School is in session, which means there's an increased threat of head lice. Annually, approximately 6 to 12 million cases are reported among U.S. children 3 to 11 years old, according to the Centers of Disease Control and Prevention (CDC).
Now, scientific evidence reveals that parents might have even more reason to dread these pesky bugs. Researchers found that lice in at least 25 states have evolved and now show resistance to widely-used over-the-counter treatments. The findings were reported at the National Meeting & Exposition of the American Chemical Society.
Of the 109 populations tested, 104 contained high levels of gene mutations, which have been linked to the resistance of certain synthetic chemicals, called pyrethroids. The active ingredient in most over-the-counter lice treatments (permethrin) is a part of the pyrethroids family.
Caitlin St John is an Editorial Assistant for Parents.com who splits her time between New York City and her hometown on Long Island. Follow her on Twitter: @CAITYstjohn.