Mathematical Modeling of the Impact of Aedes Control on Scorpion Population Dynamicsand the Risk of Scorpionism: An Integrated Aedes-Scorpion Control Strategy

Source abstract

Ecological interactions among species of public health relevance can shape health risks in urban and peri-urban environments, with interventions targeting one species potentially generating unintended effects on other populations and, consequently, on human health. In this work, we examine the relationship between Aedes aegypti control, scorpion population dynamics, and the risk of scorpionism through an integrated mathematical model. The two dynamical systems are coupled through interventions targeting Ae. aegypti, allowing us to assess their indirect effects on scorpion populations and the associated risk of scorpion envenomation. To address the question—can coordinated control of Ae. aegypti and scorpion populations more effectively reduce the impact of dengue and scorpionism on human health?—we formulate a coordinated optimal control framework based on the Pontryagin Maximum Principle. This framework enables the joint evaluation of intervention strategies targeting the vector and scorpion populations, accounting for their direct effects on the respective populations and their overall impact on human health. Computational simulations were conducted for São José do Rio Preto, a city in the state of São Paulo, Brazil, where dengue and scorpionism represent concurrent public health challenges. Our results indicate that dengue vector control may generate unintended effects on the risk of scorpionism through alterations in the local ecological equilibrium and scorpion population dynamics. These findings support an integrated approach to dengue and scorpionism control in endemic urban settings, with coordinated interventions offering opportunities to improve control efficiency while simultaneously addressing Ae. aegypti and scorpion-related risks.