Parasitic and Commensal interactions among Mimiviruses, Sputnik-like virophages, and Transpovirons: A theoretical and dynamical systems approach.

Giant viruses have been in the scope of virologists since 2003 when they were isolated from Acanthamoeba spp. Giant viruses, in turn, get infected by another virus named virophage and a third biological entity that corresponds to a transpoviron which can be found in the capsids of giant and virophage viruses. So far, transpovirons seem to behave as commensal entities while some virophages exhibit commensal behavior under laboratory conditions. To study the system's behavior, we used a theoretical approximation and developed an ordinary differential equation model. The dynamical analysis showed that the system exhibits an oscillatory robust behavior leading to a hyperparasitic Lotka-Volterra dynamic. But the biological mechanism that underlines the transpoviron persistence over time remains unclear and its status as a commensal entity needs further assessment. Also, the ecological interaction that leads to the overall coexistence of the three viral entities needs to be further studied.