Recently, it was stated in several news reports that, annually, 1 out of 6 Americans become ill from foodborne diseases, which equates to 48 million people.  Out of 48 million people sickened, 3000 will result in death (generally people with weakened immune systems, the very young or elderly).  Salmonella accounts for 28 percent of the deaths and 35 percent of hospitalizations.   Approximately, 90 percent of estimated illnesses, hospitalizations and deaths were due to; Salmonella, norovirus, toxoplasma, E.coli O157, Listeria, Campylobacter and Clostridium perfringens. Within the next few weeks on our blog each individually listed cause of foodborne illnesses will be described.  This week’s blog will be on Norovirus, which most people have experienced at one time or another within their lifetime.

NOROVIRUS:
Norovirus was formerly called Norwalk agent and most commonly called the “stomach flu” (a broad name that refers to gastric inflammation caused by a range of viruses and bacteria).  This causes about 90 percent of epidemic non-bacterial outbreaks of gastroenteritis around the world and causes a high percentage of foodborne outbreaks within the US.  The viruses are transmitted by faecally contaminated food or water, person-to-person contact (that is why hand washing is SO important), and via aerosolization of the virus, which causes the contamination of surfaces (another reason to wash your hands).  Interestingly, people with blood type O are more often infected, while blood types B and AB can confer partial protection against symptomatic infection. 

Outbreaks of the norovirus infection often occurs in closed or semi-closed communities, such as long-term care facilities, hospitals, schools, cruise ships and dormitories.  These infections spread rapidly either by person-to-person contact or through contaminated food.  Many norovirus outbreaks have been traced to food that was handled by one infected person.

How to inactivate? Either sufficient heating or by cleaning with chlorine-based disinfectants.

Symptoms: vomiting, diarrhea, abdominal pain and in some cases loss of taste, low grade fever, muscle aches and headaches may also occur.

Incubation period: Symptoms may appear 1 to 2 days after exposure. The principal symptom, gastroenteritis, develops between 24 and 48 hours after exposure and last for 24-60 hours.

References:
http://www.cdc.gov/media/pressrel/2010/r101215.html
http://en.wikipedia.org/wiki/Norovirus

 Next week Salmonella will be the topic.