Space, persistence and dynamics of measles epidemics

Area of Science:

• Epidemiology
• Mathematical Biology
• Ecology

Background:

• Pre-vaccination measles epidemics in large urban populations exhibited complex dynamics and persistence.
• Current epidemiological models often fail to simultaneously capture both epidemic dynamics and persistence characteristics.
• Understanding these factors is crucial for predicting and controlling infectious disease spread.

Purpose of the Study:

• To investigate the relationship between persistence and dynamics in measles epidemics.
• To evaluate the ability of stochastic, seasonally forced, and age-structured models to represent epidemic behavior.
• To explore the role of spatial structure in explaining observed measles epidemic patterns.

Main Methods:

• Comparison of epidemic data from England, New York, and Copenhagen using summary measures of persistence and trienniality.
• Analysis of non-spatial and spatial (metapopulation) stochastic models.
• Utilizing detailed spatiotemporal data of measles outbreaks.

Main Results:

• Non-spatial models failed to simultaneously capture persistence and triennial dynamics observed in urban measles epidemics.
• The inclusion of spatial (metapopulation) structure in stochastic models allowed for the coexistence of persistence and triennial dynamics.
• Spatial dynamics are essential for accurately modeling measles epidemics before widespread vaccination.

Conclusions:

• Spatial structure is a key factor in understanding the persistence and dynamics of measles epidemics.
• Metapopulation models provide a better framework for capturing complex epidemic behaviors than non-spatial models.
• The findings have implications for modeling other spatially structured ecological and epidemiological systems.