Norovirus is likely the cause of the gastroenteritis outbreak at the University of Guelph, according to Wellington-Dufferin-Guelph Public Health.
As of Friday afternoon there were 190 self-reported cases at the university, primarily among students in residence buildings. Most cases have been in South Residence, though there have been others reported throughout and beyond campus.
Norovirus is the leading cause of gastroenteritis, or stomach flu. Often called the winter vomiting disease, symptoms include diarrhea, vomiting, nausea, stomach pain or cramping. More vulnerable populations can also experience fever or chills, headache, body aches and fatigue.
WDG Public Health reported one positive sample of norovirus among the cases Friday morning.
"That gives us confidence to say that the likely issue is norovirus," said spokesperson Danny Williamson. He added there could be other issues going on as well, given that it's a big campus.
"But we're pretty confident that noro is the overall underlying issue."
Norovirus cases are typically more common in the winter, said Lawrence Goodridge, a professor at the U of G and the Canada Research Chair in Foodborne Pathogen Dynamics.
"It's spread person to person, but generally through poor hygiene," like not washing hands, he said. It's not airborne, but can survive on surfaces.
"So if people vomit and the surface isn't cleaned properly, the virus can survive for long periods of time," he said. "Then somebody touches the surface and their mouth, and here we go again. It's the same virus you hear about in cruise ships, lots of people in close proximity."
Symptoms can come as quickly as 12 hours after exposure.
Most cases seem to be lasting 24 to 48 hours without people needing to take additional steps. Though, Williamson said if people are feeling really sick and can't manage their symptoms at home, they're encouraging people to contact a primary care provider.
Williamson said the cluster of cases is primarily connected to the university, but it's still something the broader community should be aware of.
Goodridge said it's possible but unlikely the outbreak will spread off campus.
Reports have suggested Canada and the U.S. are seeing more cases of norovirus than normal, higher than the five year average. But Goodridge cautions against using the last five years as a measurement.
"We have to be careful with interpreting five year averages, because the pandemic changed everything. The dynamics of how people interacted with others were different. we stayed away from large gatherings where norovirus would thrive," he said.
"So to me, it's not surprising that we're seeing higher cases now than we did in the last five years. if you go and look at the previous five year average, what we're seeing here is not outside of the norm."
He emphasized hand washing, especially before preparing food, is crucial for reducing the risk, as well as frequently cleaning high-touch surfaces.
As of Thursday afternoon, the university said residence communities would be "temporarily moving away from larger-scale social programs" to help contain the spread, and that Student Housing Services would continue to monitor the situation and make adjustments accordingly.
Custodial staff are also doing additional cleaning and wearing protective equipment in infected areas on campus.
Updates from the university will be posted here.
