Win32:Smadow-G [Trj] Removal – How to Get Rid of Win32:Smadow-G [Trj] Completely?

I was using Avast Mac Security 2015 and I found an infection. The path is labeled /dev/fd/136 and the infection details are Win32:Smadow-G [Trj] I'm assuming that I wasn't very careful at one point and may have downloaded something that contained it. What should I do and how do I get rid of it? Any help would be great.

What is Win32:Smadow-G [Trj]?

Win32:Smadow-G [Trj] is a severe backdoor trojan that can perform different actions, such as executing other malware, to damage your system. It is also detected as Win-Trojan/Zaccess.25600.B (AhnLab), Backdoor.Win32.ZAccess.dg (Kaspersky), W32/ZAccess.G (Norman), Backdoor.ZAccess!W3R2wlUUEiQ (VirusBuster), Backdoor.Win32.ZAccess (Ikarus), Trojan.Zeroaccess (Symantec), and TROJ_SPNR.0BHE11 (Trend Micro). It is dangerous to have this Trojan program in your computer. You can remove it quickly and safely by using Recommended Removal.