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Norwalk virus (norovirus)
Photo Credit: F.P. Williams, U.S. EPA
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
Photo Credit: These images are in the public domain and are thus free of any copyright restrictions. For public domain images, permission is not required for their use but we do ask that you credit the EPA and the contributors (found in the Photo Credit line) whenever an image is used in any publicly distributed media.
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