mGem: Deciphering how polyomaviruses coexist with their hosts for a lifetime

Small DNA tumor viruses such as polyomaviruses have evolved persistent, in some cases lifelong infections despite their compact genomes and host immune pressure. This review synthesizes historical and recent insights into the mechanisms underlying polyomavirus persistence and shedding, including dynamic host cell cycle regulation, viral non-coding control region modulation, and viral microRNA-mediated repression. We highlight modes of shedding consistent with concurrent latent/lytic and smoldering infections, discuss emerging evidence of reversible latency, and identify unresolved questions in viral-host interplay. Understanding these strategies is critical for managing viral reactivation and disease in immunocompromised patients and exemplifies the remarkable evolutionary success of polyomaviruses.