Coronaviruses derive their name from the fact that under electron microscopic examination, each virion is surrounded by a “corona,” or halo. This is due to the presence of viral spike peplomers emanating from each proteinaceous envelope.
An electron micrograph of a thin section of MERS-CoV, showing the spherical particles within the cytoplasm of an infected cell.
Source: Cynthia Goldsmith/Azaibi Tamin
Human serum antibodies react with MERS-CoV-infected Vero cells, indicating the patient has been infected with MERS-CoV.
Source: Jennifer L. Harcourt
MERS-CoV particles as seen by negative stain electron microscopy. Virions contain characteristic club-like projections emanating from the viral membrane.