Lice or nits are prone to the kids especially when they have close contacts with the one who has it. But this wonders me, where did it really come from. Is it the same with other insects that just came from nowhere and no specifics legends about it? I tried to research it in goggle and this is what I found:
Head lice are an infestation with a parasitic known as Pediculus humanus capitis, so it evolved from primate hair to human hair millions years ago. And the first one who has it was a mummy buried in Northeast Brazil.
So kids since it is summer now, proper hygiene is a must as they are prone when it is too humid or too hot although they do not came from the heat of the sun but with the one whom you close contact with. If you have it, treat it immediately so it will not spread. And disinfect all the things in the house.