Genotypic Characterization of Brucella Species in Livestock and Abattoir Workers in Sokoto State

Accurate genotyping of Brucella species circulating in Nigerian livestock and human populations is essential for designing targeted control measures and understanding transmission dynamics. This study genotypically characterized Brucella species isolated from livestock and abattoir workers in Sokoto State, North West Nigeria. Blood and milk samples from 180 livestock including cattle and small ruminants, and serum samples from 60 abattoir workers, were collected. Serology-positive samples were subjected to culture on Farrell's medium under biosafety level 3 conditions. Viable isolates were characterized by conventional biotyping and confirmed by Bruce-ladder multiplex polymerase chain reaction. MLVA-16 genotyping was performed on confirmed isolates. Brucella abortus biovar 3 was the dominant species in cattle, and Brucella melitensis biovar 1 was identified in small ruminants. Three abattoir workers yielded Brucella isolates on culture, all matching livestock strains by MLVA-16, providing definitive evidence of occupational transmission. One abattoir worker strain showed a unique genotype not represented in the livestock sample, potentially indicating an unsampled source. The study concludes that multiple Brucella species and biovars co-circulate in Sokoto State livestock, and occupational transmission to abattoir workers is genotypically confirmed. Recommendations include species-appropriate vaccination, biosafety training for abattoir workers, and expanded genotyping surveillance as part of national brucellosis control. Keywords: Brucella, genotypic characterization, abattoir workers, Sokoto State, brucellosis