Just in time for the start of the traditional school year, a strain of drug-resistant head lice has spread into North Carolina.

Head lice of all kinds can spread quickly within a classroom, where children share combs and brushes, hats, headsets and earbuds. Even a hug with head contact gives the lice an opportunity to move from child to child.

As many as 12 million school-age kids, mostly between 3 and 11 years of age get lice each year.

The typical treatment is an over-the-counter shampoo containing insecticides called pyrethroids, but the new strain of lice appears to have developed a genetic resistance.

A low-cost treatment is to use a fine-toothed comb to pick out as many lice as possible from a child's head.

For those with longer hair, doctors recommend smothering the lice by massaging mayonnaise onto the scalp, blocking the lice and their eggs from getting air. Cover the head with a shower cap and leave the mayonnaise on overnight.

A doctor can also prescribe a treatment like Ovide for kids over the age of 6.