In itinere infections covertly undermine localized epidemic control in metapopulations

Area of Science:

• Epidemiology
• Mathematical Modeling
• Network Science

Background:

• Traditional metapopulation models focus on local epidemic spread within subpopulations.
• Transmission during travel phases (in itinere) is often overlooked in epidemic assessments.
• Existing frameworks may not fully capture disease dynamics in interconnected populations.

Purpose of the Study:

• To extend the Movement-Interaction-Return metapopulation framework to incorporate in itinere contagion.
• To analyze the impact of transmission during transit on epidemic thresholds and spread.
• To investigate how travel-acquired infections influence early-stage outbreak trajectories.

Main Methods:

• Utilized the Movement-Interaction-Return metapopulation framework.
• Explicitly modeled contagions acquired during transit along transportation networks.
• Analyzed epidemic dynamics with the inclusion of in itinere transmission.

Main Results:

• Incorporating in itinere contagion significantly reduces the epidemic threshold.
• Epidemic trajectories show pronounced delocalization when travel transmission is considered.
• These effects are particularly pronounced during the early stages of an outbreak.

Conclusions:

• In itinere contagion is a critical factor influencing epidemic dynamics.
• Metapopulation models must account for transmission during mobility phases for accurate predictions.
• Understanding travel-related disease spread is essential for effective public health interventions.