sick mousie

Question
i work at a large chain pet store. i recently brought home a mouse which was going to die if it stayed there and i thought actually it was going to die at my home but i just wanted to get it out of the store. anyway its been about 2-3 weeks and i still have the little mouse. he is smaller than his tank mates with no descended testicles and now i am thinking perhaps its a female. he seemed to get better then again is sneezing and a little rapid breathing. he is not nearly as bad as when i brough him home but i can still hear the teeth chattering a bit and little sneezes. i had a stash of antibioics. his breathing was so bad and he was panicking so i gave some prednisone liquid by mouth for a few days to help him breath. he is also on panamycin (tetracycline i think) i am concerned though if this is not going to go away cause i also have 5 rats and i read about something called SDA and Sendai? I am now terrified he might have this? his eyes are clear and he is eating and drinking now quite well. please help. i am quite alarmed. if he did have this wouldnt he have passed on by now?

Answer
It sounds like he or she had respiratory infections and not SDA. Is the sneezing and breathing getting better? I would personally keep him or her seperated from the others until she gets better. If she isn't improving within a few days take her to the vet for a check up to further see what's going on with him or her.