Linux does not need an antivirus.
completely wrong.
any PC, ANY, need anti-virus software.
viruses are written for all OS's but because Linux has what, 1% global share, the idiots that write viruses care less for those non-mainstream OS's.
the hours spent perfecting their malicious code versus the potential target audience is much more in their favour with MS, they simply have no care factor for anything else.
so are there viruses for Linux?, Yes indeed, but granted, not many, just like the OS itself - it's all relative.