Abstract
The reemergence of the New World screwworm (Cochliomyia hominivorax) poses a significant threat to animal and public health with minimal regulatory oversight. This study analyzes the potential distribution and reemergence of this pest, which is endemic to South America but was previously eradicated in North America. We first developed bioclimatic suitability models, and then incorporated these findings along with reemergence records and inspection point data to simulate possible dispersal routes into Mexico and the United States. Our results document the historical distribution of C. hominivorax across the Americas and recent reemergence events in Panama (2023) and Mexico (2024-2025). Findings indicate high invasion potential from Central America, with significant risk along Mexico's Pacific and Atlantic coasts and the Yucatan Peninsula. In the United States, Texas and Florida face the highest risk. Regions with high livestock density in both countries demonstrate considerable climatic suitability for the pest. Our simulations identify Chiapas, Campeche, Tabasco, and Veracruz as critical northern dispersal points. The invadable areas contain substantial populations of domestic hosts, primarily cattle and horses. These findings will enable governmental authorities to develop comprehensive prevention and control strategies to address this emerging threat.