health concern and economic importance worldwide, especially in Mediterranean countries (Munir et al., 2010). The disease is caused by aerobic, Gram-negative bacteria of the genus Brucella. The disease causing abortions, fetal death, genital infections and sterility (Probert et al., 2004). The transmission of the disease is by direct or indirect contact with infective execrators. They are shed in large numbers in the animal urine, milk, placental and other fluids (Otlu et al., 2006; Zvizdic et al., 2006).
Among the different species of genus Brucella, B. aboruts is the common strain infecting cattle all over the world while B. melitensis is affecting mainly sheep, goats and also other species (Alton, 1990). Cattle Brucellosis is usually caused by B. abortus biovars and occasionally by B. melitensis (OIE, 2008). In Egypt, starting from 1998 B. melitensis was reported to be the common strain isolated from cattle as reported by Shalaby et al.,(2003). Diagnosis of Brucellosis is based on isolation of the organism from infected animals but this is a cumbersome and time consuming task, due to the fact that these fastidious organisms grow slowly on primary isolation (Meyer, 1981). Moreover, it is not possible to isolate Brucella every time, even from infected individuals. Therefore, assessment of antibody response employing serological test plays a major role in the routine diagnosis of Brucellosis and supported where appropriate by bacteriological examination (Alton et al., 1988). The routine identification and differentiation of Brucella species is based on phenotypic traits, but it is …