Noroviruses are human RNA viruses in the family Caliciviridae and are a major cause of epidemic gastroenteritis( inflammation of the gastrointestinal tract). They are responsible for at least 95% of viral outbreaks. They are highly contagious and are sometimes called food poisoning because they can be transmitted through food and water that has been contaminated with the virus. Infection with noroviruses are generally acute and self limited. They survive and live in places like restaurant, day care centres and nursing homes. Since they are highly contagious, they can survive temperature extremes in water and and in surfaces, this is one of their virulence factor.
The people that are usually affected are young children and the elderly ones. This is because in the elderly ones, they have reduced immune system and thus will not have effective defense system that will ward off the virus while in young children (infants) there is also underdeveloped immune system. This meaning that their immune system have not been fully developed and thus are also susceptible to the viral infection.
Transmission
As said earlier Fecal-oral spread is generally the most important mode of transmission of Noroviruses. They can also enter the food chain through contamination by food handlers who have been infected with the virus.
It necessary to point out here that these virus are very and extremely stable and they can remain infectious for weeks or months in the environment.
These calls for proper hygiene practice among the human population.
Symptoms
Nausea, vomiting (more often in children), watery diarrhea (more often in adults) and stomach cramps, chills, muscle aches, fatigue, low grade fever and headache are the common symptoms experienced. Most of the symptoms are not serious but diarrhea and vomiting can deplete the body fluids and thus lead to dehydration, this is often associated with adults but not specifically as it can also occur in children
Diagnosis
One of the effective way of diagnosing this virus is through the examination of diarrhoric stool sample from the infected patient. This is done to done to detect the presence of the virus in the stool. A more sensitive method is the use of Real time Polymerase chain reaction (RT-PCR )
Treatment
Norovirus like other viruses do not respond to antibiotics which are designed to kill bacteria.
No antiviral drug can treat noroviruses
but in healthy people, the ilnes is generally acute and self limited within 3days of infection, but can last up-to one week. Oral rehydration solution (such as pedialyte) is given to children to replace lost fluids and electrolytes. Avoidance of sugar drinks, as well as alcohol and Cafffeinated beverages which can dehydrate the person further is very important.
Prevention
Good hygiene is the key to prevention especially when one is close to other people.
Washing of raw fruits and vegetables thoroughly also reduces the chances of one been infected. Oysters and other Shel fish must be thoroughly and well cooked before eating them.
Conclusion
It is important that we maintain the culture of personal hygiene bearing in mind that these viruses have no cure, though they are self limited but can be fatal. Wash fruits and Cook foods well before eating them.
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References :
https://mdpi.com/journal/viruses
Viruses 2010, 2, 748-781; doi:10.3390/v2030748
https://thejournalofpathology.com
J Pathol 2015; 235: 206–216
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