Norovirus: Everything You Need to Know
Are you experiencing symptoms of the stomach flu or a stomach bug?
It is likely norovirus, a common virus not connected to the flu.
Norovirus is a stomach and intestinal virus that is very common and contagious. The most common symptoms of norovirus infection are nausea, vomiting, and diarrhea. It can spread from person to person or through contaminated food or surfaces. The symptoms usually start within 12 to 48 hours after exposure and run up to three days. There is no specific medicine or vaccine for norovirus except to rest and rehydrate. The most significant complication is dehydration, especially in the young, the older, and those with underlying health conditions. Proper hand washing and disinfection of contaminated surfaces may help prevent infections.
This article will define the symptoms, causes and diagnosis of norovirus infection. We will also explain the effective treatment and prevention strategies for better outcomes and promote optimal recovery.
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Overview
What is Norovirus?
Have you ever heard of Norovirus?
It is a Stomach bug!
Norovirus, also called Norwalk virus or the winter vomiting disease, is the leading cause of gastroenteritis (Stomach flu). The virus is highly contagious and usually transmitted by fecal-oral route. It can spread directly from person to person or indirectly through contaminated food, water, air, or surfaces. Norovirus outbreaks occur more frequently in winter. It is the leading cause of foodborne outbreaks in the United States.
The norovirus got its name from Norwalk, Ohio, US, following the first outbreak at a school in 1968.
Norovirus and the Stomach flu:
Norovirus causes gastroenteritis, sometimes called “stomach flu” or “stomach bug”. However, it does not have a connection with the flu, a respiratory infection caused by the influenza virus.
Types of Norovirus
Noroviruses (NoV) are a genetically diverse group of single-stranded RNA viruses. It belongs to the Caliciviridae family of viruses. A person can get norovirus illness multiple times throughout life because of several norovirus strains. An infection with one strain of norovirus may not protect against other strains.
A person can develop immunity against specific types, but the duration of this immunity is uncertain. It may explain high infection rates during norovirus outbreaks.
Signs and Symptoms of Norovirus
Norovirus causes inflammation of the stomach and intestines, called acute gastroenteritis. The usual onset of infection is between 12 and 48 hours after exposure to the virus, and symptoms last for 1 to 3 days. They can range from mild to severe.
The most common symptoms of norovirus are:
- Diarrhea
- Nausea
- Vomiting
- Stomach pain
It can also cause:
- Headache
- Fever
- Body aches
- Chills
Dehydration
Individuals infected with norovirus can feel extremely sick and have frequent episodes of vomiting and diarrhea. This results in dehydration (loss of body fluids), particularly in young children, older people, and those with other illnesses.
Symptoms of dehydration are:
- Dry mouth and throat
- Dizziness
- Decrease in urination
When a child cries with few or no tears, it is a common sign of dehydration. They may also act sleepy or fussy. Seek medical care immediately.
Is Norovirus Contagious?
Yes! Norovirus is highly contagious. It can spread from person to person by the fecal-oral route.
When a person has norovirus, his body sheds billions of tiny virus particles that can make others sick, too. NoV shedding in the infected person’s stools and vomit is maximum within the first 24 to 48 hours after symptoms appear, with an average duration of four weeks.
Viral shedding in the stools of immunocompromised persons can last up to several months after infection.
Noroviruses can survive on surfaces and objects for days or even weeks. Noroviruses are challenging to eliminate because of their ability to survive in hot and cold temperatures. They are also resistant to most disinfectants.
Who is at Higher Risk?
Norovirus infection can affect people of all ages, but certain groups are at higher risk, including:
- Young children (under the age of 5) and older adults
- People with weakened immune systems (such as cancer or HIV/AIDS patients)
- People with chronic health conditions (such as kidney disease, diabetes, or liver disease)
- Pregnant women
- Those who live in closed or semi-closed communities (like nursing homes, hospitals or retirement centers)
- Genetic susceptibility
Causes of Norovirus (How it Spreads)
Norovirus is very contagious. It spreads through contaminated food objects, surfaces, or in the feces and vomit of infected individuals. The most common ways to contract the virus are:
Contact with Infected Individuals
Norovirus can spread through direct (physical) contact with infected persons, like sharing, caring, or eating with them.
Contact with the Contaminated Surface or Object
A person can get NoV infection by touching a contaminated surface or object and putting unwashed fingers in his mouth or nose.
Contaminated Food
Eating and drinking foods or liquids contaminated with norovirus can also spread infection. Norovirus is the leading cause of foodborne diseases. It is usually present in seafood (including oysters or raw shellfish), leafy green vegetables (such as kale, spinach, and lettuce), and fresh fruits. It generally spreads through food points like restaurants.
A person can transmit the virus from the onset of symptoms until several days after recovery, even after feeling better. Noroviruses can survive on surfaces and objects for up to many weeks and are resistant to extreme temperatures and many disinfectants.
Diagnosis of Norovirus
Diagnosis of norovirus infection depends on the patient’s symptoms. When a person has a weakened immune system (ability to fight infection) or has other medical conditions, the healthcare provider can also test a stool sample to confirm the diagnosis.
The most common diagnostic test is real-time polymerase chain reaction (RT-PCR) assay, which rapidly detects the virus in the stool sample. This assay is very sensitive and reliable.
Commercially available tests such as ELISA (enzyme-linked immunosorbent assay) use antibodies against a mixture of norovirus strains but have less specificity and sensitivity.
Norovirus diagnostic tests are not widely available in developing countries. However, healthcare facilities use laboratory testing to investigate norovirus outbreaks.
Treatment of Norovirus
There is currently no specific medicine for norovirus infection. Treatment for the disease focuses on alleviating the symptoms. And recovery depends on the power of the immune system. Most people with norovirus illness get better within a few days.
Norovirus infection does not respond to antibiotics because they target bacteria, not viruses.
Some self-care tips are:
- Stay home and take a rest
- Drink plenty of fluids to replace electrolytes
- Eating soft foods (like soups, rice, pasta, yogurt or eggs)
- Infants will continue breastfeeding or formula-feeding
In norovirus illness, it is necessary to watch for signs of dehydration (loss of body fluids). Drink plenty of liquids to replace fluid lost from vomiting and diarrhea to prevent dehydration. Oral rehydration solutions (ORS) are helpful for mild dehydration.
When people cannot drink enough fluids, dehydration can cause serious health complications. Immediate hospitalization is necessary to receive intravenous or IV fluids. Healthcare providers can also recommend over-the-counter (OTC) anti-diarrheal and antiemetic medications.
Prevention of Norovirus
Norovirus is highly contagious and persistent. Currently, there is no vaccine available to prevent norovirus infection. However, this is an area of active research.
A person can protect himself and others from norovirus transmission by following simple prevention tips, including:
Proper Hand Hygiene
Washing hands properly with soap and water for at least 20 seconds is an effective way of reducing the transmission of norovirus. It is necessary, especially after using the toilet or changing diapers, always before eating or preparing food and taking or giving medicines to someone else.
Hand sanitizers (alcohol based ≥62% isopropyl alcohol) are not as effective against norovirus as washing hands with soap and water.
Handle and Cook Food Carefully
Wash all the fruits and vegetables carefully before eating and preparing them. Cook food (especially shellfish and other seafood) thoroughly at high temperatures (at least 145° F). Remember that noroviruses resist heat and can survive high temperatures and quick steaming processes.
Protect Others
Symptoms of norovirus? Do not prepare food or look after others. Protect others by staying home when sick for at least 2 to 3 days after symptoms stop.
Children should also stay home from daycares or schools. The same rule applies to sick workers in schools, daycares, restaurants, and other places where they may spread norovirus infection.
Disinfect Surfaces
Always clean and disinfect the contaminated or high-touch surfaces thoroughly. Wear disposable gloves and disinfect the surfaces with a disinfectant approved as effective against norovirus by the Environmental Protection Agency (EPA).
A chlorine bleach solution with a concentration of 1000 to 5000 ppm (parts per million) is also effective.
Wash Laundry Carefully
Remove and wash clothes and linens immediately contaminated with vomit or poop. Wash the laundry carefully with detergent and hot water. Wear disposable gloves while cleaning and handling soiled materials, and wash your hands afterward. Dispose of soiled materials properly in plastic bags without agitating them.
Norovirus Reocurring
Remember! Norovirus is highly contagious. A person can transmit norovirus for up to 2 weeks after symptoms disappear. There are several norovirus strains, and the human body can develop some immunity (protection against the virus) to the first norovirus strain, but not all strains. It means a person can get norovirus infection multiple times throughout their life.
Norovirus Prognosis
Norovirus is a highly contagious gastrointestinal virus. It is transmitted through contaminated surfaces, food, water, and air, or contact with infected persons.
The onset of norovirus symptoms is usually sudden and can be severe, including nausea, vomiting, stomach cramps, and diarrhea. Symptoms typically last for a few days until the infection runs its course.
There is no specific treatment for norovirus. It is better to stay home and stay hydrated until symptoms disappear, as the infected person can transmit the virus to others.
Most people fully recover from norovirus; however, symptoms can have a significant impact on the health of infants. It may also take longer to recover from the virus in older patients with weaker immune systems or other chronic health problems.
Severe vomiting and diarrhea can result in dehydration. In severe cases, hospitalization may be necessary, and it may take weeks for the body to recover fully.
There are several norovirus strains, and anyone can get a norovirus infection more than once, as the body does not build immunity to every strain. However, the illness is temporary and does not lead to any long-lasting effects.
Take Action
Norovirus can be unpleasant, but it is not typically a cause for concern. It is very contagious, so it is important to protect yourself and your community by following safety measures like washing hands and avoiding contact with infected individuals. If your symptoms do not improve after three days, do not hesitate to seek guidance from a healthcare professional.
FAQs
What are the initial symptoms of norovirus?
The onset of symptoms can occur within 12 hours or a few days after exposure. The initial symptom may be nausea, followed by vomiting and diarrhea.
When should I seek medical advice?
Seek medical advice if a person cannot eat or drink. Moreover, if symptoms persist for over three days, a person should contact a healthcare provider, as this may cause dehydration.
What is the duration of norovirus in the human body?
When norovirus enters your body, it is present in your stool before you experience signs and symptoms. It can stay in the human body for up to two weeks after symptoms stop. You are contagious after you get infected with norovirus until 48 hours after symptoms disappear.
What is the difference between norovirus and rotavirus?
Norovirus and rotavirus cause inflammation of the stomach and intestines (gastroenteritis). However, there are significant distinctions:
I hope what I’ve written here will help people to manage and prevent norovirus infection a little better.
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