Amirabad Pathobiology and Virology Laboratory


Norovirus (Norwalk Virus)

Date: 2 سال قبل

author: AmirAbad

Norovirus (Norwalk Virus)
Noroviruses (NoV) are a genetically diverse group of single-stranded positive-sense RNA, non-enveloped viruses belonging to the family Caliciviridae. According to the International Committee on Taxonomy of Viruses, the genus Norovirus has one species, which is called Norwalk virus.
Norovirus is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Symptoms usually develop 12 to 48 hours after being exposed, and recovery typically occurs within 1 to 3 days. Complications are uncommon, but may include dehydration, especially in the young, the old, and those with other health problems.
The virus is usually spread by the fecal–oral route. This may be through contaminated food or water or person-to-person contact. It may also spread via contaminated surfaces or through air from the vomit of an infected person. Diagnosis is generally based on symptoms. 
Prevention involves proper hand washing and disinfection of contaminated surfaces. Alcohol-based hand sanitizers are not effective against the Norovirus, this is due to Norovirus being a non-enveloped virus. There is no vaccine or specific treatment for norovirus. Management involves supportive care such as drinking sufficient fluids or intravenous fluids. 
Signs and symptoms
Norovirus infection is characterized by nausea, vomiting, watery diarrhea, abdominal pain, and in some cases, loss of taste. A person usually develops symptoms of gastroenteritis 12 to 48 hours after being exposed to norovirus. General lethargy, weakness, muscle aches, headaches, and low-grade fevers may occur. The disease is usually self-limiting, and severe illness is rare. Although having norovirus can be unpleasant, it is not usually dangerous, and most who contract it make a full recovery within two to three days.
Norovirus can establish a long term infection in people who are immunocompromised, such as those with common variable immunodeficiency or with a suppressed immune system after organ transplantation. These infections can be with or without symptoms. In severe cases, persistent infections can lead to norovirus‐associated enteropathy, intestinal villous atrophy, and malabsorption.
Specific diagnosis of norovirus is routinely made by polymerase chain reaction (PCR) assays or quantitative PCR assays, which give results within a few hours. These assays are very sensitive. Tests such as ELISA that use antibodies against a mixture of norovirus strains are available commercially.
There is no specific medicine to treat people with norovirus illness. Norovirus infection cannot be treated with antibiotics because it is a virus. Treatments aim to avoid complications by measures such as the management of dehydration caused by fluid loss in vomiting and diarrhea, and to mitigate symptoms using antiemetics and antidiarrheals.

Write Comment


Register now and get the test results online


labratory locations