I'm a Mac Technician. And I do believe that Macs may get infected, if not severely so far. Besides, Trojans and fishing mails can spread Macs to Macs via Mail clients often. Therefore, strong Antivirus App that is capable to detect and destroy multi-platform infections is a most for Mac owners.
I recommend Sophos Anti-Virus at this point. You may get Sophos Anti-Virus For Mac Home Edition for free visiting official Sophos site.
I've been using Sophos for last 3 years, and pretty comfortable with it. Have experienced Sophos detecting phishing mails right-away.
How to make sure, your Mac is virus or malware or fishing mails free after installing Sophos?
Open Sophos if it doesn't prompt you to scan your machine. If prompts, just hold on. We've some setups to do.
Click on Preferences.
Check on Scan Inside Archives And Compressed Files if not checked by defaults under Scan Local Drives
Under On-access Scanning, Check on Inside Archives and Compressed Files and Files on Network Volumes.
Select Delete Threat on When A Threat Is Found line.
Enable Live Protection under Live Protection tab. Now close the Preferences Pane.
Click on Scan Local Drives.
Now, as Sophos prompts to begin scan, allow it to scan all drives instead of scanning from the Current Privilege option.
It may take half an hour to a couple of hours depending on the drive spaces it is supposed to scan. But, I suggest to run Sophos scan attempt just before you go to bed at night. So that when you wake up in the morning, your computer is either cleaned or the infected files are quarantined and the warning Sophos Icon is bouncing upon the dock. If such is the case, click on that to see if you have to delete the threat manually in case Sophos is not able to clean itself because of Administrator Privileges. Let me know if you are still little uncomfortable regarding using Sophos or quite not sure if any malware still resides in your system. Help is always available for good friends.