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What you need to know about norovirus with cases of stomach illness

What you need to know about norovirus with cases of stomach illness


Health

A norovirus infection is characterized by sudden vomiting and diarrhea.

What you need to know about norovirus with cases of stomach illness

This electron microscope image provided by the Centers for Disease Control and Prevention shows a cluster of norovirus virions. (Charles D. Humphrey/CDC via AP, File)

Cases of the unfortunate stomach bugs have increased in parts of the United States this winter, according to government data.

The latest figures from the US Centers for Disease Control and Prevention show that 91 norovirus outbreaks were reported in the week of December 5, compared to 69 outbreaks in the last week of November.

Figures from recent years show a maximum of 65 outbreaks reported in the first week of December.

A norovirus infection is characterized by sudden vomiting and diarrhea. Outbreaks are often seen on cruise ships, in common living situations such as nursing homes and prisons, as well as in schools and places where people are in close proximity.

Here are some things to know about the virus.

What is norovirus?

Norovirus is the leading cause of foodborne illness in the United States, responsible for 58 percent of such infections acquired in the country each year, according to the CDC.

Norovirus infections are caused by a group of viruses that spread easily, with as few as 10 virus particles having the ability to make someone sick, health experts say.

There are approximately 2,500 norovirus outbreaks reported annually in the United States. Outbreaks can occur throughout the year, but are most common from November to April.

Along with vomiting and diarrhea, common symptoms include nausea, stomach pain, body aches, headache, and fever.

How do you get it?

Most norovirus outbreaks occur when people who are already infected spread the virus to others through direct means, such as sharing food or eating utensils. Outbreaks can also be widespread food, water or contaminated surfaces.

How long do you stay sick?

Illness caused by norovirus usually has a sudden onset, with symptoms developing 12 to 48 hours after exposure to the virus. Most people get better within one to three days and make a full recovery.

But with 19 to 21 million illnesses each year in the United States, norovirus still causes an average of 900 deaths and 109,000 hospitalizations annually, mostly among adults age 65 and older. It also leads to 465,000 emergency department visits, most involving young children.

Who is at risk?

People of all ages can become infected and sick with norovirus. Young children, the elderly and those with weakened immune systems are most at risk, with dehydration from vomiting and diarrhea being the biggest concern.

There are no drugs to treat norovirus. Rehydration is recommended through drinking water and other liquids, except coffee, tea and alcohol.

Anyone suffering from dehydration should seek medical help. Symptoms of dehydration include decreased urination, dry mouth and throat, and feeling dizzy when standing. Dehydrated babies may be unusually sleepy or restless and may cry with little or no tears.

How can I protect myself?

Thorough and frequent hand washing is the best defense against norovirus during the peak winter season, by scrubbing hands with soap and warm water for 20 seconds before meals.

Washing surfaces with household disinfectants can also help.