Canadian health authorities worried about 2023 Norovirus outbreaks

News outlets are reporting a recent spike in norovirus cases, and the Public Health Agency of Canada (PHAC) has confirmed that, since January 2023, norovirus cases have risen sharply “both at the national level and within several provinces.”
Canadian health authorities worried about 2023 Norovirus outbreaks
February 16, 2023

According to PHAC’s data, there has been a large increase in reported norovirus infections in Alberta, British Columbia, Labrador, Manitoba, New Brunswick, Newfoundland, Ontario and Saskatchewan. 

Many cases tend to go unreported, so the actual number of cases may be larger than those reported by PHAC. This is because norovirus, also known as the stomach flu or viral gastroenteritis, is not usually life-threatening, nor does it often require hospitalization. Norovirus symptoms include nausea, vomiting and diarrhea, but patients usually recover in a couple of days without any special treatment - which is why a large number of cases go unreported.

This year’s number of outbreaks is larger than last year’s, and the authorities suspect it may be due to COVID protocols being relaxed. Since people were masking, socially distancing, and washing their hands more frequently last year, the virus spread slowed down compared to other years. But in 2023, norovirus cases are going back to pre-pandemic levels, or even higher.

What is norovirus?

Norovirus, the infamous “cruise ship bug”, is a virus (like SARS-CoV-2, which has been such a big part of our lives for the past few years). Norovirus belongs to the Caliciviridae family of viruses, and it consists of single strands of RNA genetic material. 

According to Health Canada, norovirus symptoms include diarrhea and vomiting, along with stomach pain and cramps. Some patients may also suffer from fever, chills, fatigue, body aches and headaches.

Norovirus is highly contagious: PHAC reports that every year, around 4 million people in Canada suffer from norovirus infections every year. They also report that norovirus causes more than 1 million cases of foodborne illness each year locally, not counting travel-related cases.

The virus itself is not dangerous to most people, but special care must be taken with children and patients of advanced age, who are more prone to dehydration and other complications.

How does norovirus spread?

Norovirus lives and spreads through people, unlike many illnesses which use animals as hosts or vectors. Lee-Ann Jaykus, professor of food bioprocessing and nutrition sciences at North Carolina State University, explains it like this: “The reservoir for norovirus is always humans or human waste material.” 

You may think that the risk of human waste material contaminating your food is really low, but it isn’t: a single gram of feces from an infected person contains billions of virus particles, and someone can become sick by ingesting as few as 10 of them. This means that the merest trace of a trace can put someone at risk of contracting norovirus.

On top of this, the virus has a very long lifespan, especially if it finds its way into water - as sewage often does. Water contaminated with even a small amount of waste with norovirus will stay contaminated (and potentially infectious) for a very long time.

Since the virus is so contagious, outbreaks are most common in settings where people are grouped closely together, such as cruise ships (hence the nickname.) That said, the majority of norovirus outbreaks occur in hospitals and long-term facilities, schools and childcare centres, and of course in restaurants and catered events. 

Besides being acquired through consuming contaminated food or water, norovirus also spreads really quickly from person to person through direct contact, contact with contaminated surfaces (such as handles and door knobs), and through sharing utensils and food. Health Canada also mentions that a common way for a person to contract norovirus is by them touching a contaminated surface and then their mouth, without washing their hands first.

How can I prevent norovirus from spreading? 

Food handlers and their managers have a great responsibility when it comes to preventing norovirus outbreaks, and extreme care must be taken to establish and follow food safety procedures and to ensure every single member of staff maintains strict personal hygiene. The Food Safety Plan must detail every step that staff members must take - and given the norovirus’s high infectiousness, the food safety manager must ensure everyone is on point with hand washing and other hygiene measures. 

Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital, wants the public to know that norovirus is even harder to eliminate than SARS-CoV-2: norovirus is very resistant to heat and cold, and it can also withstand alcohol. This is why handwashing, and washing items and surfaces with soap and water, is the most important measure to stop norovirus from spreading.

These are some measures any food handling team must implement to reduce the risk of starting a norovirus outbreak:

  • Do not allow sick employees to work or even enter the food operation.
  • Make sure every staff member frequently washes their hands with soap and water, since hand sanitizer is not effective against norovirus.
  • Avoid serving raw oysters or raw seafood if there is a norovirus spike
  • Cook seafood to at least 65°C
  • Wash fruits and vegetables thoroughly before preparing and serving them

Education is the best way to prevent making people sick with the food you prepare or serve. The Canadian Institute of Food Safety offers a highly regarded Food Handler Certification Course that meets all of Canada’s legal requirements for food safety training.