Transferring continuous Android camera feed to PC through USB (in a background app/service)
IP Webcam(see revisions) does allow the access on USB but it will not show you the option to access in its help section. All you've to do is activate USB-tethering on your device, start server on the said app,and access the server by entering 192.168.42.129:8080 in a browser on PC.

I tested this app on my device running Android 4.2.1.