Invasive Alien Squirrels (Callosciurus erythraeus): Impacts of the Animal Trade and Health Assessment in Northern Italy

Biological invasions are a primary driver of biodiversity loss and pose significant economic and health risks. Among invasive mammals, the Pallas’s squirrel (Callosciurus erythraeus) is of particular concern in Europe due to its competition with native species and its adaptability to urban environments. In Italy, the species is currently established in Lombardy, where it is subject to strict EU regulations and national eradication plans. Despite its invasive status, data regarding the pathogens carried by C. erythraeus remain scarce, hindering accurate disease risk assessments for both wildlife and humans. This study, part of a broader monitoring project in Northern Italy, investigates the health status of the species through necropsies of 99 individuals collected during the LIFE EC-SQUARE project. The research provides a comprehensive screening of macro and microparasites, aiming to identify potential "pathogen pollution" and zoonotic risks. These findings are essential for understanding the epidemiological role of Pallas’s squirrels and for developing effective management and conservation strategies in invaded territories.