THE IMPORTANCE OF BRUCELLIN ALGERIC SKIN TEST FOR DIAGNOSIS OF BOVINE BRUCELLOSIS

Abstract

Infection with Brucella results in the induction of both humoral andcellular immune responses. Humoral immune resposne is based on monitoringthe occurrence of specific antibodies against smooth lipopolysaccharide (S-LPS)of Brucella. However, in cattle, classical serological methods can detect antigenicdeterminants for other types of microorganisms (cross reactivity) such as Escherichiacoli 0:157, Yersinia enterocolitica 0:9, Salmonella urban, Pseudomonas malthopilia andPasteurella. The aim of our work was to determine the immunological responsebased on the use of standardized and purified allergen in which lypopolysaharid hasbeen removed and doesn’t induce humoral immune response. A total of 16 dairycattle previously tested positive using RBT (Rose Bengal test) and CFT (complementfixation test) were tested for confirmation with BST (brucelline skin test) accordingto the instructions of the producer. B. melitensis B115 (Synbiotics BrucellergeneOCB) was used in the test. 14 of 16 cattle reacted with skin thickening >1 mm after72 hours from the application of brucellin. 2 animals with no skin thickening orthickening <1mm also reacted negative in CFT. This outcome can be attributed tocross reactions with other antigens than Brucella that commonly occurs in RoseBengal test.Brucellin allergic skin test is not recommended as a standalone diagnostic toolbecause all infected animals do not react therefore this test cannot be recommendedas a self-sufficient diagnostic test or for the purpose of international trade.However, due to high specificity and adequate sensitivity at the herd level, it can berecommended for the control of herds in areas free of brucellosis.