Seroprevalence of Bovine Brucellosis in Selected Districts of Zambia.

Brucellosis is an infectious zoonosis that has huge economic and public health implications globally. The disease is prevalent in humans, livestock and wildlife in Sub-Saharan Africa. A cross-sectional study was conducted between 6 May 2017 and 31 July 2020 during which 1712 sera from 175 cattle herds in five districts from Southern, Western and Eastern Provinces of Zambia were collected and screened against brucellosis. The Rose Bengal Test (RBT) and competitive Enzyme-linked Immuno Assay (c-ELISA) were used in serial testing for the detection of antibodies against Brucella species. A total of 127 animals from 37 herds tested positive, giving overall individual animal and herd-level seroprevalences of 7.53% (95% CI: 6.28-8.78%) and 21.14% (95% CI: 15.0-27.2%), respectively. Namwala district had the highest herd seroprevalence (33.9%, 95% CI: 21.6-46.1%), while Lundazi did not record any seropositivity. Comparably, Southern Province had the highest individual animal (8.97%, 95% CI: 7-11%) and herd-level (28.5%, 95% CI: 20.3-36.7%) seroprevalences, although this was not statistically significant. Within Southern Province, higher seropositivity was observed in Namwala district (OR: 8.55; CI: 2.66-27.44), among female animals (OR: 2.48; CI: 1.38-4.46) and in those aged 11 years and above (OR: 2.67; CI: 1.34-5.34) as well as in gravid cows (OR: 4.34; CI: 2.08-8.92). Seropositivity was also observed among some animals with hygromas (OR: 6.5; CI: 0.45-94.08) and those with a history of abortion (OR: 1.13; CI: 0.18-7.28) although the findings were not statistically significant. Brucella seroprevalence among traditional cattle in Zambia remains high. Control programs against bovine brucellosis must be introduced to reduce its impact on human health and animal production.