[nertzy]

Neuter nouns of the second declension don't generally have plurals that end in -i, but rather in -a, so "vira" would be equally possible.

It's also important to note that scholars don't actually know the proper plural of virus because they haven't really found one in extant literature.

Wikipedia has a longer discussion at http://en.wikipedia.org/wiki/Plural_of_virus#Virus

[mistermann]

Doo doo doo doo, doo doodoo do, Doo doo doo doo, doo doodoo do, Doo doo doo doo, doo doodoo do, Doo, doodoodoo, doo doo doo doo doo....

A bit hard to communicate, but that's the keyboard cat playing all of you off.