Molecular detection and characterization of Brucella species in raw informally marketed milk from Uganda

Abstract

This study identified and characterized Brucella species in the informal milk chain in Uganda. A total of 324 cattle bulk milk samples were screened for the genus Brucella by real-time PCR with primers targeting the bcsp31 gene and further characterized by the omp25 gene. Of the samples tested, 6.5% were positive for Brucella species. In the omp25 phylogeny, the study sequences were found to form a separate clade within the branch containing B. abortus sequences. The study shows that informally marketed cattle milk in Uganda is a likely risk factor for human brucellosis and confirms that B. abortus is present in the cattle population. This information is important for potential future control measures, such as vaccination of cattle.

• Africa
• brucellosis
• bulk milk
• milk delivery chain
• PCR
• bcsp31
• omp25

Acknowledgements

The authors wish to acknowledge Dr. Krishna Gopaul at the Animal Health and Veterinary Laboratories Agency (AHVLA) Brucella research division, Weybridge, UK, for assistance with extraction of bacterial DNA; Dr. Michelle Wille at the Zoonosis Science Center, Uppsala University, Sweden, for assisting during the phylogenetic analyses; and Dr. Anna Rosander at the Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden, for kindly providing the bacterial strains Pseudomonas aeruginosa B683 and Treponema T2378. Additionally, the authors wish to express their gratitude to the milk sellers and milk deliverers for their generous cooperation.