norwalk virus scott vasporycraig pritch october 4, 2005
Post on 21-Dec-2015
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Introduction to the Norwalk Virus
Norwalk – genus name for original Norwalk virus and other Norwalk-like viruses. Family Calicivirus.
Calicivirae found worldwide, infecting humans, primates, and cattle, among others.
Increasingly being recognized as leading cause of food borne illness.
History
Virus first identified in Norwalk, Ohio, 1973.
Noted to commonly be a problem on cruise ships.
Associated with contaminated food or water supplies.
Morphology
Nonenveloped capsid/nucleocapsid.
Icosahedral, 35-39 nm diameter
Picture: Norwalk virus, left and middle. Unspecified Calicivirus, right.
Genome Organization
ORF1 – polyprotein – similar to helicase, RNA polymerase of polio and RNA viruses
ORF2 – capsid protein
ORF3 – codes for protein of unknown function
Infection
Noroviruses found in stool and vomit of infected.
Very contagious – infection via eating contaminated food, contact with sick individual or contaminated surfaces.
Symptoms
Acute gastroenteritis. Illness begins suddenly, from 12-48 hours
after ingestion. Brief illness period.Very young, elderly, and those with
weakened immune systems may experience more severe symptoms.
Infectiousness may last up to 2 weeks, no evidence of long-term carriers.
Diagnosis
Electron MicroscopeRT-PCRELISA
Calicivirus is not easily studied. No efficient techniques have been developed to culture it in a lab setting.
References
• Büchen-Osmond, C. (Ed), (2003). 00.012. Caliciviridae. In: ICTVdB - The Universal Virus Database, version 3. ICTVdB Management, Columbia University, New York, NY, USA.
• CDC. accessed September 29, 2005. Norovirus. http://www.cdc.gov/ncidod/dvrd/revb/gastro/norovirus-qa.htm
• Directors of Health Promotion and Education. Accessed September 29, 2005. Norwalk Virus Infection. http://www.astdhpphe.org/infect/norwalk.html
• Microbiology Department, Mount Sinai Hospital. Accessed October 2, 2005. Norwalk and Noroviruses. http://microbiology.mtsinai.on.ca/bug/norwalk/nor-bug.shtml