AntiVirus for Mac running parallels
Any virtual machine installed will require its own, self-contained antivirus program. For example, I run Parallels Desktop 9 with XP, Windows 7 and Linux CentOS 6 VMs. On XP and Windows 7, I use Microsoft Security Essentials and ClamAV on the Linux VM. On OS X, I am running Kaspersky Internet Security.

The reason that each OS requires its own A/V software is that each VM is a self-contained environment that is essentially sandboxed. Although there is some sharing mechanisms in place, essential services, e.g., antivirus, cannot cross OS boundaries. To allow so would be a serious security vulnerability.