Viruses as prey?

[EdRegis]

Ian York writes:

>I must have missed it, because I'm sure that someone in this
>viruses-as-prey thread must have already pointed at hepatitis 
>delta virus, adeno-associated virus, and some of the plant viroids.  
>If not, then I just have.

No one's pointed this out till just now.  Can you expand on this somewhat?
 This is still a notch too cryptic for me to figure out.  Which is prey
for what, and V.V.? 

Ed