On the Geographic Spread of Chikungunya Between Brazil and Florida: A Multipatch Model with Time Delay

Abstract. Chikungunya (CHIK) is a viral disease transmitted to humans through the bites of Aedes mosquitoes infected with the chikungunya virus (CHIKV). CHIKV has been imported annually to Florida in the last decade due to Miami’s crucial location as a hub for international travel, particularly from Central and South America, including Brazil, where CHIK is endemic. This work addresses the geographic spread of CHIK, incorporating factors such as human movement, temperature dependency, as well as vertical transmission, and incubation periods, for different patches. Central to the model is the integration of a multipatch framework and the inclusion of human movement between endemic Brazilian states and Florida in the numerical analysis. We establish crucial correlations between the mosquito reproduction number [Formula: see text] and the disease reproduction number [Formula: see text] with the disease dynamics in a multipatch environment, encompassing not only from a theoretical perspective but also from numerical simulations. More specifically, after establishing the well-posedness of the multipatch model problem, we present conditions to ensure the uniform persistence of the disease. Next, using real population and temperature data we are able to determine all parameters that are temperature-dependent for both Brazil and Miami-Dade County and apply a two-patch model to calibrate the CHIK data from Brazil and Miami-Dade County. Finally, via sensitivity analysis we discuss the disease dynamics under different scenarios and make future projections, offering insights for potential effective control strategies, as well as addressing the timing for these strategies to be adopted.