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Microbiological and Chemical Exposure Assessment

Norwalk virus (norovirus)

Norwalk virus image

Photo Credit: F.P. Williams, U.S. EPA

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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

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