A "cootie" is an informal name for which parasite?

I'd never heard "cootie" used as a reference to lice. Growing up, I knew of cooties as imaginary critters that were carried by the opposite sex: one reason little boys and girls wouldn't want to play together.

A nit picker is a person whose job it was to remove lice eggs, called nits, from someone's hair. This tedious task was performed by grasping each individual egg that was attached to a strand of hair by the thumb and index finger and sliding it down the shaft...one nit at a time. That is why the word "nitpicky" describes a person who concentrates on small and unimportant details especially to try and find fault with something.

When my niece was five years old she had lice in her hair so my sister took her to the beauty salon to get a permanent wave in her hair and the chemicals in it killed the lice.

Now I know! When as a kid my family moved to Michigan from out West, kids used to tell other kids "You got the cooties." and run away from them.

A cootie must be an American slang word. Never heard of it in Australia.

In To Kill a Mockingbird (the book) one crawls out of one of the Ewells’ hair, and the teacher freaks out. She called it a cootie I believe.

As a kid a cootie was the mark left on the foot from hookworm infestation, usually caught by walking barefoot in sheep or cattle pens. When I read the word in an American novel I couldn't figure out how the children got them on their heads. This explains it.

Laudy Miss Claudy, these days a nit comb and lyclear do the job