Latest months I noticed that even if your WHM > cPanel menu > Manage plugins reports that your clamAV is installed correctly , very often it's not true at all .
How to check if your clamd is really installed and running
Go to console and execute this
# whereis clamd
If you receive this
your clamAV is NOT installed (even if your WHM > cPanel menu > Manage plugins reports that your clamAV is installed correctly )
If you receive something like this
clamd: /usr/sbin/clamd /etc/clamd.conf /usr/share/man/man8/clamd.8
your clamAV is installed correctly .
If your clamAV is not installed you can report the problem to cPanel . I reported the problem to cpanel countless way however they always reported me the problem does not exist or they can't replicate it. If we all report the problem to cpanel ,I hope they finally fix the clamAV installer in WHM > cPanel menu > Manage plugins