Development of an indirect ELISA for the detection of duck circovirus infection in duck flocks.

Infection with duck circovirus (DuCV) is associated with growth retardation and developmental problems in farmed ducks. To detect DuCV-specific antibody in duck serum, an indirect enzyme-linked immunosorbent assay (iELISA) method was developed using the recombinant capsid protein antigen prepared by cloning the cap (Cap) gene of DuCV FJ0601 strain into pET-32a (+) vector and expressed in Escherichia coli. Using the optimized iELISA method, DuCV-specific antibodies were detected in 157 (12.96%) of 1211 samples obtained from 17 (89.47%) of 19 meat duck flocks aged from 25 to 40 days and in 89 (22.08%) of 403 samples obtained from 9 (75%) of 12 breeder flocks aged from 14 to 61 weeks. These results indicated that the iELISA method is useful for serological diagnosis of DuCV infection and epidemiological investigation.