BRUCELLA-SUIS BIOTYPE 2 INFECTION OF WILD BOARS (SUS-SCROFA) IN BELGIUM

We describe the first case of enzootic Brucella suis biotype 2 brucellosis in wild swine (sus scrofa) in Europe where the disease seems to be enzootic in hares (lepus capensis). 13 Brucella suis biotype 2 strains were isolated from 141 samples (9,2 %). The serological diagnosis of brucellosis is still problematic in swine. In our study the slow agglutination test was found unsatisfactory. The plate agglutination test and the complement fixation test are found satisfactory, at the population level, if used in parallel and if the sample size is sufficient. We propose the use of an ELISA detecting all bacteriological positive animals. This test can be used on poor quality serum that can not be screened with classical tests. 39 % of the sera are classified positive with the ELISA. According to the biology of the Brucella suis biotype 2 infection in swine (self-limiting disease) and to the excellent specificity of this test in domestic pigs, our results suggest that there is a heavy circulation of this bacteria. The contamination of cattle by direct or indirect contact with infected wild swine or hares might be possible. Therefore, the implication of Brucella suis biotype 2 beside Yersinia enterocolitica 0:9 in the occurence of positive serology in brucellosis screening tests in cattle is discussed.