Worldwide, rats are responsible for major economic losses, including damage to human dwellings and food spoilage. Rats are also important vectors for the spread of numerous diseases to humans and animals. Globalised trading routes facilitate the dispersal of rats and their pathogens, with seaports constituting pivotal entry points and potential hotspots of disease. Rodent control has relied on anticoagulant rodenticides for decades but, over recent years, increasing levels of resistance have been reported and associated with certain mutations in the Vkorc1 gene. This project aims to assess the importance of seaports in the arrival/invasion of rats as hosts of zoonotic pathogens in Portugal. This assessment will rely on an innovative multidisciplinary approach based on next generation techniques, pillared on a strong multi-national team with different but complementary expertise in rodent biology: ecology, rodenticide resistance assessment, rodent-borne diseases, parasitology, genomics and invasion biology. Rats will be captured at four major seaports in Portugal (Lisbon, Funchal, Caniçal and Ponta Delgada) and along a maximum of 20 km radius including the surrounding urban areas of each port. To accomplish this the following aims are proposed: i) evaluation of resistance levels to anticoagulant rodenticides; ii) identification of macroparasite assemblages; iii) extensive characterisation of hosted pathogens (bacteria, viruses and protozoa); iv) inference of rat invasion routes, gene flow with surrounding populations and signatures of adaptive selection using a genomic approach; v) and assessment of penetrability and habitat use of incomer rats in resident populations using GPS tracking. This project encloses a significant applied potential as parameters obtained from robust and complementary datasets will be key for future assessments of zoonotic risk in Public Health management. Overall results will significantly increase the understanding of impacts of rat invasions via seaports, which is critical for the development of strategies to monitor and mitigate those impacts.