Question about Werewolves

[Mindy, a.k.a. CLH]

No: HPFGUIDX 24042

I am not very very familiar with all the magical creatures and misfits.
So can someone please explain to me how one becomes a werewolf? And how
come there is no cure for werewolfs? If werewolves only become wolves
once a month, and are normal and even nice ppl like Lupin was for th rest
of the month, why don't 'we' know of any other werewolves besides Lupin?