When working with bacteria, we use E. coli as a "model organism" and try it first in experiments (because it is cheap, easy to grow, well-studied, etc), and if it works we move on to the bacteria we are really interested in.
When working with viruses, is there an analogous "model organism" to use? Or do we start right off with the pathogens?
if you want to study basic biology of the viruses (e.g. how they enter the cell, how they replicate etc.), you should use the same kind of virus you are interested in (like dsDNA virus with envelope). However, mostly you will probably use right the one you are specifically interested in because there are many differences.