Serosurvey of Rickettsia spp. and Ehrlichia canis in Dogs from Shelters in Sicily (Southern Italy).

Vector-borne diseases represent a serious threat to human and animal health, especially where environmental conditions favor pathogen-carrying vectors. Dogs serve as natural hosts for two tick-borne pathogens: Ehrlichia canis, which causes canine monocytic ehrlichiosis, and spotted fever group (SFG) Rickettsia spp., a zoonotic threat in the Mediterranean region. Rhipicephalus sanguineus is the primary vector for these pathogens. Shelter dogs, due to increased exposure to ticks and confined living conditions, facilitate the spread of vector-borne pathogens, raising the risk of zoonotic transmission. This study conducted a serological survey of 1287 dogs from two shelters, assessing exposure to Rickettsia spp. and E. canis and examining the influence of demographic and environmental factors. Seroprevalence rates were 41.8% for Rickettsia spp. and 24.5% for E. canis, with 14% of dogs positive for both pathogens. No significant association was found with sex or breed. A higher seroprevalence was observed in dogs older than 12 months and in those from the shelter on the Mediterranean coast compared to those from the Tyrrhenian coast, likely due to climatic differences. The study highlights the role of climate in disease spread and the need for public health interventions, supporting One Health initiatives to prevent zoonotic disease transmission.