Figure 3.

a. Constraints on viral mutation. Inadequate polymerase fidelity will cause loss of sequence information and quasispcies extinction (A, B), while inadequate viral mutation will result in immune recognition and viral clearance (D,E). Viral persistence requires polymerase fidelity responsive to the host environment (C). 3b. Constraints on viral replication. Overly rapid replication will cause cell lysis, tissue injury and premature host death (A,B), while inadequate replication will result viral latency or clearance (D,E). Viral persistence with optimal evolutionary stability requires a polymerase responsive to the host environment (C).