Detection of Brucella spp. in dogs at Pantanal wetlands

Abstract

Canine brucellosis is an infectious disease that produces reproductive disease in both males and females. Although Brucella canis is more common, the infection by Brucella abortus is more frequent in dogs sharing habitats with livestock and wild animals. We decided to investigate the role of dogs in the maintenance of Brucella spp. in the Pantanal wetland. Serum and whole blood samples were collected from 167 dogs. To detect antibodies against B. abortus and B. canis, buffered acidified plate antigen (BAPA) and agar gel immunodiffusion (AGID) tests were performed. To detect Brucella spp., B. abortus and B. canis DNA, PCR was performed using the bcsp31, BruAb2_0168, and BR00953 genes, respectively. To confirm the PCR results, three bcsp31 PCR products were sequenced and compared with sequences deposited in GenBank. The seropositivity rates of 7.8% and 9% were observed for the AGID and BAPA tests, respectively. Positivity rates of 45.5% and 10.8% were observed when testing bcsp31 and BruAb2_0168, respectively, while there was no positivity for BR00953. The sequenced products had 110 base pairs that aligned with 100% identity to B. abortus, B. canis, and B. suis. Considering our results, dogs may be acting as maintenance hosts of Brucella spp. in the Pantanal region.

Keywords: Brucella spp.; Molecular tests; Pantanal; Reservoir host; Serology.

Fig. 1

Electrophoresis of the PCR product in a 2% agarose gel. Lane 1: 100 bp molecular marker (Invitrogen®); lanes 2 to 5: positive samples of BruAb2_0168 (B. abortus); 6: positive control; 7: negative control

Fig. 2

Multiple sequence alignment of bscp31 Brucella genes (from samples 03, 09, and 11, and B. canis, B. abortus, and B. suis from GenBank) using the MEGA 6.0 program