What your seeing is just normal fallout from the Netsky family of viruses.

The body can also be appended with the following string:

Or you can view the message at:
www.[Recipient_Domain]/inmail/[Recipient_Name]/mread.php?
sessionid-[Random_Number]

Note: [Recipient_Domain] and [Recipient_Name] are taken from the email address of the recipient.
Since March 1st my gateway has blocked/trapped/quarantined over 60 thousand copies of Netsky, don't get freaked out, just make sure you keep your AntiVirus software up to date.

Cheers: