A *Salmonella Enteritidis* pandemic emerged in the 1980s, rapidly spreading globally. This study investigates the hypothesis that international trade of infected breeding stocks contributed to this spread. By analyzing over 30,000 *Salmonella Enteritidis* genomes and international live poultry trade data, the study presents evidence supporting the hypothesis. Genetically similar isolates were found in domestically raised poultry across continents, and phylodynamic analysis indicated dispersal from centralized origins. The study establishes a quantitative link between breeding stock trade and the geographic spread of *Salmonella Enteritidis*, highlighting the value of integrative data analysis in understanding pathogen dissemination.

Shaoting Li, Yingshu He, David Ames Mann, Xiangyu Deng