University of Tabriz Journal of Zoonotic Diseases 2476-535X 10 1 2026 01 01 Concurrent seroprevalence of the zoonotic diseases Q fever and brucellosis and their association with abortion in small ruminants from Medea province, northern Algeria 1114 1122 21074 10.22034/jzd.2026.21074 EN Salah Eddine Merdja Institute of Veterinary Sciences, University of Blida 1, Blida, Algeria Ali Dahmani Institute of Veterinary Sciences, University of Blida 1, Blida, Algeria Hamza Khaled Institute of Veterinary Sciences, University of Blida 1, Blida, Algeria Abdallah Bouyoucef Institute of Veterinary Sciences, University of Blida 1, Blida, Algeria Journal Article 2025 11 25 Q fever and brucellosis are two important zoonotic diseases. They affect reproduction in small ruminants and have significant consequences for public health and the economy. This study aimed to investigate the presence of exposure to zoonotic pathogens, <em>Coxiella burnetii</em> and <em>Brucella</em> species, in small ruminants and to determine their seropositivity in the province of Medea, Northern Algeria. A total of 157 blood samples were collected from 17 flocks in Medea province from unvaccinated small ruminants. Only animals more than six months of age and that had stayed more than one year in the herd were sampled. Two indirect ELISAs were used to detect antibodies against <em>C. burnetii</em> and <em>Brucella spp.</em> This survey was conducted in sheep and goat flocks, indicating that antibodies were detected in 16.5% (95% CI, 10.8 - 22.4) for <em>C. burnetii</em> and 7.6% (95% CI, 3.5 - 11.8) for <em>Brucella spp.</em> This study provided seroprevalence data for two major zoonoses, Q fever and brucellosis, using the same small ruminant samples. Our results showed that <em>C. burnetii</em> infection was higher than that of <em>Brucella spp.</em> infection in small ruminants in this area. An intriguing result of the present study shows that co-infection was detected in the farm P in the Medea province. These findings are essential to implement a One Health approach to assess the incidence of these zoonoses in humans and to study transmission routes, particularly among people in direct contact with these animals. https://jzd.tabrizu.ac.ir/article_21074_5c18aab2d52fe22ef6ba76978918d21e.pdf