Microbiological and Chemical Exposure Assessment
Norwalk virus (norovirus)
Note the ill-defined somewhat lace-like appearance of individual virus particles. The virus particles of Norwalk and other SRSVs (Small Round Structured Viruses) exhibit a characteristic appearance that is distinct from the featureless appearance of poliovirus. It is also distinct from other small viruses such as astrovirus, and typical (non-SRSV) calicivirus. Viruses of the Norwalk type are now classified as noroviruses. Bar = 50 nanometers.
Source: Stool sample from an individual with gastroenteritis.
Method: Negative-stain Transmission Electron Microscopy