How are head lice spread?
Head lice are only caught by prolonged head-to-head contact of at least 30 seconds.
They are extremely unlikely to be caught by sharing hats and hairbrushes, since the lice cannot survive away from the warmth of the human head. Their tight grip on the hair with their 'claws' ensures they do not accidentally fall off the head. Any lice found on hats, brushes or pillowcases are either dead or dying and are too weak to crawl back onto the head.
They cannot be spread by pets as they only live on the human head. Pets do not sweat through their coat so it's not humid enough for lice to thrive.
Anyone can catch head lice but children aged 4-12 are more prone to catching them. This is because they touch heads frequently during play. For the same reason, girls tend to get them more than boys.
Tying back long hair does not really help prevent the spread of head lice since the lice rarely venture far from the warmth of the scalp.
It's also not true that short hair will keep lice at bay since they need only 3mm of hair to live on.