Application of biotechnology in the diagnosis and control of brucellosis in the Near East Region

Abstract

Although much information is available on the diagnosis and control of brucellosis, most of it is concerned with Brucella abortus in cattle. In contrast, no specific serological test for Brucella melitensis infection in small ruminants has been developed. Antigens prepared from Brucella abortus, as well as tests used for diagnosis of Brucella abortus infection in cattle, are also used for diagnosis of Brucella melitensis in small ruminants, buffaloes, camels, swine and other animals. Control policy for Brucella melitensis has not yet been established in all countries of the region, probably due to lack of information on the best methods. Moreover, little information exists on the efficacy of a mass vaccination strategy in small ruminants, regarding vaccine strain persistence in the host and its excretion in the milk of adult animals, or horizontal transfer in the field. In addition, recent data have suggested that Brucella melitensis may have evolved to more virulent strains which represent a higher risk for humans. It is suggested that a project should be financed to establish or develop a feasible regional brucellosis control programme, whose objectives will be: (i) to survey different animal species and evaluate the applicability of several serological and molecular biological techniques using specific diagnostics prepared by genetic engineering; (ii) to characterize bacteriological and genetic properties of Brucella isolates as well as the Brucella melitensis Rev. 1 vaccinal isolates recovered from different animals in various countries of the region and compare them to the standard Elberg strain. This will provide an insight into the mechanisms involved in the attenuation of the strain and its immune properties. This knowledge will be used to boost the immune protection conferred by conventional Brucella melitensis Rev. 1 vaccination, to develop new effective attenuated vaccine and/or to design subunit or DNA vaccines for ‘whole flock’ vaccination.