As students prepare for those first school bells in the next week or two, researchers are warning parents about a pest that may await them: super lice.

Scientists who study lice populations across the country have reported that the bugs found in at least 29 states have developed into creatures quite resistant to common over-the-counter treatments. The researchers reported those findings to the American Chemical Society this week. Kyong Yoon, Ph.D., a Southern Illinois University researcher, was among those who uncovered the findings.

"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," Yoon was quoted in a media release as saying. >>Related: 5 Tips To Fight 'Super Lice' As Kids Go Back To School

In 25 states -- including Arizona, California, the Carolinas, Connecticut, Florida, Georgia, Illinois, Maine, Massachusetts, Texas and Virginia, lice have what Yoon calls "knock-down resistant mutations," or genetic alterations that render them immune to over-the-counter permethrin treatments. Four states - New Jersey, New Mexico, New York and Oregon - have lice that have developed partial resistance to treatments.

Pyrethoids are a type of insecticide that is commonly used to help control mosquitoes and other insects, such as lice. Yoon ultimately found that some lice populations were developing mutations that enabled them to survive exposure to the insecticides commonly used to treat children and adults who suffer from infestations.

A Chicago hairdresser already has seen these "super lice" up close — and what she sees isn't pretty.

Renee Wilson, manager of Hair Fairies, told CBS Chicago that parents are "upset" and "stressed out" because the over-the counter treatments don't work. "They just want to give up," Wilson said. ""If that bug is crawling around the head and then someone is giving hugs, sharing hairbrushes, or by that person, that bug can transfer like that."