It could have been salmonellosis.  It's not common though.

Odd.

Did it seem fat? Anything that causes excessive swelling in the gut will eventually contribute to infection. Was it female? Pyometria is a risk too

I guess this is dependent on whether it was definitely the anus. I've seen pus come out of a lot of mouse vulvas for a variety of reasons at work. 

I'm not sure I'd associate green discharge with salmonella either? I'd be more inclined to think blood would have been present, but that would depend on the strain I suppose.

Honest question.............what did the discharge smell like?

You thinking pseudomonas, G? 

 Is that respitory? 

It can happen in all sorts of places, but it's often grren and smells really sweet...a bit like grape koolaid.

It's opportunistic and lives freely in the environment so it's a common secondary infection, and sometimes primary.

i diDNT SMELL THE DEAD MOUS E' S ASSHol e om g

the mouse was definitely male, by the by. definitely out of the anus, and it definitely seemed swollen...

Are you sure the swollen anus isn't just his privates? And did the stuff definitely not look like diarrhea? Mice under stress (like being transported) can die of heart attacks.

Once I bought a frozen rat there and it was INFESTED with mites.

It was definitely out of the anus, and it was his lower abdomen that looked swollen. I don't believe he died of a heart attack. It wasn't diarrhea, either. I've had pet mice and my snakes for a while now and I've seen rodent diarrhea. It was without a doubt a thick pus...

^ This.

This question has had no activity for 14 days and will be closed by an administrator unless the original poster takes action.

Recommended Action: Points awarded

An administrator will select responses and assign points at their discretion.

Original poster, please close this question out and assign points. If you have any further information in the resolution of your problem, please post it here so that others may learn from it.