Flu symptoms? Data shows where in Canada influenza activity is ‘widespread’

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Newly published data shows cases of influenza in Canada are increasing, with the spread of the flu especially prevalent in certain parts of the country.

A respiratory surveillance update published Friday outlined the results of testing across Canada, highlighting that cases of influenza are increasing, based on testing conducted last week.

According to the federal report, the percentage of positive tests for influenza is now the highest Canada has seen since a previous peak at the beginning of the 2020-21 flu season.

‘Widespread’ flu activity

The results outlined in Friday’s FluWatch report shows some areas are being impacted more than others.

Flu activity classified as “widespread,” a threshold involving test-positive cases, as well as outbreaks at facilities under surveillance, was noted in 11 regions within four provinces. Those regions are labelled as: B.C.’s Vancouver Island, Vancouver Coastal, Fraser, Interior; Alberta’s South Zone; Ontario’s Central East and Toronto; Quebec’s Montreal et Laval, Ouest-du-Quebec, Centre-du-Quebec, and Quebec et Chaudieres-Appalaches.

These locations can be viewed on an interactive map and table on the FluWatch website.

At least some level of confirmed influenza activity has been reported in every province or territory in Canada except Nunavut, the report said.

Influenza A (H1N1)

A total of 11,790 tests came back positive for influenza last week, with the vast majority of patients found to have influenza A, which has so far been the more common infection this year. Only 7.4 per cent of last week’s positive tests reflected an infection of influenza B.

According to the U.S. Centers for Disease Control and Prevention, influenza A viruses are the only types of influenza “known to cause flu pandemics.” This season’s most common subtype of influenza A in Canada has been H1N1, also known as swine flu. The name may be familiar, as this subtype was responsible for millions of illnesses in 2009, during which the World Health Organization declared a pandemic.

The latest Canadian data suggests hospitalizations are increasing due to influenza, especially in patients aged 65 and older, but that the weekly hospitalization rate sits at 3.4 people per 100,000 population.

COVID-19 and RSV

This weekly surveillance also tracks cases of SARS-CoV-2 (COVID-19) and respiratory syncytial virus (RSV).

As mentioned earlier, last week’s testing showed increasing cases of influenza, but decreasing cases of COVID-19 and RSV. Just under five per cent of tests were positive for RSV, while four per cent were positive for COVID-19.

Those behind the report said the number of test-positive COVID-19 cases is the lowest its been in Canada since the start of the 2022-23 season.

Flu vs. cold: symptoms

The symptoms of the flu can be similar to those of the common cold, health authorities say.

Signs you have the flu include fever, cough, muscle or body aches, chills, tiredness, headaches, sore throat, loss of appetite and a runny or stuffy nose, according to Health Canada.

Some with the flu may also have diarrhea, nausea and vomiting.

The agency advises rest, drinking lots of fluids and over-the-counter medication to reduce fever or aches as treatment for the flu.

The U.S. CDC says symptoms of the common cold are usually milder, and people are more likely to have to deal with a runny or stuffy nose. Otherwise “it can be difficult (or even impossible) to tell the difference.”

Symptoms of RSV also have some overlap, including runny nose, coughing, sneezing and fever. People with RSV may also experience wheezing and decrease in appetite and energy.

The symptoms of COVID-19 vary depending on the person and the variant, Health Canada says, but can include sore throat, sneezing, runny nose, cough, shortness of breath, fever, chills, fatigue or weakness, muscle or body aches, loss of smell or taste, headache, abdominal pain, diarrhea, vomiting and “feeling very unwell.”