Vet. Res. 37 (2006) 623-632
DOI: 10.1051/vetres:2006023

Evaluation of a recombinant enzyme-linked immunosorbent assay for detecting Chlamydophila psittaci antibodies in turkey sera

Kristel Verminnen^a, Marnix Van Loock^b, Hafez Mohamed Hafez^c, Richard Ducatelle^d, Freddy Haesebrouck^d and Daisy Vanrompay<sup>a

a</sup>  Laboratory of Immunology and Animal Biotechnology, Department of Molecular Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, Ghent 9000, Belgium
^b  Laboratory of Immunology and Physiology of Domestic Animals, Faculty of Applied Bioscience and Engineering, KULeuven, Kasteelpark Arenberg 30, 3001 Leuven, Belgium
^c  Department of Veterinary Medicine, Institute of poultry Diseases, FUBerlin, Koserstr. 21, 14195 Berlin, Germany
^d  Department of Pathology, Bacteriology and Poultry Disease, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium

(Received 25 May 2005; accepted 16 February 2006; published online 16 May 2006)

Abstract - Chlamydophila psittaci (formerly Chlamydia psittaci) is one of the major pathogens associated with turkey respiratory disease. Devastating outbreaks with high mortality rates, similar to those of 1950 to 1970 in the USA occasionally occur, but respiratory signs without or with low mortality mostly characterize outbreaks now a day. Accurate diagnostic methods should be made available. The present study examined the sensitivity and specificity of a recombinant ELISA (rMOMP ELISA) for detecting Cp. psittaci major outer membrane specific antibodies in turkey sera. Test results were compared to those of immunoblotting and of a competitive ELISA (Chlamydia-psittaci-AK-EIA, Röhm Pharma, Germany) and an indirect ELISA (LPS/LGP) detecting antibodies to the lipopolysaccharide/lipoglycoprotein complex. The rMOMP ELISA was most sensitive as determined on serial dilutions of positive control sera originating from experimentally infected SPF turkeys. The competitive ELISA gave false positives since three negative controls reacted positive. For conventional sera, the sensitivities of the competitive ELISA, immunoblotting and the indirect ELISA were found to be 99.4, 93.1 and 82.2%, respectively, as compared to the rMOMP ELISA (100%). The specificities of the rMOMP ELISA, immunoblotting and the indirect ELISA were found to be 100% while the specificity of the competitive ELISA was only 2.7%. The rMOMP ELISA was chosen to compare the prevalence of chlamydiosis in 2002 with the one from 1992. In 2002, 188 on 200 (94%) turkey sera reacted positive compared to 175 on 200 (87.5%) in 1992 and like 10 years ago all examined farms were seropositive at slaughter. Interestingly, Belgian as well as French farms were seropositive.

Key words: Chlamydophila psittaci / antibody / recombinant ELISA / turkey

Corresponding author: Kristel Verminnen Kristel.Verminnen@UGent.be

© INRA, EDP Sciences 2006