I got a rat during the summer who appeared to have a pretty severe URI, gasping and wheezing really bad. I intended to take him to the vet as soon as I had the money (2 weeks), but by that time his problems had vanished, so I watched him carefully for the next little while and he was fine, has been ever since. What do you guys think of this? I mean, for that first week it was so bad that I didn't think he'd even make it. How could that have gone away on its own?