Actually, there are no such programs for detecting GNU/Linux viruses and
other malware. ClamAV detects Windows viruses so that you don't infect
Windows systems. Viruses for GNU/Linux systems are a curiosity at best right
now, because on most GNU systems the only files they could possibly infect
without you typing your password are those in your home directory.
As mentioned, you're going to be fine if you stick to the repos. If you
don't, you can prevent theoretical serious problems by just not giving any
programs downloaded from somewhere outside the repo root privileges unless
you've checked or had someone else check the source code. The worst that
could happen is your home directory being messed up.
But this is just theoretical right now. Nobody bothers writing malware for
GNU/Linux systems; it isn't worth the effort. You're far more likely to lose
your files to a hard drive failure than you are to lose your files to a
trojan horse or virus. Just keep your system up-to-date and you'll be fine.
