All three cause considerable skin irritation as they feed on human blood or crawl on the body. Typhus, impetigo, trench fever and relapsing fever have all been transmitted by body and head lice.
Human lice can establish and maintain themselves only on humans.
A louse cannot hop or jump. They can, however, crawl fast. They are usually transmitted only through close personal contact. They are less frequently transmitted through the sharing of personal articles or toilet seats. For head lice, this includes combs, brushes and other grooming aids, hats, headbands, helmets, caps, headrests, wigs, curlers or other headgear, especially when these items are stored in shared lockers.