Probing the structure of the SARS coronavirus using scanning electron microscopy.

A novel coronavirus, SARS-CoV, has been confirmed to be the aetiological agent of SARS. Transmission electron microscope (TEM) images played an important role in initial identification of the pathogen. In order to obtain greater morphological detail of SARS-CoV than could be obtained by TEM, we used ultra-high resolution scanning electron microscopy (SEM) to image the virus particles. We show here the three-dimensional appearance of SARS-CoV. Enhanced detail of the ultrastructure reveals the trimeric structure of the 10-20 nm spikes on the virion surface. These results contribute to characterization of the SARS agent and development of new antiviral strategies.