Identification of CHGD-01 isolate by optical microscopy, IFA assay and electron microscopy. (a) Mock-infected Vero cells. (b) CPE in Vero cells infected with PEDV-CHGD-01 showing syncytia and multiple nuclei. (c) IFA in non-infected Vero cells. (d) IFA in CHGD-01 isolate-infected Vero cells. Original magnification × 200. (e) Morphology of CHGD-01 isolate under electron microscopy (negatively stained); bar = 200 nm.