Campylobacter fetus diagnosis: direct immunofluorescence comparing chicken IgY and rabbit IgG conjugates

In Argentina Bovine Genital Campylobacteriosis is routinely diagnosed by direct immunofluorescence test. Generally, the hyperimmune sera used for this test are obtained from rabbits and less often from goats. In this work, a chicken egg yolk immunoglobulin (IgY) extract was conjugated and its ability to detect campylobacters with the regular conjugate prepared with rabbit sera was comparatively evaluated. Both conjugates were independently evaluated by two laboratories, named "Azul" (Lab A) and "Balcarce" (Lab B). Animals were immunised with formalin inactivated Campylobacter (C.) fetus cells. Chicken IgY and rabbit IgG were conjugated with fluorescein isothiocyanate and used to comparatively examine strains of C. fetus subspp., other Campylobacter spp. and different bacterial species. Both conjugates had a high percentage rate of detection for C. fetus. IgY had less background due to unspecific fluorescence than IgG. IgY is a cheap, bloodless and very productive method. IgY can replace mammal immunoglobulins for C. fetus diagnosis.