adult deer ticks, not dog ticks, so disease risk is high then, too.”

Other TickSmart tips include doing daily tick checks, “especially at bath time when you’re already naked,” he said, and always wearing tick repellent. Mather advises that it’s important to know what to look for in your daily tick check, and the most likely places to look — ticks the size of poppy seeds biting below the belt.

“Wearing the best tick repellent is as easy as getting dressed in the morning,” Mather said, referring to clothing treated with a repellent containing Permethrin.

The TickEncounter website, www.tickencounter.org, has rapidly become one of the nation’s premier tick bite protection resources and provides a growing catalog of TickSmart tools, including a popular, interactive tick identification chart, shower cards for prompting daily tick checks, tick encounter risk maps, and many other TickSmart strategies for protecting yourself, your pets and your yard from ticks.

Mather will participate in a press conference with Senator Jack Reed and Lyme disease officials from the Centers for Disease Control, the National Institutes of Health, and the Rhode Island Department of Health on Monday, July 9 at 11:00 at the Department of Health auditorium in Providence. At the event, Reed will call for a national strategy to combat the disease and expand federal research efforts to increase surveillance and prevention.