Brucellosis among exported livestock from the Horn of Africa to Yemen: Seroprevalence study associated with risk factors

Abstract

The international trade of livestock plays a significant role in the global dissemination of transboundary animal diseases and associated crisis risks. Brucellosis, a silent zoonotic transboundary disease, affects most live- stock species. This study investigated the prevalence of brucellosis among camels, cattle, sheep, and goats exported from Djibouti and Somalia to Yemen. From April 2024 to April 2025, 1500 blood samples were tested using WOAH-officially recognized sero agglutination techniques. Overall, 34 of 1500 samples (2.26%) tested positive for Brucella. Our analysis revealed significant differences in brucellosis positivity across animal types, age groups, and origins. Cattle showed the highest positivity rate, with 24 of 375 samples (6.4%). In contrast, sheep had 6 positive samples (1.6%), goats had 4 (1.1%), and camels had no positive samples (0%). When examining age, the older group (2-3 years) exhibited the highest prevalence, with 17 of 408 samples (4.2%). The positivity rates varied slightly across seasons, peaking in spring (3%) and autumn (2.6%), with lower rates in summer (2.2%) and winter (1.3%). Regarding origin, the Hirshabella district recorded the highest positivity in 13 of 125 samples (10.4%). This was followed by Southwest Somalia (5.5%) and Jubaland (4.4%). This study represents the first reported index of brucellosis among animals exported to Yemen, underscoring a significant risk, particularly for cattle and older animals. These findings highlight the urgent need for comprehensive epi- demiological investigations to provide policymakers with the data necessary to formulate effective regulations, thereby reducing the spread of this transboundary animal disease.