Evaluation of Three Serological Tests for Diagnosis of Canine Brucellosis

Abstract

Canine brucellosis caused by Brucella canis, is an infectious disease affecting dogs and wild Canidae. Clinical diagnosis is challenging, and laboratory testing is crucial for a definitive diagnosis. Various serological methods have been described, but their accuracy is uncertain due to limited validation studies. The present study aimed to evaluate the performances of three serological tests for the diagnosis of B. canis in comparison with bacterial isolation (gold standard), in order to establish a protocol for the serological diagnosis of canine brucellosis. A panel of sera from naturally infected dogs (n = 61), from which B. canis was isolated, and uninfected dogs (n = 143), negative for B. canis isolation, were tested using microplate serum agglutination (mSAT), complement fixation performed using the Brucella ovis antigen (B. ovis-CFT), and a commercial immunofluorescence assay (IFAT). The sensitivity and specificity of the three serological methods were, respectively, the following: 96.7% (95% CI 88.8–98.7%) and 92.3 (95% CI 86.7–95.1%) for mSAT; 96.7% (95% CI 88.8–98.7%) and 96.5 (95% CI 92.1–98.2%) for B. ovis-CFT; 98.4% (95% CI 91.3–99.4%) and 99.3 (95% CI 96.2–99.8%) for IFAT. The use in of the three methods in parallel, combined with bacterial isolation and molecular methods, could improve the diagnosis of the infection in dogs.

Brucellosis: Unveiling the complexities of a pervasive zoonotic disease and its global impacts

“…The serum sample can be diluted from 1:2 to 1:64 to counteract excess antibodies that cause false negative results because of the prozone effect, which will increase the test’s specificity ( Mohseni et al ., 2017 ). The failure to diagnose B. canis infection and the development of cross-reactions between IgM immunoglobulins and Francisella tularensis , Escherichia coli O116, E. coli O157, Salmonella urbana , and Yersinia enterocolitica O:9 are drawbacks of the SAT ( Perletta et al ., 2023 ). Modifications such as the inclusion of EDTA, 2-mercaptoethanol, or antihuman globulin can help to overcome some of these inadequacies.…”