The only thing receiving a lot of notice recently was the Internet Explorer vulnerability that Microsoft supposedly patched, out of sequence, last week. Of course any vulnerability that can be exploited can deliver just about any trojan, but I believe that "Zlob variants" were mentioned in some of the reports.
Even if it's not the browser you use, IE needs to be patched because IE and Windows Explorer are one and the same so you do use it locally.
I haven't seen much on whether the AV makers had the details to develop detections, or if Microsoft kept some of it quiet until their patch was delivered. Countermeasures might be included in the Microsoft Malware Remover that haven't gotten into distribution by all the regular Anti-malware programs as yet, although usually the sharing of problem details is pretty rapid.
The Malware Remover should download and run every time you get an automatic update, unless you've turned it off; but you can update it separately and do a "forced run" from the Windows update site.
No AV picks up everything, so remote scans by other providers might pick up something your regular protection missed, especially if it's something new.