Identification, Characterization, and In Vitro Culture of Highly Divergent Arenaviruses from Boa Constrictors and Annulated Tree Boas: Candidate Etiological Agents for Snake Inclusion Body Disease

Stenglein, Mark D.; Sanders, Chris; Kistler, Amy L.; Ruby, J. Graham; Franco, Jessica Y.; Reavill, Drury R.; Dunker, Freeland; DeRisi, Joseph L.

We wondered whether the large NP inclusions that we observed in infected JK cells and infected boa constrictor tissues corresponded to the inclusion bodies that are diagnostic for IBD. We performed hematoxylin and eosin (H&E) staining on sections previously visualized by immunofluorescence and found that this was indeed the case (Fig. 6 ). Many eosinophilic inclusions stained brightly with NP while others appeared to be ringed by NP fluorescence (closed and open arrowheads in Fig. 6 ). This could be explained by differential cross-sectioning of the inclusions during tissue sectioning, for instance, if the inclusions were roughly spherical and coated with NP protein. In this scenario, in equatorial cross sections the NP fluorescence would ring the inclusions. And if the section captured the top or bottom surface of the inclusion, then the fluorescence would appear as filled circles. Alternatively, there may be multiple, structurally distinct types of inclusions, or inclusions may be differentially accessible to antibody during staining.