Canine vector-borne diseases (CVBDs) comprise a group of infectious diseases caused by a wide range of pathogens transmitted by arthropod vectors. Clinical signs commonly involve symptoms such as fever, anorexia, weight loss, blood disorders, hepatosplenomegaly, and others that can lead to death in dogs with comorbidities. Some pathogens responsible for CVBDs constitute a serious threat to human health due to their zoonotic transmission. This study aimed to determine the prevalence of zoonotic vector-borne diseases (Rickettsia rickettsii, Anaplasma phagocytophilum, Ehrlichia canis, Bartonella henselae, and Leishmania infantum) in domestic Sardinian dogs with and without clinical signs of these pathogens. Blood serum samples were collected from 142 dogs and examined through serological analysis. Clinical signs suggestive of these pathogens were also evaluated. The results obtained showed that 33 (33/140; 23.6%), 22 (22/134; 16.4%), 14 (14/142; 9.9%), 20 (20/66; 30.3%), and 26 (26/108; 24.1%) dogs were seropositive for Rickettsia sp., Anaplasma sp., Ehrlichia sp., Bartonella sp., and Leishmania sp. antibodies, respectively. Among these dogs, 12 dogs presented with at least one clinical sign (8.5%), while 18 (12.7%) showed more than two symptoms at the same time. Furthermore, among the asymptomatic dogs (93/142; 65.5%), 13% (n = 12) tested positive for A. phagocytophilum, 12% (n = 11) tested positive for B. henselae, 9% (n = 8) tested positive for E. canis, 12% (n = 11) tested positive for L. infantum, and 19% (n = 18) tested positive for R. rickettsii. This survey represents the first study assessing different canine vector-borne pathogens in dogs from North Sardinia. Since the pathogens detected here represent emerging zoonotic diseases, these results highlight the need to undertake further studies to increase the knowledge of these under-reported vector-borne pathogens in Sardinia.

Coxiella burnetii, the etiological agent of Q fever, is a globally distributed zoonotic pathogen affecting both animals and humans. Despite its known endemicity in various Mediterranean regions, data on human seroprevalence in Sardinia are still lacking. This study aimed to assess seroprevalence in patients and to analyze the annual positivity rate related to the serum samples collected in Sardinia over a ten-year period (2015–2024). For this purpose, a total of 1792 patients were involved in the survey, and 4310 serum samples were analyzed using indirect immunofluorescence assay (IFI) to detect IgM and IgG antibodies against C. burnetii. The global seroprevalence rates relating to all the patients over a ten-year period were determined along with the annual positivity rate and trends from all sera. An overall seroprevalence of 27.0% and an average of annual positivity rate of 16.0% were determined, with the IFI detecting IgG antibodies in 15.2% of positive samples and IgM antibodies in 0.9%, suggesting significant prior exposure of the population evaluated. Annual positivity rates ranged from 24.8% in 2016 to 8.0% in 2020. These results confirmed the endemic circulation of C. burnetii in Sardinia and the ongoing risk of human exposure. A GIS-based map was built to evidence the spatial distribution of Q fever in Sardinia. Interestingly, areas with higher seroprevalence appear to coincide with the distribution of sheep and goat farms, indicating a link between livestock and human exposure. These findings confirm the circulation of C. burnetii in Sardinia and underscore the importance of epidemiological monitoring, public health interventions, and educational efforts in populations at increased risk.