Plural of virus

There is some controversy about the plural form of virus in the English language.

One position is that viruses is the correct plural; this view can be justified on these grounds:

Wikipedia (see English plural) and most English language dictionaries give the plural of virus simply as viruses.¹
In English, the plural is normally formed by adding -s or -es, frequently in preference to a loan word's native plural.
In Latin, virii is not the correct plural. The "ii" ending only occurs in the plural of words ending in "ius". For instance, take radius, plural radii: the root is radi-, with the singular ending -us and the plural -i.
In Latin, viri is not the correct plural. The ending -i is used only for masculine nouns, not neuter ones such as virus; moreover, viri is the plural of vir, and means "men".
There is no extant record of virus being used in Latin in a plural form, and it is unclear how a plural might have been formed had the word acquired a meaning requiring a plural form.² Possibilities include vira, following the pattern for neuter nouns in -um – or virus with a long "u", following the example of status. However, none of these are attested.

Another position is that virii can also be justified because:

The spelling virii is linked to a specific technical field (computer science), and so is considered jargon.
The term is today an English language term, not Latin.

The spelling virii originates as a humorous usage on warez BBSes and among crackerss in the 1990s. (See Leet. An analogous humorous plural in hacker jargon would be "boxen".) It has no previous use in virology, is not used in medicine, and is used as online slang in reference to computer viruses. Computer professionals unaffiliated with the warez and cracker scenes generally reject it; for instance, antivirus software documentation generally refers to viruses.

However, there are a number of computer professionals who adhere to a more liberal view of linguistics. They are of the opinion that the point of language is communication, and the choice of word is irrelevant as long as the meaning is conveyed and communication occurs.

Footnotes

1. The same is true of specialized dictionaries, e.g.:

2. There is some debate about what the rules of Latin grammar might imply about the formation of a plural. In Latin virus is generally regarded to be a neuter of the second declension, a form so rare that there are no recorded plurals, and so there is no classical rule for forming its plural. Possibilities include "virus" (in analog with 4th declension) and "vira" (in analog with 3rd declension).