Sudden rat death - Fits

Question
Hi,
I have two female rats, both aged roughly 6 months old. This morning
i awoke to find one of my ratties sitting, curled on the floor
of her cage with little movement. We were unable to take
her to the vet immediately and so i sat with her wrapped in a
blanket until we were to leave for the appointment. while i was holding her she suffered a few sudden fits or spasms.she was breathing slowly and her heartbeat was faint, but every now and then she would take in a big wheezing breath - i could tell she was fighting whatever was wrong.
She was fine the night before when i checked, and her cagemate
seems to be fine also. She died just over an hour after i found her.
Are you able to suggest what might have been wrong with her?

Answer
I am so sorry for your loss.  She was too young to die thats for sure.

It sounds like your rat died from respiratory distress, probably from an acute case of pneumonia caused by the Strep bacteria.  This comes on very suddenly and can kill within 12 hours.  
Were her fits like panic attacks or just twitches?

Again I am very sorry for your loss.