"Virusoids" Natural Recordings by Native Speakers
Virusoids are small, single-stranded RNA molecules that are similar to viruses, but do not contain a protein coat or capsid. They consist of a genetic core, which is an infectious agent of other viruses. They are single-stranded, circular or linear molecules of RNA, usually less than 1,500 nucleotides long.
I couldn't find any meaning or definition for the word "virulented". It seems to be a non-standard or made-up word.