Brucellosis 2003 proceedings - PHIDIAS

Poster Session
agglutination (SAT), 2-mercaptoethanol (2-ME), Complement fixation (FC), indirect
and competitive enzyme immunoassay (ELISA) and fluorescence polarization assay
(FPA) (J. Wild. Dis. 2001; 37:89 -100). Six of 160 animals were positive by at least 3
tests (BPA, CELISA and FPA). These 6 positive animals were elephant seals. All
other animals were negative to all tests performed. We found 2 non-expected
reactions, first CF showed high anticomplementary activity in most of the cases
(149/160). Second 2-ME showed higher titers than Wright in 26 cases. Furthermore,
the IELISA was negative for all these animals. We did not have enough positive
samples to fully evaluate these tests, however it can be suggested that either FC,
Wright, 2ME and IELISA are not suitable tests to evaluate brucellosis in pinnipeds.
Our results show that elephant seals from the coast of Argentina have been exposed
to antigen of Brucella sp. The good performance of FPA and CELISA indicate that
these tests should be validated for the detection of brucellosis in pinnipeds.
59- EFFICACY OF DIFFERENT ANTIGENS AND TESTS FOR THE
SEROLOGICAL DIAGNOSIS OF BRUCELLOSIS IN CATTLE IN A CONTEXT OF
FALSE POSITIVE REACTIONS DUE TO Yersinia enterocolitica O:9.
P. M. Muñoz 1 , C. M. Marín 1 , R. Díaz 2 , I. Moriyón 2 , B. Garin-Bastuji 3 and J. M. Blasco 1 . (1) Unidad de
Sanidad Animal. SIA/DGA, Zaragoza, Spain. (2) Departamento de Microbiología, Universidad de
Navarra, Pamplona, Spain. (3) Brucellosis Reference Laboratory, AFSSA, Maisons Alfort, France.
Serological tests using whole smooth cells or smooth lipopolysaccharide (S-
LPS) as antigens are the most widely used for diagnosing Brucellosis in cattle, but
are susceptible to false positive serological reactions (FPSR) when cattle are or have
been recently infected by Yersinia enterocolitica O:9. The best strategy known to
differentiate Brucella from Y. enterocolitica O:9 infections is based on the use of
cytosolic Brucella proteins in a skin test. This test is cumbersome and very expensive
and researching simple and cheaper diagnostic tests is advisable. This work
compared the efficacy of several antigens and tests for the serological differentiation
of Brucella from Y. enterocolitica O:9 infections in cattle. None of the Brucella
homologous S-LPS, polysaccharide (native hapten, O-chain and poly B), proteins
(cytosolic and BP26 recombinant protein) and rough extracts (B. ovis hot saline or B.
abortus per A R-LPS) or heterologous antigens (E. hermanni S-LPS and O.
intermedium cytosolic proteins) tested in an indirect ELISA (iELISA) was able to fully
differentiate FPSR from responses due to brucellosis. An iELISA/S-LPS using 3M
KSCN as chaotropic reagent improved the specificity of the iELISA/S-LPS alone for
such differentiation. A competitive ELISA using Mab M84 of C/Y specificity as
competing reagent was not useful for the same purpose. By contrast, gel
precipitation tests with Brucella native hapten polysaccharide or cytosolic proteins
were useful (about 90% sensitivity and 100% specificity) for identifying Brucella
infected animals in a FPSR context. These tests could be used as confirmatory tests
at the herd level in areas with no obvious risk of Brucella infection and where false
positive reactions due to Y. enterocolitica O:9 are observed.
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Brucellosis 2003 International Research Conference