History
The first major outbreak of human norovirus occurred in 1968 in Norwalk, Ohio, USA. During this outbreak, 50% of elementary school students in Norwalk manifested the common symptoms associated with gastroenteritis.¹ Scientists would not become aware of the cause of the outbreak until 1972 using electron microscopy to visualize the virus particles.² Throughout the 1990’s scientists conducted more detailed studies on the Norwalk virus’ genes and proteins. This research led to the determination that the virus belonged to a group of human viruses now known as noroviruses.³ Norovirus continues to be problematic as, “infected people produce a lot of the virus, but it may take as few as 20 individual virus particles to make someone sick”.² Additionally, researchers studying norovirus are, “faced [with] many difficulties, including genetic/antigenic diversity, limited knowledge on NoV immunology and viral cycle, lack of permissive cell line for cultivation and lack of a widely available and successful animal model.”⁴ While symptoms of norovirus generally last one to three days⁵, norovirus in immunocompromised patients can become a chronic infection, with virus persisting for weeks and even years.⁶. More research is needed to better understand norovirus and to aid in the development of treatment options and a vaccine. The Norovirus Foundation aims to raise awareness and support research and biomedical advancement towards finding effective therapeutic and curative strategies that benefit vulnerable populations affected by norovirus.
Citations
Norovirus Fact Sheet
Worldwide, norovirus is estimated to be the most common cause of acute gastroenteritis (inflammation of the stomach or intestines or both).
New norovirus strains emerge about every 2 to 4 years.
Noroviruses are difficult to wipe out because they can withstand hot and cold temperatures as well as most disinfectants.
Norovirus is the leading cause of illness and outbreaks from contaminated food in the United States.
Norovirus is estimated to cost $60 billion annually due to complication sand lost productivity.
Most norovirus outbreaks occur in food service settings like restaurants. Infected food workers are frequently the source of the outbreaks, often by touching ready-to-eat foods.
Each year, 1 in 6 Americans get sick from eating contaminated food.
Worldwide, norovirus is responsible for 685 million episodes of gastroenteritis annually, with 200 million of these cases among children younger than age 5 years.
Norovirus outbreaks can occur from foods such as oysters, fruits and vegetables that are contaminated at their source.
Image - 3-D structure of norovirus polymerase (cartoon) in complex with viral RNA ( stick and tubes) and Mg2+ ions (sphere)
Dharmesh Patel, PhD, Department of Pediatrics, Emory University