I had my cat for over two years now. I got her from the local SPCA. She never went outside until now. Now every time someone opens the door, she runs out of the house, and stays out for up two days. When I try to catch her to bring her in, she runs away from me. She is fixed and has her claws, but I am wondering what is with the sudden fascination with the outside. I don't want her picking up fleas or getting hurt. Is there something I can get to keep her in the house or should I just let her be?