Experimental observation of long time delays near quasineutral planes in HV–DVG betacoronavirus dynamics

Demonstrate experimentally whether the long time delays (critical slowing down) predicted near parameter regimes supporting degenerate normally hyperbolic invariant manifolds (quasineutral planes) by the six-dimensional ordinary differential equation model of helper virus–defective viral genome interactions in betacoronavirus cell cultures can be observed in real experiments.

Background

The paper develops an epidemiological-like ODE model for helper virus (HV) and defective viral genome (DVG) dynamics in betacoronavirus cell cultures that exhibits quasineutral invariant manifolds (planes) composed of equilibria. Near parameter values that generate these degenerate normally hyperbolic invariant manifolds (NHIMs), trajectories display very slow dynamics (long time delays) before approaching equilibrium.

Because experimental passages are run on finite time scales (roughly 24–72 h post-infection) and degradation is small relative to production under these conditions, the authors suggest these long transients might be observable. They explicitly conjecture that such long time delays could be detected experimentally in real systems.