12Oct/090
Manually Update ClamAV Virus Definitions
Procedure
Visit the ClamAV website for the latest definitions (you have to right click and choose save link as… on the menu) and save them in your home directory, or just open up a terminal and do this..
wget http://db.local.clamav.net/main.cvd
then..
wget http://db.local.clamav.net/daily.cvd
and..
sudo mv daily.cvd main.cvd /var/lib/clamav
Which will move the newly downloaded files to the correct /var/lib/clamav directory.
Now enter your admin password & you should have completely up to date virus definitions
WARNING: This will only work if the ClamAV team use the same link every time for the daily updates?
Source