Brucellosis 2003 proceedings - PHIDIAS

Short Oral Communications
Diagnosis in animal brucellosis
herds have to be routinely tested for at least 5 years. Besides that, the EU prescribes
notification of abortions and subsequent serological testing. False positive results of
serological test are a major problem in countries free from brucellosis. Because the
positive predictive value of a serological test in a population depends on the
prevalence of the disease, this problem will increase when the prevalence
decreases. By definition, in a free population, the positive predictive value will be
zero, meaning that better tests with higher specificities need to be developed and
validated. Since the early nineties, a significant increase of the number of FPR’s
have been reported, especially in Belgium and France. Serological cross reactivity
has been described with Yersinea enterocolitica O:9 as well as other gram negative
bacteria (Godfroid et al, 2002). To circumvent these cross reactivities, much effort
have been put in the development of tests based on Brucella specific (cellular)
antigens. The main problem thus far is the lack of sensitivity of these tests.
The aim of this project is to develop a new serological test which can be used
as conformation test following positive results in the tests prescribed by the EU.
Therefore, we constructed a genomic library of Brucella abortus strain 99. This library
was screened with a highly positive Brucella serum (serum 2427) in order to identify
cellular antigens reactive with this serum. In a first attempt, using the commercially
available TripleX system (Clontech), we found a set of cellular antigens, most of
which were previously described in the literature; i.e. BP26 (Zygmunt et al., 2002),
HtrA (Roop et al., 1994) and dimethyl-ribityl-lumazine (DMRL; Hemmen et al., 1995).
Because of this overlap, and due to some problems we and others encountered
using the TripleX system, we decided to construct and screen a new library
(ZapExpress; Stratagene), this time using two different Brucella field strains, a
biotype 1 as well as a biotype 2 strain. In this screening we found, among the
antigens described above, several new potential candidates which are currently
being tested.
DO6- COMPARISON OF ROSE BENGAL IN ANALOGY OF 1:3 WITH SERUM
AND ROSE BENGAL IN ANALOGY OF 1:1 WITH SERUM INTERPRETED IN
SERIES WITH COMPLEMENT FIXATION TEST AS CONFIRMATORY TEST FOR
THE DETECTION OF INFECTED SHEEP AND GOAT FLOCKS WITH Brucella
melitensis. A FOUR-MONTH FIELD TRIAL DURING THE CYPRUS
BRUCELLOSIS TEST AND SLAUGHTER ERADICATION PROGRAM.
M. V. Liapi 1 , I. G. Ioannou 1 , M. Papaprodromou 1 . (1) Veterinary Laboratories Department, Cyprus
Veterinary Services, Nicosia, Cyprus.
Rose Bengal antigen in analogy 1:3 (RB 1:3) with serum is recommended as
more sensitive compared to the classic Rose Bengal (Rose Bengal
antigen/serum=1:1, RB 1:1) for use in sheep and goats (Veterinary Record, 1994,
134, 415-420).
During the application of Cyprus Brucellosis eradication program, a four-month
trial was performed to compare the RB 1:1 with the more sensitive RB 1:3 as flock
screening tests. Blood samples from 50 animals per flock from two thousand two
hundred fifteen (2215) flocks were collected and examined using RB 1:3. All RB 1:3
positive (showing any degree of agglutination) samples were examined using RB 1:1
and complement fixation test (CFT). Samples showing any degree of agglutination in
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Brucellosis 2003 International Research Conference