One Health approach for Brucella canis: Serological and molecular detection in animal-hoarding individuals and their dogs.

Animal hoarding disorder (AHD) is classified as a psychiatric obsessive-compulsive condition characterized by animal accumulation and often accompanied by unsanitary conditions and animal cruelty. Although AHD may increase pathogen transmission and spread, particularly for zoonotic diseases, human and dog exposure in such cases has yet to be fully established. Accordingly, this study aimed to assess Brucella canis in 19 individuals with AHD (11 households) and their 264 dogs (21 households) in Curitiba, the eighth largest city in Brazil, with approximately 1.8 million habitants. Anti-B. canis antibodies were detected by the 2-mercaptoethanol microplate agglutination test (2ME-MAT) and by a commercial lateral flow immunoassay (LFIA), while molecular detection of previously positive seropositive samples was performed by conventional PCR. Although all the human samples were 2ME-MAT negative, 12/264 (4.5%, 95% Confidence Interval: 2.0–7.0%) dog samples were 2ME-MAT and LFIA positive, with 2ME-MAT titers ranging from 20 to 640. At least one dog in 4/21 (19.0%, 95% CI: 2.0–46.0%) households was seropositive. Despite the absence of seropositivity in individuals with AHD and the comparatively low seroprevalence in dogs, B. canis circulation and outbreaks should be considered in such human populations due to the high burden and recurrent character of B. canis exposure in high-density dog populations and the constant introduction of susceptible animals. Author summary: Individuals with animal hoarding disorder (AHD), a psychiatric obsessive-compulsive disorder, are considered among the most vulnerable people due to their precarious sanitary conditions and exposure to several zoonoses, including canine brucellosis, a neglected and underreported disease of public health concern worldwide. Close and continuous human contact with unhealthy and unassisted dogs may increase pathogen transmission and spread, which is worsened by elderly people's difficulty accessing health services and lack of hoarding control and management programs. The present study assessed B. canis as a silent pathogen in this hard-to-access vulnerable population, along with their dogs. Although all the individuals with AHD included herein were seronegative and their dogs presented relatively low seroprevalence, B. canis infection and outbreaks should always be considered, particularly due to unsanitary household conditions, the high density of dog populations, and the constant introduction of susceptible dogs of unknown origin. Thus, dogs seropositive for B. canis living in households of people with AHD should be considered a warning to local public health authorities. In conclusion, serological and molecular assessments of B. canis in people with AHD and other vulnerable populations may serve as instruments for effective public health policies, including diagnosis, control, monitoring, and prevention. [ABSTRACT FROM AUTHOR]