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.

The discovery of viruses that are in most ways arenavirus-like with filovirus-like GP2 domains relates to the previously stated hypothesis that envelope glycoproteins from filoviruses and arenaviruses share an ancient common ancestor (44, 45) . There are several possible models to explain the configurations of the extant arenavirus species. One possibility is that the GPC gene of the arenavirus common ancestor was more similar to the GPC gene of CASV and GGV and therefore to those of filoviruses and avian retroviruses (Fig. 7A) . In this scenario, recombination or significant divergence occurred on the lineage leading to the Old World (OW) and New World (NW) arenaviruses. An alternate model is that the GP gene of the ancestral arenavirus was similar to that of the present-day rodent arenaviruses and may itself have derived from an ancestor common with the filoviruses (Fig. 7B) . Then, along the lineage leading to snake arenaviruses, recombination with a filovirus or retrovirus introduced a new GP gene. Intrasegmental recombination between arenaviruses leading to speciation has been documented, so a precedent for these models exists (46) .