Zoonotic pathogens in fallow deer (Dama dama) from Sicily (Southern Italy): implications for wildlife–livestock–human interface

Increasing interactions among wildlife, livestock, and humans have enhanced opportunities for pathogen transmission, raising concerns for both animal and public health. In Sicily, the expansion of fallow deer (Dama dama) populations and the widespread presence of extensive farming systems may facilitate the circulation of zoonotic and vector-borne pathogens. This study investigated the occurrence of Toxoplasma gondii, Leptospira spp., Coxiella burnetii, and selected tick-borne pathogens (Babesia spp., Theileria spp., Anaplasma spp., Rickettsia spp., and Borrelia burgdorferi sensu lato) in 56 fallow deer carcasses collected through population control programs in Sicily between 2023 and 2025. Multiple tissue samples, including spleen, liver, heart, kidney, and lymph nodes, were collected from each animal for DNA extraction and molecular analyses. Pathogen DNA was detected by real-time PCR targeting the 529-bp repeat element (T. gondii), 16S rRNA and lipL32 (Leptospira spp.), IS1111 (C. burnetii), and ospA (B. burgdorferi s.l.). Conventional PCR followed by Sanger sequencing targeted 18S rRNA (Babesia spp. and Theileria spp.), 16S rDNA (Anaplasma spp.), and rOmpB (Rickettsia spp.).

Toxoplasma gondii DNA was detected in 4/56 animals (7.1%), while Leptospira interrogans was identified in 1/56 (1.8%). No samples tested positive for C. burnetii or B. burgdorferi s.l. Piroplasm DNA was detected in 8/56 deer (14.3%), Anaplasma spp. DNA in 43/56 (76.8%), and Rickettsia spp. DNA in 2/56 (3.6%). Sequence analysis identified Theileria cervi, Theileria ovis, Theileria capreoli, Anaplasma phagocytophilum, and Rickettsia slovaca. These findings demonstrate that free-ranging fallow deer may serve as reservoirs of several zoonotic and vector-borne pathogens, highlighting the importance of integrated wildlife surveillance within a One Health framework to support the prevention of interspecies pathogen transmission.

This study was funded by the Italian Ministry of Health (Grant No. GR-2021-12373930).