A few points...
First, viruses don't last forever. Flu viruses only last for 24-48 hrs hard, nonporous surfaces such as stainless steel and plastic, and die much faster on cloth, paper, and tissues. Under conditions of low humidity and room temperature, adenovirus, poliovirus, and herpes simplex virus survived for at least 8 weeks. But nowhere near 3 years.
Secondly, mice and keyboards a places of transmission, not places where the viruses reproduce. They need to be inside bodies for that.
Thirdly, the next superbug is not brewing on anyone's mouse. Viruses cannot recombine without reproduction. And again, that has to happen inside a body.
Fourth point. Everyone needs a certain level of exposure to viruses and bacteria to keep their immune systems operating. In fact, there is a certain level of exposure that makes the immune system work BETTER than the complete absence of pathogens.
There are three amazingly simple things you can do to lower your bacterial/viral exposure load.
1. Wash your hands frequently. All the times your mother told you to (or should have told you to). Before eating, after going to the bathroom, after playing with the dog, or running around on your hands and knees, etc. etc. etc. And do a better job than a splash and a promise. Use soap!
2. Use antiseptic foams or gels in your work areas, frequently. Most have an added benefit of having moisturizers which keep your hands from cracking during the winter.
3. Use a damp, not wet, antiseptic wipe on your mouse and keyboard. Make sure your system is turned off when you do it. And even an alcohol-based screen-cleaner pad would do the trick in a pinch.
