Robardet, E.3; Andrieu, S.3; Rasmussen, Thomas Bruun1; Dobrostana, M.4; Horton, D. L.5; Hostnik, P.6; Jaceviciene, I.7; Juhasz, T.8; Müller, T.9; F. Mutinelli10; Servat, A.3; M. Smreczak10; Vanek, E.11; S. Vázquez-Morón10; Cliquet, F.3
1 National Veterinary Institute, Technical University of Denmark2 Section for Virology, National Veterinary Institute, Technical University of Denmark3 French Agency for Food, Environmental and Occupational Health & Safety4 Institute of Food Safety, Animal Health and Environment5 Animal Health and Veterinary Laboratories Agency6 National Veterinary Institute7 National Food and Veterinary Risk Assessment Institute8 Central Veterinary Institute9 Friedrich Loeffler Institute10 Instituto Zooprofilattico Sperimentale delle Venezie11 Austrian Agency for Health and Food Safety
Twelve National Reference Laboratories (NRLs) for rabies have undertaken a comparative assay to assess the comparison of fluorescent antibody test (FAT) results using five coded commercial anti-rabies conjugates (Biorad, Bioveta, Fujirebio, Millipore, and SIFIN conjugates). Homogenized positive brain tissues infected with various lyssavirus species as well as negative samples were analyzed blindly using a standardized FAT procedure. Conjugates B, C, D, and E were found to be significantly more effective than conjugate A for GS7 (French RABV) diluted samples (1/8 and 1/100) while the frequency of concordant results of conjugates C and D differ significantly from conjugates A, B and E for CVS 27. For detection of EBLV-1 strains, conjugates C and D also presented a significantly lower frequency of discordant results compared to conjugates A, B and E. Conjugates B, C and D were found to be significantly more effective than conjugates E and A for EBLV-2 and ABLV samples. In view of these results, conjugates C and D set themselves apart from the others and appeared as the most effective of this 5-panel conjugates. This study clearly demonstrates that the variability of conjugates used by National Reference Laboratories can potentially lead to discordant results and influence assay sensitivity. In case of false negative results this could have a dramatic impact if the animal under investigation is responsible for human exposure. To avoid such situations, confirmatory tests should be implemented.
Journal of Virological Methods, 2013, Vol 191, p. 88-94