recomended tool to protect against this. MCShieldhttp://mcshield.net it is free, and install and forget
it does not use any system recours as the program is dormant and wake up when a USB storage device is plugged in
it only target those type of malware that use USB device to spread and it only scan root of the device, meaning if you plug in a full 1TB USB HDD it will not scan all files on it, that is for your AV to do
I do run McShield on my laptop which I used to diagnose the flash drive. It’s an awesome app, just wish it could get through the campus firewall (I’m guessing it doesn’t update through port 80) for updates.