The degree of protection given by living vaccines against experimental infection with Brucella melitensis in goats.

It has been shown by a number of workers that Brucella melitensis Rev. 1 vaccine confers good protection against infection with Br. melitensis in sheep and goats. Although Br. abortus strain 19 vaccine is widely used in some countries to protect sheep, it has not been evaluated for caprine brucellosis. The purpose of the experiment reported in this paper was to determine and compare the degree of protection given by living vaccines prepared from Rev. 1 and strain 19 and by a non-agglutinogenic strain of Br. melitensis against graded, experimental challenge in goats.Under the conditions of the experiment, it was clearly shown that the Rev. 1 vaccine gave much better protection than either strain 19 or the non-agglutinogenic strain.There was no relationship between antibody response to vaccination and immunity but there was some correlation between the allergic response and immunity; it is suggested that the allergic response might be used as an initial screening test for evaluating Brucella vaccines.