Macs get viruses too
I’m happy to announce that at the beginning of April, 550,000 macs had been infected with a Trojan malware called Flashback through a security hole that apple was aware of for several months.
Apple has since supplied an update to fix the problem. Also, Sophos (a company that supplies AV) analyzed 100,000 Macs and found 1 in 36 had Malware and that 1 in 5 had windows malware which could infect windows machines. So make sure you have AV on your Mac too.