Norovirus Research Paper

Introduction

Norovirus is one of the leading causes, if not the leading cause of gastroenteritis worldwide (6).

Transmission Norovirus is extremely contagious and is transmitted primarily via the fecal-oral route and is transmitted by way of fomites, consuming contaminated food or water, or contact with an infected person (2). It can also be transmitted if the vomit of an infected person becomes aerosolized (2). One study estimated that the average number of norovirus particles necessary to cause infection is as low as 0.5, meaning that of people who contracted a single norovirus virion, half will become infected (3). As of 2008, that is the lowest of any virus that has been studied (3). Norovirus is one of the few viruses that is transmitted mostly through contaminated food. This usually happens when an infected person fails to properly wash his or her hands after using the bathroom and before preparing food. Many people infected with norovirus are asymptomatic which increases the spread of the virus. Infected but asymptomatic food handlers have been the cause of several norovirus outbreaks (4). The virus can also build up inside filter feeding shellfish such as oysters, mussels, and clams if surrounding water becomes contaminated with human waste (5). A study performed in South Korea that collected shellfish and tested them for norovirus showed that it was present in approximately 27.9

Using genetic analysis, the virus has been further divided into many genogroups: GI, GII, GIII, GIV, and GV (8). Of the five genogroups only GI, GII, and GIV infect humans (8). Norovirus is a T=3 icosahedral and does not have an envelope (9). Its mass is approximately 56-76 kDaltons and its capsid diameter is anywhere from 23 to 38 nm (9,10). Its genome is linear and is approximately 7.3 to 8.3 kb