Spatio-temporal Distribution of Human Brucellosis in Eritrea: 2015 - 2019

Abstract

Human brucellosis remains a significant zoonotic threat in livestock-dependent regions, yet its epidemiology in Eritrea is poorly characterized. This study retrospectively investigated the spatio-temporal distribution and demographic factors associated with human brucellosis in Eritrea using five years of national passive surveillance data. A retrospective cross-sectional analysis was conducted using 3,138 suspected human brucellosis cases tested at the National Animal and Plant Health Laboratory (NAPHL) between 2015 and 2019. Seropositivity was determined using the Rose Bengal Plate Test (RBPT). Spatio-temporal trends were analyzed using negative binomial regression and the Cochran–Armitage trend test, while multivariable logistic regression assessed associations between seropositivity and age, gender, residence, and geographic zone. Spatial distribution was visualized using ArcGIS and QGIS. Overall, RBPT seropositivity was 31.5%. Adolescents aged 11–18 years had 1.86 times higher odds of seropositivity compared to adults 19–40 years, while older adults (61–80 years) had reduced odds (OR = 0.56). Male participants (OR = 1.66) and rural residents (OR = 2.30) were at elevated risk. Regional analysis showed significantly higher incidence in Maekel (IRR = 5.02), Northern Red Sea (IRR = 2.85), and Debub (IRR = 1.97) compared to Anseba. Temporal analysis indicated a rising trend over the five years (IRR = 1.69 per year). Spatial patterns revealed heterogeneous sub-regional clustering across Eritrea. Human brucellosis in Eritrea exhibits pronounced demographic and geographic disparities, with adolescents, males, and rural residents bearing a higher risk. The findings highlight the importance of targeted surveillance and intervention strategies that focus on high-risk populations and regions to reduce infections and guide public health control efforts.