Tick-Killing Tip: Dry Then Wash, Brief Dryer Spin Could Do It

Tip #1 on (Courtesy of TickEncounter Resource Center)
Tip #1 on (Courtesy of TickEncounter Resource Center. Note the tiny black tick in center foreground.)

It sounds so odd, like being told, "Put on your shoes, and then your socks." But indeed, one useful tip for killing the ticks that carry Lyme disease is to put the clothes you were wearing outside into the dryer for a few minutes before you wash them — the better to kill the ticks, you see.

How long exactly to dry them? Well, today's Boston Globe features a delightful story about a Braintree teenager, Jacqueline Flynn, who set out to find out, and whose preliminary research suggests that ticks can be killed in just five minutes of drying at low heat.

That discovery by the 16-year-old Braintree High School student has won top local science prizes and has caught the attention of scientists at the Centers for Disease Control and Prevention, the nation’s massive health watchdog.

As part of its tick prevention recommendations, CDC literature urges tumbling tick-infected clothing in a dryer on high heat for at least an hour as one way to eliminate the bloodsucking arachnids. But the agency had not studied the method further...

“This could have significant implications for Lyme disease prevention,’’ said Christina Nelson, an epidemiologist at the CDC’s office in Fort Collins, Colo., who became intrigued by the teenager’s finding. “If it is true that five minutes in a dryer kills ticks vs. a full hour, that is a lot easier for people, and that could also spark further investigations.”

With tick season, and thus Lyme disease season, soon upon us, however, we wouldn't want to draw half-cooked conclusions and under-dessicate any of the little buggers. So I checked in with tick expert Tom Mather of the University of Rhode Island and its TickEncounter Resource Center.

He confirmed that a fairly quick spin in the dryer can kill nymphal deer ticks that carry Lyme disease, as the TickEncounter Resource Center has been recommending:

Most ticks are VERY sensitive to dryness. The very first action to take after working in the yard is to strip clothing off and throw it in the dryer. Deer ticks are most susceptible, while American dog ticks, Lone Star ticks and other Amblyomma species are more robust. To be sure that each species achieves fatal crispiness, leave clothes in the dryer on high for 15 minutes.

In our study, gas dryers got hotter than electric dryers, so you might want to add 5 minutes if you own an electric dryer. Believe it or not, ticks were not killed by washing, even in hot water. Clothing just left in the hamper or on the floor may put the next person to touch it at risk. Dry first - then wash.

And Prof. Mather added more research details in an email:

We showed that nymphal blacklegged ticks [a.k.a. deer ticks] were the most sensitive to dessication (easiest to kill in dryer) of all tested, followed by adult deer ticks, nymphal Lone Star ticks, and then adult Lone Star ticks and Am. dog ticks. We found that gas dryers ran a little hotter and that as little as 5 minutes was sufficient to kill the deer ticks but that to kill all of the Lone Stars and dog ticks, 10 minutes was required. For good measure, 10 minutes in the electric dryer for all was recommended (but probably overkill). We had temperature records as well. Ours were field-collected ticks. We applaud Jacqueline’s innovation; her observation is consistent with our findings...

It's never too early to start thinking about measures to prevent Lyme disease, which is now endemic across Massachusetts. Check out other helpful TickSmart tips here.

This program aired on April 1, 2013. The audio for this program is not available.

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Carey Goldberg Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.



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