Morphology of A/WSN influenza virus-infected chick embryo cells.

A/WSN (H0N1) influenza virus-infected chick embryo cells (CEC) attained a swollen central region 4 hours post infection (p.i.), different from the elongated uninfected cell. From 6 hours p.i. of CEC an increasing number of approximately 100-120 nm, round protrusions were observed by scanning and transmission electron microscopy on the cell membrane, which was smooth on the uninfected cell. At 48 hours p.i. a great number of protrusions were observed on the cell; in addition, there were a number of holes or invaginations in the membranes of the infected cells indicating cell destruction.