Check her whole head, with particular attention to the areas behind the ears and at the nape of the neck. Lice are tiny, flat insects about 1-2 mm long and greyish brown in colour. They blood feed on the human scalp. Nits are the tiny eggs, which may look somewhat like dandruff to you. They are half the size of a pinhead, tan, brown or silvery in colour and oval in shape.
Head lice do indeed occur world-wide .
They only live and feed and reproduce on the human scalp. They simply crawl head to head when people are in close proximity. Lice are a nuisance but not a health hazard.