supervirulent

"supervirulent" character being usually attained by the method of _passage_ already explained.

Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 2 "Baconthorpe" to "Bankruptcy" Various

And the other piece of this that helps us tone this down is recognizing that within the genomics, the actually RNA, genetic material of this virus are missing the key things that make a virus a supervirulent rapid transmitter between you and I.

CNN Transcript May 4, 2009 2009

CHETRY: Will we see more deaths though in Mexico if it wasn't this supervirulent deadly strain?

CNN Transcript May 4, 2009 2009

At this spring's annual Black Party in Manhattan, one of the big bacchanals on the gay party circuit, volunteers from Gay Men's Health Crisis handed out condoms to a crowd shaken by recent reports that a meth user had contracted what might be a new, supervirulent strain of HIV.

America's Most Dangerous Drug 2007

Sometimes dead bacteria, living virulent bacteria, and living supervirulent bacteria, are used in succession, the object being to arrive ultimately at a high dosage, though the details vary in different instances.

Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 2 "Baconthorpe" to "Bankruptcy" Various