As if head lice are not enough bad news, so-called "super lice" have emerged and started terrorizing parents and their children.

The regular head louse common among many school-aged children have evolved and turned resistant to pyrethroids, neurotoxins incorporated in medicated lice shampoos. They have become more and more difficult to annihilate just like widespread antibiotic-resistant bacteria.

Recent research warned that lice are 99 percent resistant to typical over-the-counter treatments found in 25 states in the United States today.

Identified by experts are three genetic mutations affecting the nervous system of the resistant parasites, which have spread in North America, according to Southern Illinois University assistant professor Kyong Yoon, Ph.D.

Yoon warned that super lice have a greater chance of surviving the chemicals in lice-fighting products, dubbing it as "natural selection."

According to studies, resistance of lice to topical insecticides has been the most common cause why treatment fails in the past decade. Since the early 1990s, pyrethroids have been overused resulting in knockdown resistance, which means that lice no longer wriggle their legs and die shortly after exposure. Yoon said that the resistance now "is almost at saturation levels."

A 2012 Canadian study that analyzed head lice from 92 subjects showed that 97 percent of the head lice exhibited mutations. While this and similar research did not say that pyrethroids can no longer kill lice, the mutations raise the risk for lice recurrence.

The U.S. Centers for Disease Control and Prevention (CDC) also found that kids exposed to large amounts of pyrethroids on their skin may experience itching, numbness, burning, tingling, or a warm sensation.

Worsening the problem is the social stigma attached to having lice, which forces many parents to fight the parasite in silence. According to biologist and natural lice-treatment product owner Marnie Murray, 25 percent of kids between ages 3 and 11 have head lice but with great hesitation to admit it.

"It is part of being human," she said of getting lice, also warning against repeating chemical treatments more than twice and leaving the medication on for an hour when directions specify only 10 minutes.

Wet-combing is one of the time-tested ways to clear up head lice without the use of insecticides. It involves the use of a nit comb and combing through small centimeter-wide hair sections one at a time. While time-consuming, wet-combing does not need to be done daily.

Watch below the report of scientists on treatment-resistant lice across the U.S.


Photo: Gilles San Martin | Flickr

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