Secondary envelopment and virus egress. Envelopment of EHV-1 (A), HSV-1 (B), ILTV (C), and PrV (D) at membranes of the trans-Golgi area. Particles of EHV-1 (E), HSV-1 (F), ILTV (G), and PrV (H) within Golgi vesicles are shown, as is egress of EHV-1 (I), HSV-1 (J), ILTV (K), and PrV (L) by fusion of vesicles with the plasma membrane. The bars represent 150 nm in panels A to K and 250 nm in panel L.