This is a great discussion on a topic that I spend so much time.  The review that Matt sent out is great and I have also inserted a table below that outlines the occurrences as well.  As you can see, it is mainly reported in box turtles.

Box turtles seem to especially sensitive, and I am working compiling the data for a 600 box turtle survey throughout the southeast US that has identified positive free-ranging turtles from several locations.  We have found it in healthy free-ranging and farm-raised terrapins (Trachemys scripta elegans).  This begs the question of the extent of this disease and requires active surveillance and accurate diagnostic assays.  If aquatic turtles can be subclinical carriers of the disease and they are invasive can they spread to new habitats?  I think that this is very possible and an area where researchers should investigate.  I am finishing my PhD dissertation ("Epidemiology of ranavirus in chelonians") and hope to have several other things in chelonians to share with the group this summer on assays, immune response to challenge studies, effect of temperature, and therapeutic approaches.  I am always happy to share and think about more things to do to "save the world one box turtle a time"- a reason I like this listserv.  

I did want to add on to the discussion that Jesse started on free-ranging vs captive.  I believe this is more of a wildlife disease in chelonians, but due to the local epizootics that define this disease in susceptible species, it spills over into captive collections that are monitored more closely (including sites that I am involved with which are close to the report in the article).  As April said (and she and I have brainstormed), this disease can be so rapid in chelonians that they are lost prior to discovery.  Furthermore, aquatic turtles never make it into hoop nets if they are sick and just scavenged after they die.  

Keep up the good work everyone!