Aug. 24, 2000 -- The start of the school year can mean more than just back-to-school shopping trips and first-day-of-class jitters; for many children, it also means creepy, crawly head lice. Even hearing the words makes most people wrinkle their noses in disgust. But are the strict measures taken against head lice -- such as the so-called "No Nits" policy that bars children with even one louse egg from attending school -- warranted, or are they overkill?

For one scientist from the Harvard School of Public Health, society has definitely gone overboard, over-diagnosing, over-treating, and over-worrying about a minor nuisance that doesn't even qualify as a public health issue.

"We are dealing with head lice: They don't cause disease, they don't transmit anything, and we think they are much less contagious than people believe," says Richard Pollack, PhD, an instructor of immunology and infectious diseases.

Pollack and his team of researchers recently published a study in the Pediatric Infectious Disease Journal that showed that in about 40% of cases, head lice are incorrectly diagnosed, leading to unnecessary treatments and unnecessary absences from school.

Pollack invited people who visited a web site that provides information on head lice to submit specimens of items that they considered to be lice or nits. The researchers examined the samples under a microscope within two days of receiving them. Each sample was identified by the species of louse and its life stage (egg, nymph, or adult). A person was considered infected if their sample included at least one adult or nymph louse, or a louse egg capable of hatching.

The researchers received more than 600 samples, each containing from one to 100 or more objects. Lice or their eggs were found in 60% of the samples; other critters, such as beetles, mites, and bedbugs, were found in 5%. The rest contained other debris, including dandruff, scabs, fibers, dirt, and knotted hair.

Slightly more than half of the samples that actually did contain lice or nits had a living louse or egg capable of hatching (indicating an active infestation); the other half were either hatched eggs or dead eggs.