How do head lice spread from person to person?
Head lice move by crawling; they cannot hop or fly. Anyone who comes in head-to-head contact with someone who already has head lice is at greatest risk. Spread by contact with clothing (such as hats, scarves, coats) or other personal items (such as combs, brushes, or towels) used by an infested person is uncommon.
Can head lice be spread by sharing sports helmets or headphones? Head lice are spread most commonly by direct contact with the hair of an infested person. Spread by contact with inanimate objects and personal belongings may occur but is very uncommon. Head lice feet are specially adapted for holding onto human hair.
- Be sure the hair is dry when the medicine goes on. The way these products work is to temporarily paralyze the muscles the lice need to breathe. Ultimately they die from lack of oxygen. But when lice are wet they have a self-protective mechanism and can hold their breath for 30 minutes or more!
- No hair is immune to head lice. There is a misconception that African American hair, because it is coarse, is resistant to head lice. Lice do not care whether hair is smooth or coarse, thin or thick. Lice affix themselves to a strand of hair as a way to get up to the scalp to access their food supply: human blood.
- The nits are not contagious; it is the lice bug that is contagious because it travels from head to head. Girls with long hair should wear their hair up and off their shoulders if possible so it is less likely to come in contact with someone else's hair or clothing.
Head lice can survive on a human host for approximately 30 days. They generally cannot survive longer than 24 hours off the host. A female louse lays 3-5 eggs a day. The eggs hatch in 7-10 days and it takes another 7-10 day for the louse to mature and lay their own eggs.
- After that they can survive 6-48 hours away from a host. Head lice can not fly or jump. They crawl from place to place and must pull themselves through fibers or strands of hair. They can not crawl on hard smooth surfaces.
- Hair lice can pass from person to person when people share personal items, such as combs, towels, clothing, hats, and hairbrushes. Lice are not spread by dogs, cats, or other pets. Because hair lice cannot jump or fly, they crawl from one person to another, using their claws to grab onto hair.
- The clades of human head lice, named A, B, and C, have different geographic distribution and varying genetic characteristics. According to the Journal of Parasitology, Clade B head lice originated in North America, but migrated to farther reaches of the world, including Australia and Europe.
Updated: 17th October 2019