Time-delayed spread of viruses in growing plaques

Area of Science:

• Virology
• Biophysics
• Mathematical Biology

Background:

• Classical models predict faster virus spread in growing plaques than experimentally observed.
• This discrepancy is often attributed to uncharacterized biological factors.
• Existing models fail to account for the temporal dynamics of viral replication within host cells.

Purpose of the Study:

• To investigate a purely physical model for predicting virus plaque expansion speeds.
• To determine if incorporating intracellular virus reproduction delay resolves the discrepancy between model predictions and experimental observations.
• To challenge the prevailing notion that biological factors are solely responsible for the observed spread rates.

Main Methods:

• Development of a physical model for viral plaque spread.
• Inclusion of a time delay parameter representing virus reproduction within infected cells.
• Comparison of model predictions with experimental data on plaque expansion speeds.

Main Results:

• The physical model, accounting for intracellular reproduction delay, accurately predicts observed plaque expansion speeds.
• No free or adjustable parameters were required, indicating the model's predictive power.
• The model successfully explains the slower-than-expected spread without invoking complex biological mechanisms.

Conclusions:

• A purely physical model incorporating virus reproduction delay can accurately predict viral plaque spread.
• The discrepancy between classical models and experimental data can be explained by physical factors, not solely biological ones.
• This finding offers a simpler, physics-based explanation for viral spread dynamics.