Serological Evidence of Selected Tick-Borne Pathogens and Dirofilaria immitis in Owned Dogs from Italy and Greece

Canine vector-borne diseases (CVBDs) are caused by pathogens transmitted by several invertebrates, posing a significant threat to both animal and human health worldwide. In recent years, the geographical distribution of CVBDs has changed in many countries, driven by climate change, increased pet travel, movements of goods, and anthropization of wildlife habitats. This study investigated the exposure to major CVBDs in 423 owned dogs from Italy and Greece. Individual serum samples were analyzed using serological methods. The SNAP^® 4Dx IDEXX test was used to detect Dirofilaria immitis circulating antigens and antibodies against Anaplasma spp., Ehrlichia spp. and Borrelia burgdorferi. Additionally, an indirect immunofluorescence antibody test (IFAT) was used to detect antibodies against Rickettsia conorii and Babesia canis. Overall, 171 (40.4%) dogs were positive for at least one pathogen. Antibodies against R. conorii, Ehrlichia spp., Anaplasma spp., B. canis and B. burgdorferi were detected in 118 (27.9%), 28 (6.6%), 29 (6.8%), 5 (1.2%) and 3 (0.7%) dogs, respectively. Dirofilaria immitis antigens were found in 7 dogs (1.6%). A Binomial Logistic Regression was performed and revealed a statistically significant association between age (dogs > 7 years old) (p = 0.005; OR = 1.903; 95% CI = 1.215-2.2981) and presence of at least one clinical sign (p = 0.028; OR = 4.082; 95% CI = 1.168-14.262) and positivity to at least one vector-borne pathogen. These findings confirm that dogs in both Italy and Greece are exposed to a range of vector-borne pathogens and highlight the importance of continuous epidemiological surveillance in European regions.