Help removing MalWare from my Mac

Hi,

I have recently completed a full scan of my Mac using Sophos Anti-Virus and it discovered the following Malware - Mal/TDSSPk-F .

I visited the Sophos website (as the software won't remove it automatically) to discover how to remove it.  Upon further invesitgation 

I was informed that this is Malware that only effect windows and I don't use windows at all on my Mac.

How dangerous is this Malware and how can I get rid of it manually!

Thank you

Lee