Plural of virus can't be virii, virii could only be the plural of virius (as in radius, radii) if such a noun existed. Viri would seem more plausible but is also incorrect. Plural of virus is simply viruses, see:
http://en.wikipedia.org/wiki/Plural_form_of_words_ending_in_-us#Virus Michel 2009/7/9, Alexander Hollins <[email protected]>: > ...Hello virii...
