Identification and Isolation of TGEV-HX. (A) Identification of five transmissible gastroenteritis virus (TGEV) samples by PCR. (B) Cytopathic effect (CPE) induced by TGEV HX in the PK-15 cell line. (C) control (uninfected) PK-15 cells. (D) Electron micrograph of the purified isolate negatively stained with 2% phosphotungstic acid. The scale bar represents 500 nm.