Rat cant squeak/ hissing

Question
Hi, I have a fifteen month old rat and she doesn't seem to be able to squeak or at least not very well. I don't know if I remeber her actually squeaking before, but lately I noticed that she seems to be trying to squeak but can't. It kinda sounds like when you try to make a high pitched noise but can't, kinda that whooshing out air noise. Sometimes it breaks into a squeak at the end. I don't know if this just a normal rat hissing noise and she has just taken to hissing instead of squeaking. Or if it is something I should be concerned about and take her to the vet. And if it is something I should drag her to the vet for, what do you think it is in your opinion? (Maybe a side effect of myco or resp infection?) Also how it should possibly be treated (baytril?) Just so that I can be informed as possible c:. Anywho thanks for glancing over this!
-Sam

Answer
Hi Sam,
This does sound like it might be a symptom of a respiratory infection. What is her breathing like?  Normal breathing in a rat should be barely noticeable. Is she breathing hard?  You'll find an article called Respiratory Disease on my website at www.ratfanclub.org on the Rat Info page that would be good for you to read.
Deb