Health Officials: 'Super Lice' Not Detected In Michigan.... Yet

DETROIT (WWJ) - Health officials say "super lice" have been found in children in 25 states, but not in Michigan -- at least not yet.

Scientists report that lice populations in at least 25 states have developed resistance to over-the-counter treatments still widely recommended by doctors and schools.

"We are the first group to collect lice samples from a large number of populations across the U.S.," Kyong Yoon, Ph.D., said in a statement "What we found was that 104 out of the 109 lice populations we tested had high levels of gene mutations, which have been linked to resistance to pyrethroids."

Pyrethroids are a family of insecticides used widely indoors and outdoors to control mosquitoes and other insects. It includes permethrin, the active ingredient in some of the most common lice treatments sold at drug stores.

In the most recent study, Yoon gathered lice samples from 30 states with the help of a broad network of public health workers. Samples of lice with a trio of genetic mutations known collectively as KDR, which stands for "knock-down resistance," came from 25 states -- including California, Texas, Florida and Maine. Having all the mutations means these populations are the most resistant to pyrethroids. Samples from four states — New York, New Jersey, New Mexico and Oregon — had one, two or three mutations.

The only state with a population of lice still largely susceptible to the insecticide is Michigan. Why lice haven't developed resistance in the Great Lake State is still under investigation, Yoon said.

So, what's the solution to combating these super lice? Yoon said the bugs can still be controlled by using different chemicals, some of which are available only by prescription.

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But the situation also offers a cautionary tale. "If you use a chemical over and over, these little creatures will eventually develop resistance," Yoon said. "So we have to think before we use a treatment. The good news is head lice don't carry disease. They're more a nuisance than anything else."

Yoon presented his research at the National Meeting & Exposition of the American Chemical Society.