Things you may not know about head lice (Pediculus Capitis) and why they are difficult to remove from your hair.  

Normally head lice infest a new host only by close contact with another individual, who already has head lice. The lice do not jump or fly and hence direct head to head contact is necessary for passing on the lice, such as may happen among children in social situations at play or at school and in parent-child interactions. Humans cannot pick up head lice from dogs or cats.