Mac users interested in Antivurus mac os x 10.5.8 generally download:
ClamXav is a free virus scanner for Mac OS X. It uses the very popular ClamAV open source antivirus engine as a back end and has the ability to detect both Windows and Mac threats. ClamXav can be setup up as passive or active: scan only the files you tell it to or your entire hard drive
AVG AntiVirus is a very capable program that helps you get rid of all viruses and spyware from your Mac. The application brings you a simple and nicely-designed interface, so all Mac users, no matter their computer experience, can easily handle this antivirus utility.