Profiling Norovirus

Norovirus wreaks havoc among captive audiences – cruise ships, hotels, restaurants and nursing homes.

Some history

The syndrome known as “acute non-bacterial infectious gastroenteritis was known to physicians and epidemiologists since the 1940s. In 1972, Norwalk virus – now called Norovirus – was recognized as a significant cause of this syndrome.

What is Norovirus, and where is its natural habitat?

Humans are the natural hosts of Norovirus. Transmission of the virus through animals has been suggested as a possibility, but not confirmed.

How is Norovirus transmitted? What is the incubation period of the illness?

Norovirus is transmitted, directly or indirectly, via the fecal-oral route. The virus is extremely hardy and can survive for days on dry surfaces such as furniture, handrails, and other contact surfaces. The virus is spread through the vomit or feces of an infected individual, or via contaminated food or water. An outbreak can expand rapidly, as the incubation period is usually only 24-48 hours.

What are the symptoms of Norovirus gastroenteritis?

Symptoms include nausea, vomiting and copious watery diarrhea.

What is the prognosis of Norovirus gastroenteritis?

Symptoms typically are self-limiting in otherwise healthy adults, lasting 24 to 60 hours. Norovirus gastroenteritis can cause severe dehydration in the elderly or the very young. Approximately 1% of victims require hospitalization.

What foods carry Norovirus?

Norovirus can be present on any surface (including food utensils) or in any food that has been contacted by an infected individual, such as a food handler. The virus does not multiply outside of its human hosts, but as few as 10 virus particles are enough to cause infection.

How can people protect themselves from Norovirus?

• Paying attention to food recall announcements and immediately discard any recalled food or return it to the store.
• Pay close attention to personal hygiene, especially when caring for an individual who is suffering from gastroenteritis.
• If you are suffering from gastroenteritis, do not prepare food for others or serve food.
• Avoid self-serve buffets, especially on cruise ships.
• Wash your hands thoroughly after touching surfaces in public places, before eating, and before touching your face. Be aware that some objects (e.g., gambling chips in casinos) have been handled by many people, any of whom may be harboring the virus.

For more information on Norovirus and other food-borne pathogens, visit the CDC website or read Food Safety: Old Habits, New Perspectives.