Brucellosis 2003 proceedings - PHIDIAS

Keynote Lectures
Routine biochemical and haematological laboratory tests show variable and
overlapping results with many other diseases. The Brucella-specific tests are the
mainstay in laboratory diagnosis of brucellosis. These include culture, slide or tube
agglutination, indirect Coombs’, ELISA, IFA, and molecular techniques e.g. PCR.
Different types of antigen preparations have been utilized in detecting Ig classes and
subclasses seeking reliable diagnostic and prognostic assays and markers. ELISA
proved to be the test of choice especially in complicated and chronic cases. So far,
the key approach in determining prognosis and relapse is a sequential follow-up of
patients using serological tests. Discrimination between active and inactive stages
can be very difficult, however, the use of certain antigens e.g anti Brucella
cytoplasmic or membranous protein antibodies in ELISA seems useful. Molecular
tests were shown to have a promising role in diagnosis, however, their potential
value in patient follow-up and in distinguishing among different disease forms,
remains to be determined. Knowledge about the advantages, disadvantages and
limitations of these tests are essential for the proper interpretation of results, in
relation to the history and clinical presentation of patients under investigation.
DEVELOPMENT AND VALIDATION OF DIAGNOSTIC TOOLS AND TYPING
METHODS FOR THE CERTIFICATION OF THE ABSENCE OF BOVINE
BRUCELLOSIS IN BELGIUM.
J. Godfroid. Veterinary and Agrochemical Research Center, Brussels, Belgium.
In the beginning of the nineties, the prevalence rate of bovine brucellosis was
very low in Belgium, although bovine brucellosis was not eradicated. This
epidemiological situation allowed us to describe a new phenomenon: the emergence
of “False Positive Serological Reactions” (FPSR) in bovine brucellosis screening
tests. The most likely hypothesis to explain this phenomenon (but maybe not the only
one) is a Yersinia enterocolitica O:9 infection. In parallel, we described for the first
time, a Brucella suis biotype 2 enzootic brucellosis in wild boars (Sus scrofa) in
Western Europe.
Therefore, new diagnostic tools had to be developed in order to differentiate
beyond any doubt cattle infected by Brucella abortus, Brucella suis or Yersinia
enterocolitica O:9. Our work allowed us to validate, under experimental conditions,
the brucellosis skin test and the IFN-γ assay as bovine brucellosis diagnostic tools. A
testing strategy integrating these new tools has been successfully implemented in the
field in Belgium. This work has led to the incorporation of the brucellosis skin test in
the new Directive 432/64/CEE that deals with living animals movements within the
European Union.
Recently, our knowledge of the ecological niche of Brucella has been
extended to marine mammals. It has been shown that these Brucella represent a
new potential source of infection for both domestic animals and humans. Studies on
the molecular typing of marine mammal Brucella reinforce the proposal of adding two
new species in the genus Brucella: Brucella cetaceae (infection in cetacean) and
Brucella pinnipediae (infection in pinnipeds).
Brucellosis 2003 International Research Conference
39