An enzyme-linked immunosorbent assay for serodiagnosis of coccidiosis in chickens: use of a single serum dilution.

A simplified enzyme-linked immunosorbent assay (ELISA) was used to survey broiler chickens for coccidial infection. With an antigen derived from Eimeria tenella oocysts and a single serum dilution of 1:100, the absorbance values were directly used for the evaluation of antibody levels. When the detection level, determined with sera from specific-pathogen-free chickens, was used as the negative standard, randomly selected sera from broiler chickens essentially were negative. Sera were periodically collected from two flocks of commercial broilers reared under medication, and their ELISA titers were compared with their excretion of oocysts. When the oocyst isolation rate indicated that infection was severe, a substantial number of chickens showed high absorbance values in ELISA. These results indicate that coccidial infections in the field can be detected serologically with ELISA.