If you think you have a virus the first step is a Safe Mode scan as described at the start of my post
HERE (I realize you don't have BSODs but the virus scan method is the same).
Of course if you have another mouse, try it.
If it is wireless try new batteries.
If it is USB wired then go to sounds and assign a sound to USB devices connecting and disconnecting. Then as you use the mouse if you hear those sounds you will know there is a short in the wire and it needs replaced.
Another possibility is something I had happen related to networking causing your computer to "slow" approximately every 15 minutes. This is generally caused by network info refresh and a drag on your CPU when you have a huge hosts file. If you don't have a large hosts file then this doesn't really apply to you. But if you do then I suggest a freeware product called
HostsMan - run it to remove duplicates and optimize and see if your mouse "stutter" goes away.