Low agreement between serological and molecular tests for the diagnosis of cattle brucellosis

Articles in Press

Document Type : Research Article

Authors

• Mehran Ghaemi ¹
• Mohammad Sadegh Golvajouei ²

¹ Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad

² Department of Pathobiology, Faculty of Veterinary Medicine, Shiraz University, Iran

10.22067/ijvst.2025.89499.1412

Abstract

Bovine brucellosis, caused mainly by Brucella abortus, is a significant disease of cows that has created a widespread public health problem in humans. Diagnosis of bovine brucellosis relies on serology, but current serological tests lack sensitivity and, most importantly, specificity. In this study, we tried to compare current bovine brucellosis serological tests in Iran with Brucella spp. antigen detection tests. Also, we examined Brucella species circulating in cows of Fars province, Iran. Additionally, the infection rate of Yersinia entrocolitica O9 strain as a probable interfering agent in Brucella spp. serological tests were evaluated. Supramammary lymph nodes were sampled from 98 Brucella spp. reactor cows of Fars province, Iran, are used for bacterial culture and molecular tests, including conventional, multiplex, and real-time PCRs. Brucella spp. was only isolated from 5.1% of cultured samples and detected in 15 (15.3%) and 21 (21.4%) samples by conventional and real-time PCRs. The species of all Brucella spp. positive samples were determined B. abortus. Most of the seropositive cows were Brucella spp. negative at the time of slaughtering (78.6%) using molecular tests and culture, which showed a high false-positive rate of serological tests for cattle brucellosis. As Y. enterocolitica O9 strain was not detected in any lymph node samples, it could be concluded that immunological cross-reaction with this bacterium was not the reason for the few real-time PCR-positive results among Brucella reactor cows. In conclusion, real-time PCR could provide valuable information about the Brucella species circulating in the slaughtered cows of each region.

Keywords

• Brucella abortus
• Yersinia entrocolitica
• real-time PCR
• serological test

Main Subjects

• Zoonoses

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