A Systematic Review and Meta-Analysis on the Prevalence of Brucella melitensis in Sheep and Goat

Brucellosis is one of the neglected zoonotic diseases (NZD) in the world that causes disease globally. Brucella melitensis, one of the organisms responsible for causing the disease in sheep and goat, is responsible for the disease in humans. The disease is transmitted mainly from sheep and goat to humans via ingestion (typically through milk), inhalation, abrasion and so on. Despite the zoonotic importance of the disease, there is lack of comprehensive data such as overall prevalence around the world is yet to be measured. The aim of this study is to review all the available articles on the prevalence of the infection in sheep and goats systematically and determine the overall prevalence around the world. Therefore, a literature search was conducted in PubMed for articles published from January 2010 to December 2023 on the relevant topic. The inclusion criteria were set to extract relevant data from the selected articles. A random effect meta-analysis model was used in analysing the data. The derived prevalence was presented in percentage along with 95% confidence interval (CI). The pooled prevalence of B. melitensis infection globally in goat was 2.46% (95% CI: 1.70%-3.21%) and in sheep was 8.07% (95% CI: 6.36%-9.78%); the combined pooled prevalence in both sheep and goat was 5.54% (95% CI: 4.63%-6.45%). Overall, on the basis of regions, the pooled prevalence in goat ranged from 0.07% (95% CI: -0.08% to 0.22%) to 16.82% (95% CI: 12.69%-20.95%). In sheep, the regional pooled prevalence ranged from 0.03% (95% CI: -0.03% to 0.08%) to 60.39% (95% CI: 58.50%-62.27%). This systematic review and meta-analysis demonstrated the global burden of B. melitensis infection in sheep and goat that would help better understanding the global distribution of the infection and the potential areas of zoonotic transmission. The data have been retrieved from various types of journals with different types of study designs and were analysed to highlight the variation of prevalence across the countries, among different species, diagnostic methods and sample sources. This knowledge would help in planning effective control measures targeting high risk species, areas and so on.