Systematic Pathologic Findings Report of Callosciurus finlaysonii (Horsfield, 1823) (Rodentia, Sciuridae) Squirrels from Maratea Area (South Italy) to Investigate Species-Specific Pathologies, Reliability of CO(2) Euthanasia Method, and Possible Use as Environmental Sentinels

SIMPLE SUMMARY: Sciurus vulgaris has been considered by the International Union for Conservation of Nature (IUCN) due to the risk of extinction caused by the invasion of the invasive species (IAS) such as Callosciurus finlaysonii Horsfield, 1823. This species originated from Southeast Asia and it was introduced in Italy, in 1980. These animals could cause the extinction of the autochthonous counterpart and might also represent a concern, due to the progressive and unavoidable invasion of urban areas. ABSTRACT: The aim of the present study was to macroscopically and microscopically describe the main pathological findings occurring in this invasive species, in order to better understand the real risks for naïve animals and humans. The present study was conducted on Callosciurus finlaysonii squirrels (n = 165), captured in the Maratea area and euthanatized with CO(2) according to a population control of invasive species of the Italian Agriculture Ministry project (ex CIPE project) and conferred to the Department of Veterinary Medicine of Bari (Italy). Macroscopic analysis demonstrated heart, lung, and liver congestion, probably due to the euthanasia method, and variable lesions of bowel, liver, and kidney. The microscopically examination showed the presence of lymphocytic infiltration in the lower layers of the bowel, suggesting enteritis. To the best of our knowledge, this is the first systemic report of gross and microscopical anatomopathological lesions in C. finlaysonii, in South Italy. The results could be useful to fill a gap of knowledge of this species in Italy.