Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Norovirus negatively stained with PTA. This small virus is from the stool specimen of a patient with ‘winter vomiting disease’. Note the fuzzy or ragged-edged morphology of this virus and the presence of some empty virions. Norovirus is 30–35 nm in diameter.
