Evaluation of the Epidemiological Situation B.canis Infections in Human and B.canis Seroprevalence in Diyarbakir, Turkey

Abstract

Brucella canis, which is an infectious agent of dogs, rarely causes disease in human, and displays asymptomatic or subclinical course. Carnivors are natural host for B.canis infection. Considering the limited number of studies investigating the seroprevalence of B.canis in the population in Turkey, a serologic study was planned to investigate of B.canis infection. For this reason, serum samples from the patients who were admitted to Diyarbakir Training and Research Hospital with various reasons other than complaints of an infectious disease were screened using B.canis antigen prepared in Microbiology Laboratory of Harran Univercity, Faculty of Veterinary Medicine to identify the prevalence of this infection in the Southeastern region of Turkey. The serological tests for brucellosis caused by smooth species, (B.abortus, B.suis and B.melitensis etc.) are based on the reaction of antibodies against smooth-lipopolysaccharide (S-LPS) on the bacterial cell wall. But B.canis has a rough-lipopolysaccharide (R-LPS) in its cell wall. Therefore detection of antibodies against R-LPS requires use of specific antigen in serological diagnosis of Brucella infection caused by rough Brucella strains. Unfortunately, a standardized slide agglutination test (SAT) antigen that would serologically detect B.canis and other rough Brucella strains is not commercially available. The present study aimed to investigate seropositivity rate in the patients via SAT using B.canis antigen prepared in laboratory. The study comprised 2100 serum samples obtained from patients (range of age: 16-75 years; 1340 females and 760 males), who presented to various policlinics of Diyarbakir Training and Research Hospital between 01 April 2013 and 31 June 2013. Serum samples were first examined serologically using Standard Rose Bengal test antigen (Refik Saydam Hygiene Institute, Turkey) for the infection with smooth Brucella species, and then negative serum samples were included in the study. Of the 2100 serum samples screened for B.canis using standard slide agglutination test, 33 (1.57%) gave positive result. Fourteen of these 33 patients were female and 17 were male. Seven (21%) of these subjects reported that they had dog in a period of their lives. Their personal history revealed no autoimmune, metabolic or immunosuppressive disease in the past. It is concluded that, B.canis should be considered in the case of fever and infection of unknown origin, particularly in those with the history of contact with dogs. It was also concluded that the development of standardized rapid screening tests is needed for routine serologic diagnosis of brucellosis caused by rough Brucella strains.