Name: Migale Antivirus Suite
Info: Security suite is a set of security software for win32. It contains an antivirus and a smart update tool.
Homepage: http://migaleantivirus.sourceforge.net/
Sourceforge: http://sourceforge.net/projects/migaleantivirus/
Program download is an archive. Contains Docs, Source files and Binaries. I am unsure if it is portable or not, as I do not know how to test it for portability. When I compress the downloaded files using 7-Zip with max compression settings, it compressed the binaries to ~3% of original size, so it is tiny. I thought it would make a nice addition to the PortableApps Suite
This uses the ClamAV database.
There is another open source scanner available - Moon Secure AntiVirus.
It also uses the ClamAV database and has realtime protection plus heuristic scanning. http://www.moonsecure.com/
I have used Moon Secure Antivirus and I like it. It was recently updated a day or two ago.