Dynamics and selection of many-strain pathogens in Dengue virus

Rafael Lopes

Yale University

"Dynamics and selection of many-strain pathogens in Dengue virus"

Dengue virus (DENV) has been causing outbreaks and epidemics over the course of the whole XX century. Recently, the size of the seasonal epidemics has been sequentially reaching record-breaking numbers, in 2023 WHO reported globally a record of over 6.8 million infections, and last year the WHO reported again a record-breaking number of confirmed cases, with over 10.5 million confirmed cases. Mainly those confirmed cases have happened in the Americas which has reportedly been affected by different serotypes of the virus. The region of Central America and the Caribbean is mainly affected by DENV3, while the South America region is affected in major number by the DENV1 and DENV2 serotypes. This situation raises the concern of how immunity and the ecological niche of the serotypes works and how this can be better understood to help design plans of contingency. To do so, we have adapted a well-known model to many-strain pathogen dynamics from the point of view of the strains. The model keeps the dynamics simple while being robust in incorporate as many as needed different strains. We modified the model to first reproduce the dengue dynamics in human and mosquitoes population, from that we change the demographics of each population to study how different relative time of infection to life span can give rises to different effects in the strain space and infection niches. All four serotypes have almost total homotypic immunity and, in the short term, heterotypic immunity. The goal here is to have a simple formulation for all the four serotypes and understand how this different dynamical regimes on different hosts affect i) the emergence of niche to the strains, and ii) how it determines endemicity of the disease in humans.

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