Seroprevalence and molecular investigation of camel brucellosis in Egypt with emphasis on potential risk factors

Brucellosis is a significant zoonotic bacterial disease that affects both humans and animals, resulting in severe economic losses. The current study aimed to report the seroprevalence of brucellosis in dromedary camels in Egypt and to identify the potential risk factors associated with the disease. A total of 618 serum samples were collected from apparently healthy animals in Al-Bahr Al-Ahmar and Giza governorates, Egypt, from January 2022 to June 2023. Six milk samples were collected from seropositive animals to confirm the diagnosis of brucellosis using polymerase chain reaction (PCR). The serum samples were analyzed using the rose bengal plate test (RBPT) and indirect ELISA (iELISA). The seroprevalence rates were 26.8% (166/618) and 18.3% (113/618) using RBPT and iELISA, respectively. Of the six milk samples tested for brucellosis, five were positive (two for Brucella abortus and three for Brucella melitensis), while one showed negative results, and Brucella suis was not detected. Among the risk factors analyzed in our study, history of abortion, herd size, and mixed rearing with ruminants were statistically significant (p-value≤0.05). In conclusion, B. abortus and B. melitensis are circulating in the camel populations in Egypt. ELISA was more sensitive in the serodiagnosis of camel Brucella antibodies compared to RBPT among camel populations using serum samples. The study recommends that camels and ruminants should be raised separately, and more restrictive control measures should be considered for imported camels.