Norovirus: What to know about the ‘extremely common’ bug as cases rise in Canada

Click to play video: 'What you need to know about the norovirus, gastrointestinal illnesses linked to raw oysters'
What you need to know about the norovirus, gastrointestinal illnesses linked to raw oysters
WATCH: What you need to know about the norovirus, gastrointestinal illnesses linked to raw oysters – Apr 19, 2018

The very contagious norovirus that is known for causing inflammation of the stomach and intestines is rising across the country — but it is not uncommon during this time of the year, according to the Public Health Agency of Canada (PHAC).

The number of cases of norovirus has been on the rise “both at the national level and within several provinces,” since January, PHAC confirmed to Global News in an email Wednesday. Infections have increased in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, and New Brunswick as well as Newfoundland and Labrador, the agency said.

The agency noted that the number of cases reported to the National Enteric Surveillance Program (NESP) since Jan. 1 “is generally comparable with the number of cases reported in the same seasonal period of previous years (i.e., 2015 – 2019).” The agency uses different surveillance systems to monitor outbreaks of norovirus, including the NESP which oversees data for 14 different pathogens that cause foodborne illness.

Story continues below advertisement

While there is no prescription medication to treat norovirus, according to Health Canada’s website, “most people begin to feel better on their own” within two to three days of infection.

There are no “long-term health effects. People can also get norovirus more than once,” the website states.

Click to play video: '123 people ill after suspected norovirus outbreak at Calgary shawarma restaurant: AHS'
123 people ill after suspected norovirus outbreak at Calgary shawarma restaurant: AHS

According to Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital, many people experience “pretty significant nausea and vomiting” post-infection, “but then people tend to recover over the next couple of days.”

Some symptoms of norovirus include diarrhea, stomach pain, and cramps. Some may also experience chills, fatigue, headache, muscle aches and even low-grade fever, Health Canada states on its website.

Story continues below advertisement

“It’s important to remember that norovirus, sadly, is extremely common,” Bogoch told Global News. “The real treatment for this is rest and keeping up with fluids and electrolytes.”

How does norovirus spread?

Norovirus spreads through sharing food or utensils with an infected person, according to Health Canada’s website. It can also spread if one touches their mouth without washing hands after touching a contaminated surface.

The latest health and medical news emailed to you every Sunday.
Receive the latest medical news and health information delivered to you every Sunday.

Get weekly health news

Receive the latest medical news and health information delivered to you every Sunday.
By providing your email address, you have read and agree to Global News' Terms and Conditions and Privacy Policy.

Eating contaminated food or drinking contaminated liquids is also responsible for the spread norovirus between people, the website states.

According to PHAC, about four million people in Canada get sick every year from the food they consume. “Norovirus causes more than 1 million cases of non-travel related foodborne illness each year,” the agency said.

However, most people make “a full recovery,” from norovirus, said Bogoch.

Story continues below advertisement

“We just have to watch for more vulnerable individuals, especially the youngest and the oldest who might not be able to keep up with their fluids and electrolytes,” the doctor said.

Cases of norovirus have been on the rise in the United States as well. According the to the U.S. Centre for Centers for Disease Control and Prevention (CDC), from August 2022 to early January, 225 norovirus outbreaks were reported by states taking part in a federal surveillance program.

Norovirus can easily contaminate food and water because it only takes a very small amount of virus particles to make a person sick, the U.S. CDC says on their website.

“Food and water can get contaminated with norovirus in many ways,” the agency states. Moreover, food that “is grown or harvested with contaminated water, such as oysters harvested from contaminated water, or fruit and vegetables irrigated with contaminated water in the field,” can lead to the spread of norovirus.

How to prevent the virus from spreading

Bogoch said PHAC’s “surveillance for this is as good as it can be,” so the key things for Canadians to follow in order to curb spread are hand sanitization and staying home when they feel sick.

Story continues below advertisement

“Soap and water (are) the most appropriate way to wash your hands. Norovirus is pretty hardy. It can stick to surfaces and survive on surfaces rather easily,” cautioned Bogoch.

The norovirus is quite resistant to heat and cold, said Bogoch and it can also withstand alcohol. So, “the alcohol hand sanitizers don’t do as good a job as soap and water.”

Noroviruses can infect people of all ages, according to Bogoch and most outbreaks occur in clusters and in places where people come in close contact like schools, cruise ships or hospitals.

Click to play video: 'Concerned parents impressed school’s handling of potential norovius outbreak'
Concerned parents impressed school’s handling of potential norovius outbreak

But there are ways to protect oneself and other people.

Story continues below advertisement

Health Canada says additional precautions like cooking shellfish thoroughly before eating, especially oysters and clams, as well as raw fruits and vegetables, help curb the virus from spreading. Other recommendations from the agency include cleaning and disinfecting surfaces “after an episode of illness” and immediately washing clothing and linens “that are soiled with vomit or diarrhea.”

Why is the norovirus spreading now?

According to PHAC, during the height of the COVID-19 pandemic period in 2020, people were wearing masks, hand sanitizing more frequently and practicing physical distancing with others, which “significantly reduced” the spread of pathogens like the norovirus.

“Comparison of norovirus cases reported to date in 2023 against those reported during the height of the COVID-19 pandemic period (i.e., 2020 – 2022) should be carried out with caution,” said PHAC, “as several factors associated with the pandemic resulted in significantly reduced reporting of enteric pathogens, including norovirus.”

Story continues below advertisement

Bogoch also pointed out that a lot of times cases of norovirus go unreported as many don’t seek care for it.

“A lot of the time people that get this don’t need to seek care. They have a terrible bout of vomiting or sometimes diarrhea, and it gets better in a day or two,” said Bogoch.

Sponsored content