ClamAV - LibClamAV Error: cli_loaddb(): No supported database files found in /usr/share/clamav

If you get the following error when trying to start ClamAV:

[root@server ~]# /etc/init.d/clamd start
Starting clamd: LibClamAV Error: cli_loaddb(): No supported database files found in /usr/share/clamav
ERROR: Can't open file or directory
                                                          [FAILED]

or another related error:

LibClamAV Error: cl_load(): Can't get status of /usr/share/clamav

You can rebuild the database by using:

cd /usr/share
mkdir -p clamav
chown clamav:clamav clamav
freshclam -v