Canadian health officials are reporting a growing number of cases of the highly contagious norovirus disease in Canada, warning that the elderly and young children are most at risk.
Dr. Zain Chagla, an infectious disease specialist at St. Joseph’s Healthcare in Hamilton, Ontario, says he’s currently seeing more cases of “winter vomiting disease.”
“These are probably post-pandemic patterns that are just normalizing and (we’re) seeing in Canada and even the United States,” Chagla said in an interview with CTV Your Morning on Monday. “But this is the time we look forward to it.”
Norovirus, also known as the flu or stomach bug, is a common gastrointestinal illness that occurs most often during the winter and early spring, when people spend more time together indoors, according to the Center for Disease Control. British Columbia (BCCDC).
Norovirus symptoms
Symptoms include vomiting, diarrhea, stomach pains and nausea, according to the Public Health Agency of Canada (PHAC).
The disease typically spreads when people come into close contact with affected people or contaminated surfaces, he said.
People typically have symptoms that last 24 to 72 hours, according to the BCCDC.
Cases in Canada
Preliminary data indicates that a higher number of norovirus cases are being reported in recent weeks compared to the historical five-year average from 2019 to 2023, including in Alberta, Ontario, British Columbia, Nova Scotia, Saskatchewan and the Island of the Prince Edward, according to PHAC. in an email to CTVNews.ca on Thursday.
However, he cautioned that the comparison should take into account factors related to the COVID-19 pandemic, which resulted in a “significant reduction in reports” of enteric pathogens such as norovirus and reduced the five-year average during that period.
“As a result, recent trends may appear higher than expected compared to the 2019-2023 reference period, but align with trends observed in the pre-pandemic five-year reference period (2015-2019)” , wrote.
PHAC said it cannot release any preliminary data until it is validated by provincial and territorial authorities.
Similarly, Alberta Health says cases have increased over the years, with 295 incidents in 2022, 513 in 2023 and 654 last year. However, he said no outbreaks were reported to the chief medical officer of health during that period, although they are common and can occur at any time during the year.
“Although Alberta has seen an increase in cases over the past few weeks, which is not unusual to see…in the winter months, there are no confirmed norovirus outbreaks in Alberta at this time,” according to the Health Minister’s office of Alberta in an email to CTVNews.ca on Friday.
The BCCDC reports an “increasing amount of norovirus activity” in British Columbia, which it rates as “typical” for this time of year.
“The levels of illness we’ve seen to date are elevated compared to previous years,” he said. However, he said the data was not immediately available.
Gastrointestinal outbreaks, including those caused by norovirus, have increased over the past two years, according to Prince Edward Island’s Chief Public Health Office in an email sent to CTVNews.ca on Monday.
In 2023 there were 15 gastrointestinal outbreaks and in 2024 there were 26 outbreaks in the province.
Meanwhile, two long-term care homes in Saskatchewan are experiencing a norovirus outbreak, according to the Saskatchewan Health Authority in an email sent to CTVNews.ca on Friday. “While we don’t immediately have specific data, this is typical for this time of year.”
Treatment for norovirus
Experts say there is no treatment for norovirus, but those experiencing severe fluid loss are advised to seek medical attention.
People should drink small amounts of fluids, such as electrolyte-based solutions like Gatorade and Pedialyte, during the vomiting phase, which lasts about 24 hours, Chagla says.
“As long as people are generally healthy, as long as they get through that vomiting phase and the vomiting calms down, they can start to hydrate again, most people will be able to tolerate the illness,” he said.
Norovirus prevention
Health experts say norovirus can spread through direct contact with contaminated food, water and surfaces.
They said hand sanitizer is not effective in preventing the virus, unlike soap and water. For disinfecting surfaces, bleach-based cleaning products are better, although they can be more toxic than regular products, so consumers should follow directions, Chagla added.
To avoid getting sick and spreading norovirus, practice good hygiene habits, such as washing your hands thoroughly with soap and water for at least 20 seconds after using the bathroom, after changing diapers, and before eating, preparing or handling food, according to the US. .US Centers for Disease Control and Prevention (CDC).
Additionally, wash fruits and vegetables and cook seafood thoroughly, he added, as well as clean and disinfect contaminated surfaces and wash clothing in hot water. If you are sick, stay home for 48 hours after your symptoms disappear, he added.
Most people improve in one to three days, the CDC said.
Who is most vulnerable?
The disease can cause dehydration and even death, with older adults and young children most at risk, according to health officials.
When is norovirus most contagious?
According to Chagla, norovirus is most contagious when people start having diarrhea and vomiting.
“The problem with norovirus is that it takes as few as 15 viral particles (that’s a micro, microscopic amount of virus) for someone to become infected,” he told CTV Your Morning. “The worst thing is obviously when you have diarrhea and vomiting, which is full of millions and millions of viruses.”
People who have norovirus should “aggressively wash their hands” with soap and water and avoid high-risk environments where they could spread it even after recovering, since they could still be shedding viral particles, Chagla suggested.
With files from Jermaine Wilson of CTVNews.ca
