Shit it seems I require just a little more aversion therapy as I almost broke into a cold sweat and could feel that horrible saliva in the mouth thing before you puke feeling kicking off in my mouth as I read the above ....
In all seriousness though it is funny / weird how one becomes programmed to dislike / fear things as my BF is a small guy, scared of his own shadow and permanently worrying about whether things are "clean" or not and yet when it comes to rats as you say Smiles he too was brought up around rice rats and doesn't even take them under his notice and things I'm an absolute nut job for my deep fear of them. He tells he stories of how he and his family members went into barns and killed them etc without a second thought, personally I'm not so sure and think he's been watching too much TV as this is the guy who if a wasp flies into the kitchen nearly breaks the door through to exit the room, no matter whether it's open or not !
When I was very young ( like 3 or 4 year old) my family lived in the inner city and I've a notion that rats abounded there and I must have had a few run ins with them there that left a negative lasting impression, I actually caught rtheumatic back then which I believe comes from an unclean environment ( my mother was spotless btw so it's wasn't HER) and the doc explained that was probably something to do with rats so I put all those things down to my aversion to this day.
Thankfully as I said Bkk has diminished my irrational fears somewhat along with reading a book or two about self CBT training too I would add.