How can we detect a virus on our mac?, How can we detect a virus on our mac?

Question

We think we may have a virus from the USPS spam email.  How can we detect a virus on our computer?

Answer 1

What makes you think there is a "virus"?  Any symptoms...?
There are other types of malware (such as trojans) that can affect Mac OS X, but no viruses.  A trojan would have to trick you into installing something (the malware) by making you think it is something else.  You would be notified (by the system) that you are running a downloaded application for the first time, AND if something will be done to update your current system, you will be asked to authenticate (with your admin user name and password).  If something like that comes up when you don't expect it, you should be suspicious (and NOT authenticate).  Just opening an email won't do anything, even if it's an email that may affects Windows PCs.
This free utility can scan your Mac for malware. 
http://www.clamxav.com/
Apparently, there is a version on the Mac App Store.
http://search.itunes.apple.com/WebObjects/MZContentLink.woa/wa/link?path=mac%2fC lamXav
In the past, when I bothered to run it a few times a year, the only things it found were junk emails that I had not bothered to delete with embedded malware, all of it aimed at Windows PCs.