Abstract
Brucella is a highly monomorphic genus and consist of gram-negative pathogenic species. The disease is a systemic infection that can affect numerous organs and tissues and is shared between animals in a herd. Small ruminants and cattle are typically infected with Brucella melitensis and Brucella abortus, respectively. The presence o Brucella in livestock contributes to massive economic losses as well as veterinary and public health distress in developing countries. Due to its unspecific signs and symptoms that are similar to those of other febrile diseases, its slow growth rate on culture, and the complexity of its serodiagnosis, brucellosis remains difficult to diagnose. In the present study, samples including blood (serum), liver, kidney, spleen and lymph node tissues were collected from 275 animals (180 cattle, 60 sheep and 35 pigs) from 5 abattoirs in the Eastern Cape province, South Africa. A random sampling method was used for this study.Serum samples were tested using Rose Bengal test (RBT) and confirmation was done using Complement Fixation Test (CFT). Tissue samples were screened using the PCR for the detection of Brucella species and positive samples were subjected for culture. The PCR assay amplified Brucella directly from tissues in 77 of 180 cattle, 28 of 60 sheep and no Brucella was detected from the pigs. The direct culture technique detected B. abortus from 23 cattle and 1 sheep whereas mixed infections of B. abortus and B. melitensis were detected from 4 cattle and 3 sheep using AMOS-PCR assay. RBT revealed a seroprevalence of 2.9% (1 of 35), 6.2% (4 0f 60) and 6.1% (11 of 180) from pigs, sheep and cattle respectively. Only 1 cattle sample was confirmed positive on CFT. The result of this study emphasises the importance of using more than one diagnostic technique for the detection of Brucella species in livestock. The sensitivity and time rate of PCR technique suggest that the assay could be used for Brucella diagnosis in livestock from abattoirs. The study further shows again the low sensitivity and specificity of brucellosis serological tests for diagnosis.
