Brucella species circulating in smallholder dairy cattle in Tanzania

Brucellosis is a zoonosis caused by bacteria of the genus <i>Brucella</i>, which results in economic losses relating to livestock and threatens public health. A cross-sectional study was conducted to determine the molecular prevalence of <i>Brucella</i> species in smallholder dairy cattle in six regions of Tanzania from July 2019 to October 2020. Dairy cattle (n = 2048) were sampled from 1371 farms. DNA extracted from blood and vaginal swabs was tested for <i>Brucella</i> using qPCR targeting the IS711 gene and positives were tested for the alkB marker for <i>B. abortus</i> and BMEI1172 marker for <i>B. melitensis</i>. The molecular prevalence was 3.5% (95% CI: 2.8–4.4) with the highest prevalence 8.1% (95% CI: 4.6–13.0) in Njombe region. <i>B. melitensis</i> was the predominant species detected (66.2%). Further studies are recommended to understand the source of <i>B. melitensis</i> and its implications for veterinary public health. Livestock keepers should be informed of the risks and biosecurity practices to reduce the introduction and control of <i>Brucella</i>. Cattle and small ruminant vaccination programs could be implemented to control brucellosis in high-risk populations in the country.