Canada's public health agency has reported a record number of cases involving an aggressive and potentially fatal form of strep, particularly in children under the age of 15. 

Almost 50 people in Ontario, including six children, died from invasive Group A Streptococcal Disease (iGAS) between Oct. 1 and Dec. 31, 2023. 

The infection can result in severe, life-threatening conditions, such as pneumonia, septicemia, Streptococcal Toxic Shock Syndrome, and necrotizing fasciitis (flesh-eating disease). 

As of Jan. 9, the Public Health Agency of Canada's (PHAC) National Microbiology Laboratory recorded more than 4,600 samples of the bacteria in 2023, which is the highest annual total recorded. 

In recent years, PHAC says 2,000 to 3,000 cases have been reported annually, with the latest peak occurring in 2019, with 3,236 samples of the bacteria logged. In Ontario, 222 confirmed cases were logged in December 2023, more than any other month on record. 

Between Oct. 1 and Dec. 1, there were 540 confirmed iGAS cases in Ontario, with 74 per cent of those cases hospitalized and 48 deaths. 

"This is higher than the proportion of iGAS cases within the same age group that had a fatal outcome reported in the same reporting period for the previous season, and exactly half of the total number of pediatric deaths reported in the entire 2022-23 season," Public Health Ontario wrote in a Jan. 11 report. 

According to Public Health Ontario, the disease is caused by bacteria that spread person-to-person through direct contact with the nose, throat, wound secretions, or respiratory droplets. 

In rare cases, the bacteria becomes invasive and enters parts of the body, such as blood, deep muscle, fat tissue, or the lungs. Health conditions that decrease a person's immunity to infection also make the invasive disease more likely.

Prevention includes washing hands well — especially after coughing and sneezing and before preparing foods or eating — keeping all cuts and wounds clean, and watching for possible signs of infection such as redness, swelling, drainage, and pain at the wound site.