Vector-borne pathogens such as Erlichia canis and Rickettsia conorii are widespread in the Mediterranean basin. Rhipicephalus sanguineus, is considered the main vector in Mediterranean climatic areas. Seroprevalence in dogs is variable in relation to environmental factors, presence of vectors, and dogs’ management. We investigated the seroprevalence in Sicilian dogs during 2017–2019, considering temporal as well as spatial variations, and different canine population. A total of 11,009 sera were analyzed: 7568 and 3441 sera were tested to detect antibodies to E. canis and to R. conorii, respectively, by immunofluorescence assay. The rainfall average in the sampling sites during the three-year period was also considered. Statistical analyses were performed using chi-square tests for association between two or more variables. We reported a prevalence of 29.6% and 53.6% for E. canis and R. conorii, respectively. Significant temporal variation was found in R. conorii, while significant difference was found considering canine population and spatial variation regarding both pathogens. Our study updates the previous results of E. canis and R. conorii seroprevalence in dogs in Sicily, and confirms the wide distribution of these pathogens. In addition, we considered, for the first time, three different variables to identify the areas and the canine populations most exposed to risk.

Tick-borne diseases in horses are considered an emergent problem worldwide; the geographical redistribution of ticks, due to climatic and ecological changes, and the movements of infected horses between different nations play important roles in the spread of tick-borne diseases affecting these hosts. In this study, a survey was planned to estimate the seroprevalence of the Gram-negative bacterium Anaplasma phagocytophilum and the piroplasmid protozoa Babesia caballi and Theileria equi in Italian horses, as well as to evaluate possible risk factors associated with seropositive cases. Serum samples from 261 horses reared in northern Italy were collected and analyzed by indirect immunofluorescence antibody test for the detection of A. phagocytophilum-, B. caballi- and T. equi-specific antibodies. The overall seroprevalence to at least one of the investigated pathogens was 51%; sixty-one horses were seropositive to A. phagocytophilum (23.4%), forty-nine to B. caballi and the same number to T. equi (18.8% each). Seropositivity for more than one of the investigated agents was detected in thirty-two horses and the most common co-infection was observed between B. caballi and T. equi (5.7%). A significant risk factor for all the three pathogens was the elevation above sea level; indeed, the risk of infection was higher with an increase and decrease in elevation for A. phagocytophilum and for B. caballi and T. equi, respectively. Tick control in horses is strongly recommended considering the high seroprevalence values of transmitted pathogens.