Figure 2
Representation of the mathematical models. (1) As uninfected, susceptible target cells (T) interact with infectious virions (V) over time, some portion of the latter (\(V^\text {enter}\)) irreversibly enter some of the available target cells, at rate \(\beta T V/s\). (2) Out of these, a fraction \(\gamma \in (0,1]\) will cause the successful infection of \(N^\text {inf}\) target cells, while infection failure of the remaining fraction \((1-\gamma )\) leaves cells in their uninfected state. (3) A newly infected cell will first enter the eclipse phase, and (4) then transition into the infectious phase during which it produces infectious virions at an average rate p, before (5) ultimately ceasing virus production and possibly undergoing apoptosis. (6) At each time step in the SM, a random number of newly produced infectious virions (\(V^\text {prod}\)) are released into the medium or organ compartment of volume \(s\), increasing the infectious virus concentration already present, while \(V^\text {decay}\) infectious virions will lose infectivity, and another \(V^\text {enter}\) will be lost to irreversible cell entry. Terms like \(\beta T V/s\), \(n_E/\tau _E\), \(n_I/\tau _I\), pI, and cV represent the rates at which events take place in the MFM, whereas terms like \(V^\text {enter}\), \(E_i^\text {out}\), \(I_j^\text {out}\), \(V^\text {prod}\), and \(V^\text {decay}\) correspond to the random number of such events over one time step of the SM (see Table 1).
