Historically, our understanding of disease-host systems has been built

upon a population-based rather than community-based approach:

epidemiologists have traditionally studied infectious disease at the

level of a single pathogen species infecting a single host species. This

has led to a significant body of epidemiological research devoted to

understanding the precise mechanisms underlying host-pathogen dynamics in

isolation: an oversimplification of the web of ecological and

immunological interactions in which hosts and their pathogens persist and

evolve. In this talk, I will briefly discuss the potential for

interactions amongst multiple pathogens and apply a general theoretical

framework for their study to the case of dengue: a mosquito-borne

multi-strain disease.

To understand how alternative hypotheses concerning dengue infection and

transmission may explain observed multi-annual cycles in disease

incidence, I adopt a mathematical approach that incorporates both

ecological and immunological mechanisms. Contrary to perceived wisdom,

patterns generated solely by antibody-dependent enhancement or

heterogeneity in virus virulence are not consistent with

serotype-specific notification data in important ways. Furthermore, to

generate epidemics with the characteristic signatures observed in data, a

combination of seasonal variation in vector demography and, crucially, a

short-lived period of cross-immunity is sufficient. Finally, I

demonstrate how understanding the persistence and eradication of dengue

serotypes critically depends on the alternative assumed mechanisms.