Quebec monitoring rise in walking pneumonia cases among children

Quebec's Health Ministry says it is monitoring a rise in respiratory infections among children and teenagers in the province caused by a bacterium associated with walking pneumonia.

In a statement, the ministry says it has received "signals indicating increased circulation" of the bacterium and is working with health and social services partners to track the situation.

The bacterium is mycoplasma pneumoniae. According to Health Canada, the majority of infections in adults are asymptomatic, but it may cause upper respiratory tract infections in up to 50 per cent of cases. Symptoms can be severe in the elderly or immunocompromised.

Symptoms develop over several days and persist for weeks to months, with common symptoms including sore throat, hoarseness, fever and cough. Progression to pneumonia is rare for children under five years of age, but common for those between five and 15 years old, Health Canada says.

Mycoplasma pneumoniae is responsible for up to 40 per cent of community-acquired cases of pneumonia in children over five years old.

A spokesperson for Montreal's Sainte-Justine Hospital, a pediatric hospital centre, says 2,025 emergency room patients were diagnosed with walking pneumonia between April 1 and Nov. 16.

Compared to roughly the same time period last year, there were only 935 patients diagnosed with the disease, the spokesperson, Danika Landry, said in an email. 

"This year, we are seeing significant growth starting at the end of August," she said.

The data from Sainte-Justine reflects the broader increase in transmission rates noted by the province.

The ministry says that, while there is no mandatory reporting for mycoplasma pneumoniae infections in Quebec, data for 2024 shows higher transmission rates among people aged 17 and under compared to previous years.

The ministry also pointed to the cyclical nature of the infection, with significant peaks recorded in 2015, 2019 and 2024. According to federal data, mycoplasma pneumoniae outbreaks tend to occur every three to five years.

The statement says the bacterium is found worldwide and Quebec clinicians have access to several diagnostic tests to identify the pathogen.