Should the abbreviated forms of Latin terms be placed in italics?
When writing English, one often uses Latin terms, such as exemplī grātiā, opere citātō, and id est, but in abbreviated forms, "e.g.", "op. cit.", and "i.e.". When writing Latin terms in English, one often places them in italics. Should the abbreviated forms of such Latin terms also be placed in italics?
According to this guide it is not required:
"Observe that it is usual to write Latin abbreviations in italics, but this is not strictly essential, and many people don't bother."
I read a fair amount of non-fiction publications with copious use of these abbreviations and cannot recall having ever seen them italicized.
According to the official European Union's Style Guide, Latin abbreviations should not be italicized:
Latin abbreviations and phrases
Latin should be used sparingly as even the common phrases are often misused or misunderstood.
(i) Write all Latin abbreviations in roman.
e.g., et al., et seq., ibid., i.e., NB, op. cit.
(ii) Latin words should usually be printed in italics (e.g. ex ante), but certain common Latin phrases take roman (refer to the New Oxford Dictionary for Writers and Editors for italic or roman style).
Examples of roman:
ad hoc, ad infinitum, per capita, pro forma, status quo
Latin phrases are not hyphenated when used adjectivally, e.g. ad hoc meeting.
(Though I have seen them in italics in templates of some academic conferences such as the IEEE Conference on Computer Vision and Pattern Recognition (CVPR).)