Validation of an ELISA method for the serological diagnosis of canine brucellosis due to Brucella canis.
In the present study, the validation of an enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of canine brucellosis is described. Two different antigenic extracts, obtained by heat or ultrasonic homogenization of microbial antigens from a wild isolate of Brucella canis bacteria, were compared by ELISA and Western blot (WB). A total of 145 canine sera were used to define sensitivity, specificity and accuracy of the ELISA as follows: (1) sera from 34 animals with natural B. canis infection, confirmed by blood culture and PCR, as well as 51 sera samples from healthy dogs with negative results by the agar-gel immunodiffusion (AGID) test for canine brucellosis, were used as the control panel for B. canis infection; and (2) to scrutinize the possibility of cross reactions with other common dog infections in the same geographical area in Brazil, 60 sera samples from dogs harboring known infections by Leptospira sp., Ehrlichia canis, canine distemper virus (CDV), Neospora caninum, Babesia canis and Leishmania chagasi (10 in each group) were included in the study. The ELISA using heat soluble bacterial extract (HE-antigen) as antigen showed the best values of sensitivity (91.18%), specificity (100%) and accuracy (96.47%). In the WB analyses, the HE-antigen showed no cross-reactivity with sera from dogs with different infections, while the B. canis sonicate had various protein bands identified by those sera. The performance of the ELISA standardized with the heat soluble B. canis antigen indicates that this assay can be used as a reliable and practical method to confirm infection by this microorganism, as well as a tool for seroepidemiological studies.
de Oliveira
Maria Zoraida Daltro
MZ
Laboratório de Infectologia Veterinária, Escola de Medicina Veterinária, Universidade Federal da Bahia, Av. Ademar de Barros 500, 40170-000 Salvador, Brazil.
Vale
Vera
V
Keid
Lara
L
Freire
Songeli Menezes
SM
Meyer
Roberto
R
Portela
Ricardo Wagner
RW
Barrouin-Melo
Stella Maria
SM
D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D015153:Blotting, Western / Q000662:veterinary; D001938:Brazil; D041002:Brucella canis / Q000276:immunology; D002006:Brucellosis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel / Q000662:veterinary; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary*; D005260:Female; D008297:Male; D012680:Sensitivity and Specificity
D000942:Antigens, Bacterial