The Trend Micro scan engine uses an external data file, called the virus pattern file, to keep current with the latest viruses and other Internet threats such as Trojan horses, mass mailers, worms, and mixed attacks (for example, Bagle or NetSky).

All Trend Micro antivirus programs using the ActiveUpdate function can detect the availability of a new virus pattern on the Trend Micro server, and/or you can set it to automatically poll the server every week, day, or hour to get the latest file. Trend Micro recommends that you schedule automatic updates at least daily, which is the default setting for PortalProtect. Whether performed in the background or on-demand, the pattern file updates without interrupting users or network traffic.

You can manually download virus pattern files from the following Web site, where you can also find the current version, release date, and a list of all the new viruses definitions included in the file.