The words “head lice” can stir fear in parents everywhere. Head lice are misunderstood, yet very successful, human parasites that have been around for thousands of years. They are not a public health crisis, as some would believe, and they do not cause disease.

Common myths about head lice abound, and even pediatricians, school nurses and the Centers for Disease Control (CDC) still offer conflicting, outdated information about the diagnosis and treatment of these parasites. The good news is that head lice are manageable and can be safely treated without pesticides. In fact, pesticides are no longer able to effectively kill lice and lice eggs, known as nits. Here are some other myth-busting facts:

Myth: Head lice jump from head to head.

Fact: Head lice have no hind legs and are not able to jump. Transmission takes place when lice crawl from one warm human scalp to another during direct head-to-head contact.

Myth: Itching is a sign of head lice.

Fact: Most people rarely itch when head lice are present. When feeding, the lice inject an anesthetic, an anticoagulant and saliva. After two to three months, some people develop an allergic skin reaction to these substances and experience itching, a rash on the back of the neck, or both.

Myth: We need to launder, vacuum and bag up stuffed animals when head lice are present.

Fact: Head lice are not found in bed linens, carpets, clothing or stuffed animals (as are body lice). Because head lice are sensitive to temperature, light and humidity, they avoid inanimate objects, preferring to move directly from one warm human host to the next.

Myth: School lice policies are uniform and effective.

Fact: School lice policies differ widely, from no policy at all to no-nit policies to requiring pesticide treatments. Nonit policies are difficult to enforce, and do not prevent the spread of lice in school-aged children. In fact, the CDC reports that both the American Association of Pediatrics and the National Association of School Nurses advocate the discontinuation of no-nit policies.

Myth: Pesticide lice shampoos effectively eradicate head lice.

Fact: A 2003 study revealed that head lice have developed resistance to the most commonly used pesticide in these shampoos, rendering them ineffective. The nits also remain viable after the use of pesticide shampoos, many of which contain neurotoxins.

Myth: Non-toxic treatments such as olive oil and combing are ineffective.

Fact: Effective head lice treatment involves the mechanical removal of the lice and eggs using a nit comb. Olive oil effectively kills lice and eggs by starving them of oxygen. Unless every last lice egg is removed from the hair, the head lice colony will begin again. Combing the hair with olive oil or conditioner and a good metal nit comb is an effective, pesticide-free way to eradicate a head lice colony.

Myth: Those with head lice are dirty.

Fact: Head lice thrive in clean hair and spotless homes. This erroneous stigma comes from confusing head lice with body lice, which did thrive in squalid conditions. In today’s American homes with indoor plumbing, body lice are nonexistent. Managing lice in families and communities requires accurate information and effective tools. Demystifying the stigma of head lice and learning how to use a good nit comb costs very little and keeps pesticides off kids and out of the environment.

Berit Pratt, RN, BSN, MPH, is founder of NitWits Intelligent Lice Treatment, in Cambridge. For more information, call 617-816-9487 or visit LiceInfo.net.