Bloodhound varients usually expolits .lnk vulnerability in the system. Please ensure, you have latest OS patch. Please ensure, you are not allowing your user to run .lnk directly from USB, netwok drives. You can block it through application control feature. Also, keep all your clients defs up to date.
I have checked for Bloodhound.Exploit.446- its relatively new. On Symantec site, there is hardly any information available.
For more information on how to fight infection in a controlled manner, please find the link for step by step process.
Best practices for troubleshooting viruses on a network
http://www.symantec.com/business/support/index?page=content&id=TECH122466&actp=search&viewlocale=en_US&searchid=1326936325747
I have infected systems - now what?
http://www.symantec.com/security_response/infected_systems.jsp