Development of an indirect ELISA method for detection of antibody to duck circovirus

Duck circovirus is a newly emerged virus that was commonly associated with damage of lymphoreticular tissues and it is the smallest virus isolated from duck so far.There is no commercial ELISA kit available for duck circovirus(DuCV)antibody detection.In order to survey the serum epidemiological characteristic of DuCV,an indirect ELISA was developed based on the recombinant full-length Cap protein of DuCV in the present study.The recombinant Cap protein was expressed in E.coli expression system and purified by His Bind affinity chromatography.The recombinant Cap based ELISA was evaluated by examining a panel of 30 DuCV antibody negative and 16 DuCV antibody positive sera.Cross-reactivity assay showed that this assay was DuCV antibody specific.Repeatability tests revealed that the coefficients of variation of positive sera within and between runs were less than 10%.Using the established indirect ELISA,DuCV-specific antibodies were detected in 38(26.7%)of 142 samples obtained from 8 of 12 duck flocks from Jiangsu Province.This ELISA is simpler to produce and perform,suitable for large scale surveys of DuCV infection at low cost.