Noroviruses are highly contagious viral infections that cause inflammation of the stomach and the lining of the large intestines leading to vomiting, diarrhea and occasional stomach cramps. In addition to these, the individual may feel tired, have headaches and muscle aches and experience a low-grade fever (101F). It is the leading cause of gastroenteritis in close and crowded settings like hospitals, nursing homes and cruise ships. Symptoms usually start 12-48 hours after exposure to the virus and may last a few days. Generally, noroviruses clear on their own without treatment but in infants, the elderly and people with compromised immune system, diarrhea and vomiting may lead to dehydration which may require medical attention. Noroviruses used to be called food poisoning because they can be transmitted through food or water contaminated with fecal matter during preparation. They can also be transmitted through close contact of an infected person – especially in hospitals, schools, prisons and nursing homes and by coming in contact with a contaminated surface. It is sometimes called “the winter vomiting virus” or the stomach flu although it has no connection to the influenza virus.
Noroviruses are highly contagious and once a person contract it they attach to the cells of the GI tract and trigger vomiting. They also prevent good fluid absorption which then results in diarrhea. This fecal matter contains the highly contagious virus. People hence become infected when they come into contact with the fecal matter or eat food or drink fluids contaminated with the virus. You can also get the virus if you touch a contaminated surface or object and use it to touch your nose, mouth or eyes. In some cases, raw fruits, oysters and salads have been responsible for the outbreak. This occurs when infected food handlers transfer the virus to the food before it is served. The norovirus is difficult to eradicate because they can withstand extreme temperatures and most disinfectants.
Certain factors put you at high risk of being infected with the norovirus. These include :
Having a compromised immune system
People with children in schools and daycare
Living in crowded areas like prisons, nursing homes and hospitals
Living in a place with improper sanitary food preparation
Travelling on cruise ships and staying in hotels and vacation resorts.
A person who contracts the virus may quickly switch from being completely healthy to becoming very sick within 12 to 48 hours (incubation period) of getting the virus. Signs and symptoms of norovirus infection include the following:
Loss of taste
Infants, immunocompromised patients and the elderly may lose a lot of body fluid from the vomiting and diarrhea which can lead to electrolyte imbalance, coma or even death. Call your doctor immediately if you see any signs of dehydration in this category of people. Also if symptoms don’t go away after 3 days, you have to seek medical attention. Note that infected people continue to shed the virus up to 3 days after recovery and some people do not show any signs and symptoms but are still contagious and can shed the virus.
TESTS AND DIAGNOSIS
Your doctor will usually ask you about your symptoms and use that for his diagnosis. He will further get a sample of your stool for testing in the lab and use it to confirm his diagnosis.
Noroviruses usually resolve on their own without any medical treatment. In cases where the infected person becomes dehydrated the main goal is to replace fluid lost. If the person is unable to drink adequate water to replace the fluid, it may be given intravenously. Oral hydration solutions like Pedialyte, Enfalyte or pediatric electrolyte can be given to children who are dehydrated to replace fluid and electrolyte. For adults sports drinks, sprite or juices without any pulp are recommended. Avoid drinks that contain sugar – they only make diarrhea worse. Severe nausea can be treated with medicines like prochlorperazine (Compazine), promethazine (Phenergan) or ondansetron (Zofran) to prevent vomiting. Pregnant women should rehydrated quickly when they get infected with the norovirus because they are more prone to dehydration than non pregnant females or healthy males.
Most cases of noroviruses resolve on their own but in children, the elderly and immunocompromised patients dehydration can be a fatal complication leading to a coma or even death.
Certain measures can be taken to prevent a norovirus infection. These include:
Stay home from work if you have the virus.
Wash hands thoroughly after using the toilet or changing a diaper.
Avoid foods and drinks contaminated with the virus – eg shellfish coming from contaminated water.
Disinfect contaminated surfaces with chlorine bleach solutions.