An integrated surveillance and management model for Baylisascaris procyonis in invasive raccoons (Procyon lotor) in Italy.

The raccoon (Procyon lotor), an invasive alien species in Europe, is a known reservoir for zoonotic parasites, particularly Baylisascaris procyonis, which can cause severe larva migrans syndromes in humans and animals. Following the first report of B. procyonis in the raccoon population of the Province of Arezzo, Central Italy, in 2021, we developed and implemented a One Health integrated surveillance and management approach combining carcass collection, parasitological and molecular diagnostics, GIS-based risk mapping, environmental fecal monitoring, and targeted public health outreach. During the study period (2021-2024), B. procyonis was detected in 34 (33.3%) of the 102 examined raccoons. No evidence of infection was identified in 169 examined paratenic hosts, while 30 wolf carcasses and 15 fecal samples from at-risk domestic dogs also tested negative, suggesting no evidence of parasite circulation outside the raccoon reservoir, within the limits of the investigated samples. Genetic characterization of raccoons revealed only one mitochondrial haplotype in all B. procyonis positive raccoons, suggesting a single introduction event of individuals that escaped from captivity in the early 2000s. GIS analysis identified a high-risk core area of 265 km2, characterized by low human activity and the absence of latrines, tracks and other signs confirming the presence of raccoons. These results highlight the importance of raccoons as reservoirs of zoonotic parasites and demonstrate the relevance of a coordinated multidisciplinary surveillance model for assessing and managing emerging wildlife-borne hazards. This integrated approach provides a blueprint for early detection and risk mitigation as raccoon populations are likely to continue expanding across Europe.