Abstract
Background and Objectives: Climate change is modifying the ecological and climatic conditions that influence the distribution and activity of arthropod vectors. Rising temperatures and prolonged warm seasons have favored the establishment of Aedes albopictus in Mediterranean regions, increasing the risk of autochthonous Dengue transmission. Therefore, this study describes the evolution of Dengue surveillance in Sardinia between 2018 and 2024, integrating human and entomological data to assess trends, system performance, and implications for prevention and control. Materials and Methods: Data on human cases were retrieved from national notification systems (namely PREMAL, arbo.iss.it) and the New Health Information System. Entomological surveillance data were obtained from the Experimental Zooprophylactic Institute of Sardinia. Mosquitoes were collected using BG-Sentinel(®) traps and ovitraps, covering major cities and points of entry. Descriptive analyses were conducted for both datasets. Results: Sixteen Dengue cases were reported during the study period, all imported and laboratory-confirmed in 81% of cases. Most patients were adults (mean age 38 years), and 77% required hospitalization. The most frequent travel origins were Southeast Asia, Africa, and Latin America. No autochthonous cases were identified. Entomological surveillance showed a progressive increase in Aedes albopictus captures from 2020 onwards, with seasonal peaks between September and October. Despite intensified sampling and expanded geographic coverage, no mosquito pools tested positive for the Dengue virus. Conclusions: Although no locally acquired Dengue infections have been detected, the widespread and increasing presence of Aedes albopictus indicates that Sardinia meets the ecological prerequisites for possible autochthonous transmission. Strengthening the timeliness and completeness of human surveillance, improving clinicians' awareness of reporting requirements, promoting vaccination for travelers, and maintaining continuous entomological monitoring are essential to prevent and promptly manage future outbreaks.