Can a healthy mouse chirp?

Question
Hi :)  I have three female mice, Luna, Moo and Nimue.  I've had them since February.  They are not my first mice, but I am learning so much more this time around.  My last mouse passed away five years ago, and looking back, I could and should have done more with/for her. :(

Luna is the tamest of my mice. I can handle her well, but she never sits still on me for long.  She wants to run around and explore, come back on her own terms.  Note:  I play with them in my bathroom with all possible escape routes blocked.  They can't get under doors, into vents, nothing.  A few weeks ago, Luna started chirping.  Not wheezing, or coughing, but chirping.  She only does it when she's excited, like during or right after play time, or when she sees me after napping awhile.  I have a short video of it if you'd like to see.

I belong to a forum, a well known one, and several of the members there insist she has a URI.  Absolutely no other symptoms, her sisters have no symptoms and I haven't heard them chirp. I was told there, and I've seen elsewhere, that they should never make this sound unless they're ill.  I have also heard/read that some do indeed chirp, as if "talking".  You honestly more years of experience than these other people on the forum have even been alive.  I would like your input.

Answer
Dear Frankie,

You know what? it's a hard question. I am very sure that when I was growing up and taking care of my mice by the seat of my pants, many of the times when I thought a mouse had an adorable way of talking, it was a URI and the poor things either got better on their own, chirped their whole lives, or died from it without me knowing why.  : (((

I do know that most of the time, even when you think it isn't, it is a URI. But I also think there are just chirpy mice. If it never happens when she isn't happy, it is possible she is just talking.

Since I have had access to antibiotics and understood mouse wellness, I have not had a noisy mouse who wasn't cured with antibiotics. This is why I can't be sure. But I am pretty sure I had healthy chirpers before that.

You should know that it is entirely possible for one mouse in a cage to have symptoms of a URI. Either the other mice didn't catch it, or they aren't showing symptoms. Mice almost always have a low grade bacterial infection called myco, which only flares up under specific conditions-- things which lower her immune response. Some of these factors are any kind of stress, other illness, age, mites, temperature fluctuations, and of course, exposure to other mice with a stronger case of myco. But they don't always have a problem even when some of these factors are present, so it would be entirely possible that Luna could be ill and her cage mates completely healthy.

I would pay super, super close attention that it only happens when it makes sense it would, if she were happy. Even a URI would sound worse with excitement, because she would be breathing harder. I'm not going to say you should stress her out, to see if she can be excited (not positive) but not happy, to see if she chirps, but that is what to watch for. Or if she chirps in the nest.

The test would of course be to try antibiotics and see if the chirping goes away.

What I would do, myself, is to get the fish tetracycline that I recommend for URIs and not to give the initial dose, but just put it in the water. A full capsule for a standard hamster water bottle (10-12 oz). It is fine that the other mice would drink it. Shake it really well, cover it with tin foil, and change it every 2-3 days for ten days. If nothing changes, don't worry. If it stops, great; if it doesn't change, great; but if it becomes less but doesn't stop, she needs an oral dose of tetracycline, or another antibiotic, to get fully well.

That would rest my mind if it were my mouse. Of course it isn't a 100% guarantee, since tetracycline is a low grade antibiotic, but it is very likely to help if it is just a flareup of myco.

If you decide to do this, or if things change, do write back to let me know.

squeaks n giggles,

Natasha