From ZDNet News:
According to a report released Monday by antivirus company Sophos, China–including Hong Kong–hosted 44.8 percent of the world’s infected sites in August. The U.S. ranked a distant second, hosting 20.8 percent of sites that contain malicious code.
The number of infected Web pages has also grown. Sophos said it detected an average of 5,000 new infected pages each day in the month of August.