Spam and virus folder generation problem

Hi,
i have a virtual server using virtualmin/webmin
and i have set it up using spamAV scanner to NO and ClamAV and antivirus scanner to NO
I dont get lots of emails so i didnt enable it. I thought by not enabling it, it would work more slowly.

I dont know though if this is the reason for the thing below.

I have created some user account on the virtual server but when I add a mail account on thunderbird, it syncs folders but only spam folder is created and not virus folder
also the spam folder is a subfolder of Trash which is the first time that I see something like that.
In other mail accounts of other virtualmin installed in other servers, users have spam and virus folders listed in the same folder with Inbox, Sent,Trash, Drafts
Is there any problem that these folders are not in the main directory and that virus folder is not being created?
I am starting to thing that this is an issue that I am not informed and that maybe i am not protected from viruses and spam.
How can I check if there is a problem or not?