Norovirus is spreading “more frequently” than expected in Canada, specifically in Ontario and Alberta, according to the Public Health Agency of Canada (PHAC).
Norovirus is a common and highly contagious virus that causes nausea, vomiting, abdominal pain, cramps and diarrhea.
“The number of reported norovirus cases has been higher than expected in 2024 compared to the historical average for the previous five years,” a PHAC spokesperson told CTV News Toronto.
Specifically, PHAC noted an increase in Ontario, Alberta and, to a lesser extent, British Columbia, Saskatchewan, Manitoba, New Brunswick and Newfoundland and Labrador.
The health agency acknowledged that the five-year historical average on which the current increase is based includes several years of the COVID-19 pandemic, a time of declining norovirus reports.
Dr. Susy Hota, chair of Infectious Diseases Leadership at the University Health Network, said the pandemic is also one of the reasons we are seeing more cases.
“People are doing more social things and going on cruises and those types of exposures that pose a risk of contracting norovirus,” Hota said.
“I think we’ll still see some changes in the behavior of common viruses because of the three years in which people did less and interacted less.”
Toronto Public Health (TPH) and Public Health Ontario (PHO) do not track norovirus cases. However, TPH does look at outbreaks, localized increases in the rate of infection or illness, above what is expected, in hospitals, nursing homes and nursing homes.
As of Thursday’s most recent report, three outbreaks have been reported at Toronto healthcare institutions.
While we are seeing “a little more” of norovirus this year compared to previous years, Hota said, “[it’s] “Nothing terribly unusual, just more than we expected.”
What is norovirus?
Norovirus, also known as “Norwalk virus,” named for the first outbreak in Norwalk, Ohio, involves diarrhea, vomiting, nausea, stomach pain and cramps. Fever, chills, headache, body and muscle aches, and fatigue are some of the other symptoms.
It is the most common form of stomach flu, represent more than 60 percent of casesaccording to the National Collaborating Center for Infectious Diseases.
How does norovirus spread?
Norovirus is transmitted through contaminated surfaces and close contact with infected people, but it also has a “resistance,” as Hota characterizes it, that makes the virus highly contagious.
It is difficult to remove the virus from surfaces because alcohol-based hand gel is not as effective at killing norovirus as it can withstand relatively high levels of chlorine, making hand washing the best defense.
After contracting the disease, it can take 12 to 48 hours to develop symptoms, which usually worsen in the first 48 to 72 hours, according to Hota.
“The thing is, you’re still contagious to others until about 48 hours after the stool has formed again and the diarrhea stops,” he said.
What do you do if you contract norovirus?
There is no treatment for norovirus that is specific for the infection. “Your body will take care of it,” Hota said. According to PHAC, a healthcare provider can diagnose the virus by taking a stool or vomit sample for laboratory testing.
“It’s miserable to get through those first 48 hours, but the important thing is to stay hydrated,” Hota added.
Anti-nausea medications can be taken to relieve some of the symptoms, but ultimately, he said, simply letting the infection “go away” is the best course of action.