Vet. Res. 34 (2003) 297-305
DOI: 10.1051/vetres:2003005

Evaluation of a modified Rose Bengal test and an indirect Enzyme-Linked Immunosorbent Assay for the diagnosis of Brucella melitensis infection in sheep

Ana Cristina Ferreira^a, Regina Cardoso^a, Isabel Travassos Dias^a, Isabel Mariano^b, Ana Belo^c, Isabel Rolão Preto^c, António Manteigas^c, António Pina Fonseca^c and Maria Inácia Corrêa De Sá<sup>a

a</sup>  Laboratório Nacional de Investigação Veterinária (LNIV), Estrada de Benfica, 701,1549-011 Lisboa, Portugal
^b  Laboratório Veterinário de Montemor-o-Novo- COPRAPEC, 7050 Montemor-O-Novo, Portugal
^c  Direcção Regional de Agricultura da Beira Interior (DRABI), 6001 Castelo Branco, Portugal

(Received 9 August 2002; accepted 9 December 2002)

Abstract
A modified Rose Bengal test (mRB) and an indirect ELISA (iELISA) with Protein G as the conjugate, were evaluated for the diagnosis of Brucella melitensis infection in unvaccinated sheep with a known bacteriological status, and their diagnostic efficacy was compared with that of the standard Rose Bengal (RB) and Complement Fixation (CF) tests used in the current eradication campaign in EU countries. All tests showed 100% specificity when testing the sera from 212 Brucella-free sheep. When testing the sera from 219 Brucella melitensis culture-positive sheep, both the mRB and iELISA tests were more sensitive (98.6% and 96.8%, respectively) than the RB and CF tests (95.0% and 92.7%, respectively). These results were similar when testing the sera from 181 animals belonging to infected flocks but found bacteriologically negative, suggesting that the mRB or iELISA tests could advantageously replace the current RB procedure used as the screening test.

Key words: sheep / Brucella melitensis / serological diagnosis / modified rose bengal test / indirect ELISA

Correspondence and reprints: Maria Inácia Corrêa De Sá Tel.: (351) 217115223; fax: (351) 217115383
    e-mail: inacia.sa@lniv.min-agricultura.pt

© INRA, EDP Sciences 2003