Well, the most popular antivir program is called "ClamAV". You may search for it.
But, look, UNIX (and thus Linux) have a sophisticated permission management system, so you would have to explicitely grant a virus the permission to harm your system. It can "just" destroy your $HOME file. (If you want to prevent this, define an alias for rm
However, Linux has a too small marketshare to be attractive enough for crackers.
The game is not worth the candle.