How is Head Lice Spread

Head lice impact as many as 6 million to 12 million people around the world regardless of race, age, economic status or personal hygiene. Head lice (Pediculus capitis) spread by direct contact with the hair of the infected person. Human lice infestation is known as pediculosis.

Identification

• A head louse is a small, wingless insect with a grayish-white body about 1/6 inch long. Lice have limited crawling ability and cannot fly or hop. They affix egg cases or nits to the host's scalp at the back of the neck and behind the ears where the hatching temperature is favorable. Lice use sucking mouth parts to feed on blood several times daily. They inject saliva that causes itching and irritation. Head lice cannot survive more than two or three days off their host. Nits can survive up to 14 days without a host.

Impact

• Symptoms of head lice include irritability and itching as an allergic reaction to the bite. Although lice are not known to spread disease, excessive scratching can increase the risk of secondary skin infection, according to the Centers for Disease Control and Prevention.

Spreading

• Direct contact with infested hair is the most common way to spread lice. Contact with personal objects including sharing of hats, hair ribbons, combs, hair brushes, sports equipment and towels can also spread lice to a lesser extent. Lice have difficulty gripping slippery or smooth materials.

  Children between 3 and 12 years of age are more prone to lice that can spread in group settings such as schools, childcare centers and sports activities. Domestic animals cannot spread head lice.