A mathematically assisted reconstruction of the initial focus of the yellow fever outbreak in Buenos Aires (1871)

TL;DR

This study combines historical mortality data with a stochastic population model to reconstruct the initial focus of the 1871 yellow fever outbreak in Buenos Aires, providing new insights into its origins and spread.

Contribution

It introduces a detailed, biologically-informed stochastic model to analyze historical epidemic data, challenging previous assumptions about the outbreak's initial conditions.

Findings

Model accurately reproduces historical mortality patterns.

Sensitivity analysis reveals key parameters influencing outbreak dynamics.

Provides plausible alternative scenarios for the epidemic's origin.

Abstract

We discuss the historic mortality record corresponding to the initial focus of the yellow fever epidemic outbreak registered in Buenos Aires during the year 1871 as compared to simulations of a stochastic population dynamics model. This model incorporates the biology of the urban vector of yellow fever, the mosquito Aedes aegypti, the stages of the disease in the human being as well as the spatial extension of the epidemic outbreak. After introducing the historical context and the restrictions it puts on initial conditions and ecological parameters, we discuss the general features of the simulation and the dependence on initial conditions and available sites for breeding the vector. We discuss the sensitivity, to the free parameters, of statistical estimators such as: final death toll, day of the year when the outbreak reached half the total mortality and the normalized daily mortality, showing some striking regularities. The model is precise and accurate enough to discuss the truthfulness of the presently accepted historic discussions of the epidemic causes, showing that there are more likely scenarios for the historic facts.