Antivirus protection of downloading emails is not necessary; even Norton and
McAfee have finally admitted this is true.

Norton says:

"..If you disable email protection, is your computer still safe from email
viruses?

Disabling email protection does not leave you vulnerable to viruses and
malicious software in email. It is a separate layer of protection in
addition to Auto-Protect. Auto-Protect scans any incoming files, including
email, as they are saved to your hard drive. As long as you keep your virus
definitions up to date with LiveUpdate, and keep Auto-Protect enabled and
set to scan files as they are created or downloaded, your system is fully
protected."

Somebody at McAfee said:

""You don't have to worry about the e-mail scan as this is a corporate
feature -requiring Outlook 2000 and a mail server such as Exchange server.
Unless you meet the criteria you should make sure that it is disabled. As
long as you have the Download scan and Internet filter enabled you'll be
just fine as these two options effectively checks anything
downloaded -including e-mails. I hope this answers your question. Remember
e-mail scan is for corporate users only"."