This study was conducted on dairy farms in Gharbia governorate, Egypt from January to December 2018. 240 dairy farms were included, and 3775 serum sample were collected for serological tests. 25 farms (10.42) were positive for brucellosis, 132 serum sample were positive by serological test classified according to the productive stage of animals as 121/3000 (4.033%), 8/600 (1.33%) and 2/175 (1.142%) in cows, heifers and bulls, respectively. The culturing and PCR confirmation results indicated that Brucella melitensis biovar 3 was the dominant strain in the tested dairy farms. The spatial distribution of positive cases indicated that districts of Samnood, Kfr-Elzyat and Basion had the highest rate of positive cases (6.35%, 4.67% and 3.57%, respectively), yet El-Santa, Zefta and El-Mahla El-Kobra districts showed the lowest rates (1.49%, 2.3% and 2.89%, respectively). The obtained result proved that brucellosis is endemic in Gharbia governorate and good control program should be conducted to eradicate the disease.

The current study was applied from January to December 2019 to determine and identify the prevalence rate of bovine brucellosis and its correlated risk factors in dairy herds in Nile delta, Egypt. The study populations comprised of 300 dairy farms which including 4000 dairy cattle. Estimated results showed that, the prevalence of brucellosis in dairy cattle was 6.05 % that depended on the result of CFT. The univariate statistical analysis revealed that positive cases of brucellosis was clearly higher in cattle housed under the intensive management system, and animals in the extensive management system had lower prevalence (P <0.001). Moreover, there was a statistically correlation between brucellosis and the age of animals (P < 0.01) but correlation was weak with the number of labor (P > 0.05). Significant increasing of positive cases was parallel with the increasing of the size of herd (P < 0.05). Sero-positivity to brucellosis was significantly correlated with history of abortions or stillbirths. The results estimated that brucellosis is endemic and widely distributed disease in Nile delta, Egypt.