Per ISC's report and MS's press news, the Kelihos spam botnet was taken down by Microsft. The signature to detect and destroy the virus will be automatcally pushed to Malicious Software Removal Tool. Microsoft also took a proactive action for filing the court order to get Verisign (the domain registrar) to take down the malicious domains. The kelihos botnet has about 42-45k nodes worldwide and sent 3.8 billions spam mails per day.
AegisLab has released several signatures related to Kelihos or Waledac, we advise our customers to update the latest signatures for safely exploring the world :-)