Absence of Brucella canis Detection in Dogs from Central Italy: Implications for Regional Surveillance and Zoonotic Risk

Background: Brucella canis is a zoonotic pathogen associated with reproductive disorders in dogs and represents an emerging public health concern. Dogs are the only known source of infection for humans, and transmission is often associated with close contact, particularly in occupational settings. Reports of canine and human infections in Europe are increasing, underscoring the need for integrated surveillance to assess the risk of introduction and spread. Objectives: This study aimed to investigate the possible circulation of B. canis in different subgroups of dogs from Central Italy, representing diverse risk contexts (stray, breeding, blood donor, refugee-associated, and previously outbreak-linked dogs), and to generate sentinel data to inform further risk-based surveillance and zoonotic risk assessment. Methods: A comprehensive serological, molecular, and bacteriological survey was conducted on 128 dogs sampled in the Umbria region, covering animals from different backgrounds and risk contexts. Blood samples were tested using bacterial culture, real-time PCR, serum agglutination test, complement fixation test, and/or indirect immunofluorescence antibody test. Results: All tested dogs were negative for B. canis. The upper 95% confidence limit for prevalence was 3.5%, suggesting that widespread circulation is unlikely, although a low/moderate prevalence in specific groups cannot be excluded. Conclusions: Although no cases of B. canis were detected, the results provide sentinel information and highlight the need for continued risk-based surveillance, particularly in low-prevalence areas to prevent introduction of the infection and to enable early detection in case of occurrence. As dogs are the only known source of human infection, veterinary monitoring plays a pivotal role in mitigating zoonotic risks and supporting One Health strategies for evidence-based control.