So my point is, of course there have been viruses and malware that affect Linux, but as
http://en.wikipedia.org/wiki/Linux_malware already states, most of them are not dangerous anymore (because they were only risky at the moment that a vulnerability was found and not yet patched), or only affected brave/ignorant users that went ahead and tried to install software in their Linux OS outside of the network of trusted repositories (which, is, BTW, hard to do, so it's not very likely that it happens).
Linux is no different than Windows and people should really stop thinking that there is something magical about it. You don't need to install software as root to infect your machine with malware. Obviously, if you do it the malware has full access to the machine but running a trojan with your own credentials is enough to steal your wallet data. Conversely, if you run with UAC you will have a secure prompt before being able to install software.