Yes, files from BitTorrent are just ordinary files. You can scan them with AVG just like any other file.
If the virus was old enough for AVG to know about it, or obvious enough to make AVG suspicious, then AVG would quarantine it or delete it for you. But if the virus was too new or well-disguised, then AVG (or any other antivirus) would not know that it was a virus and would not do anything about it. This goes for viruses in general, not just ones off of BitTorrent.
Choose torrents that can be confirmed to be "clean".