"Evolution toward multi-year periodicity in epidemics" 

Masashi Kamo

National Institute of Advanced Industrial Science and Technology

ECOLOGY LETTERS, Vol.8 pp.378-385 (2005)

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Abstract

A long-lasting question in epidemiology is why many childhood diseases show periodicity of more than one year. Previous studies have focused on the dynamical consequence of seasonal forcing in epidemiological dynamics, but few have studied the evolution of seasonality parameters in pathogens. In this paper, we describe our study of the evolution of pathogen's sensitivity to seasonal environment and show that a larger fluctuation in the transmission rate can be favored in the life history evolution of pathogens, suggesting that multi-year periodicity may evolve by natural selection. 

Keywords

Basic reproductive rate, compartment model, evolution in a fluctuating environment, seasonality