Norovirus

CDC. US: Norovirus is a very contagious virus. You can get norovirus from an infected person, contaminated food or water, or by touching contaminated surfaces. The virus causes your stomach or intestines or both to get inflamed (acute gastroenteritis). This leads you to have stomach pain, nausea, and diarrhea and to throw up.
Anyone can be infected with norovirus and get sick. Also, you can have norovirus illness many times in your life. Norovirus illness can be serious, especially for young children and older adults.

Norovirus is the most common cause of acute gastroenteritis in the United States. Each year, it causes 19-21 million illnesses and contributes to 56,000-71,000 hospitalizations and 570-800 deaths. Norovirus is also the most common cause of foodborne-disease outbreaks in the United States.
The best way to help prevent norovirus is to practice proper hand washing and general cleanliness.


Symptoms

Norovirus causes inflammation of the stomach or intestines or both. This is called acute gastroenteritis.
The most common symptoms—

• diarrhea
• throwing up
• nausea
• stomach pain

Other symptoms—

• fever
• headache
• body aches

If you have norovirus illness, you can feel extremely ill and throw up or have diarrhea many times a day. This can lead to dehydration, especially in young children, older adults, and people with other illnesses.
Most people with norovirus illness get better within 1 to 3 days.
Symptoms of dehydration—

• decrease in urination
• dry mouth and throat
• feeling dizzy when standing up

Children who are dehydrated may cry with few or no tears and be unusually sleepy or fussy.


Transmission

Norovirus is a highly contagious virus. Anyone can get infected with norovirus and get sick. Also, you can get norovirus illness many times in your life. One reason for this is that there are many different types of noroviruses. Being infected with one type of norovirus may not protect you against other types.
Norovirus can be found in your stool (feces) even before you start feeling sick. The virus can stay in your stool for 2 weeks or more after you feel better.
You are most contagious

• when you are sick with norovirus illness, and
• during the first few days after you recover from norovirus illness.

You can become infected with norovirus by accidentally getting stool or vomit from infected people in your mouth. This usually happens by

• eating food or drinking liquids that are contaminated with norovirus,
• touching surfaces or objects contaminated with norovirus then putting your fingers in your mouth, or
• having contact with someone who is infected with norovirus (for example, caring for or sharing food or eating utensils with someone with norovirus illness).

Norovirus can spread quickly in closed places like daycare centers, nursing homes, schools, and cruise ships. Most norovirus outbreaks happen from November to April in the United States.


Treatment

There is no specific medicine to treat people with norovirus illness. Norovirus infection cannot be treated with antibiotics because it is a viral (not a bacterial) infection.
If you have norovirus illness, you should drink plenty of liquids to replace fluid lost from throwing up and diarrhea. This will help prevent dehydration.
Sports drinks and other drinks without caffeine or alcohol can help with mild dehydration. But, these drinks may not replace important nutrients and minerals. Oral rehydration fluids that you can get over the counter are most helpful for mild dehydration.
Dehydration can lead to serious problems. Severe dehydration may require hospitalization for treatment with fluids given through your vein (intravenous or IV fluids). If you think you or someone you are caring for is severely dehydrated, call the doctor.

Norovirus and food

Norovirus is the leading cause of illness and outbreaks from contaminated food in the United States. Most of these outbreaks occur in the food service settings like restaurants. Infected food workers are frequently the source of the outbreaks, often by touching ready-to-eat foods, such as raw fruits and vegetables, with their bare hands before serving them. However, any food served raw or handled after being cooked can get contaminated with norovirus.
Norovirus outbreaks can also occur from foods, such as oysters, fruits, and vegetables, that are contaminated at their source.