A new strain of norovirus, the most common cause of sudden intestinal illness, has shown up in Minnesota, and that could mean more norovirus illnesses this winter, state health officials warned today.
The new strain, called GII.17 Kawasaki, caused many outbreaks in Asia last winter before arriving in the U.S. MDH has investigated more than 20 outbreaks caused by norovirus since the beginning of September. The new strain first showed up in sporadic cases in the state earlier this year and the first outbreak caused by the new strain was reported last week. Reports of norovirus-like illnesses in the community have also increased in the past week.
“Every few years, a new strain of norovirus emerges and causes many illnesses. We don’t know yet if this new strain will lead to an increase in the number of outbreaks reported, but it could,” said Amy Saupe, a foodborne disease epidemiologist at the Minnesota Department of Health (MDH). “If we’re meticulous about washing our hands and handling food properly, we may be able to limit the impact.”
Illness caused by norovirus is often mistakenly called “stomach flu,” which is a confusing term because norovirus is not related to influenza. Influenza is a respiratory illness, with symptoms that include high fever, chills, body aches, sneezing, runny nose, sore throat, and/or coughing. Norovirus is not a respiratory illness, and is not spread through breathing or coughing.
“When people say that they have ‘stomach flu,’ referring to a short illness with diarrhea and/or vomiting, what they generally have is a norovirus infection,” said Saupe.
Norovirus can cause nausea, vomiting, diarrhea, abdominal pain, headache, body aches, a general run-down feeling, and a mild fever. Symptoms typically begin 24 to 48 hours after swallowing the virus, and usually last one to two days. The virus passes from one person to another by the fecal-oral route. That means the virus comes from the feces or vomit of people who are sick or were recently sick, and can make someone else sick if they get the virus in their mouth and swallow it. A tiny amount of virus can make someone sick.
“Fecal-oral transmission sounds gross, but it’s important for people to understand that they may have gotten their norovirus from food, and that they could pass the virus to others by handling food, even after their symptoms are gone,” Saupe said.
Norovirus is the most common cause of food-related illness in Minnesota. In a recent outbreak example, employees who had been sick with diarrhea prepared food items that were eaten by restaurant patrons and at least 25 patrons became ill from norovirus.
The majority of norovirus illnesses and outbreaks can be prevented through good handwashing and appropriate food handling. Always wash your hands well before preparing food, and do not prepare food for others (at home or for your job) at all if you have been sick with vomiting or diarrhea in the last three days. If you are sick with vomiting or diarrhea, wash your hands very carefully after using the restroom. Norovirus can be present in your stool for several days even after you are feeling better, so continue to be extra careful about handwashing.
Always wash your hands before eating. Do not eat food prepared by someone who is ill with vomiting or diarrhea. If someone in your household is sick with vomiting or diarrhea, have them use a separate bathroom, if possible. Clean surfaces with soap and water and sanitize with a bleach solution to kill any norovirus that was spread to bathroom or kitchen surfaces. Launder soiled clothing in hot water promptly. Wash your hands after helping children in the bathroom or touching surfaces that may have vomit or feces on them.
Thorough handwashing includes washing your hands with soap for at least 20 seconds, rinsing under running water, and drying with a towel.
“No one likes to get vomiting, diarrhea, and stomach aches, especially during the holidays,” Saupe said. “Norovirus tends to hit especially hard during the winter season, so now is a good time to get in the handwashing and norovirus prevention habit.”