Ontario hospitals and pediatric physicians are being told to “be alert” for symptoms of invasive Group A Streptococcal Disease (iGAS) after an “increasing trend” has been identified.

In a memo obtained by CTV News Toronto, dated May 23, the province’s associate chief medical officer of health said an increase of cases had been reported in Ontario among all age groups, including children under the age of 18.

“Rates of illness are highest among those aged 0 to 4 and 65 years of age and older,” Barbara Yaffe wrote in the memo. “Others at increased risk include those with immunocompromising conditions, chickenpox, and people experiencing homelessness or who use injection drugs.

“In a recent report from the United States, some children with iGAS had preceding or concurrent respiratory viral infections.”

The memo was sent to emergency departments, labour and delivery units, and primary care organizations.

Group A Strep (GAS) is an infection caused by bacteria that spreads from person-to-person through direct contact with the nose, throat, respiratory droplets or wound secretions. The common non-invasive illnesses include strep throat, skin infections, such as impetigo, and scarlet fever.

It often can be treated with antibiotics.

According to Public Health Ontario, GAS becomes “invasive” when the bacteria enters the blood stream or deep tissue. The health agency says this can result in severe, life-threatening illness such as pneumonia, meningitis, septicemia, and other serious diseases.

Health-care providers are being asked to provide prompt assessment and treatments for non-invasive GAS, and to be alert for potential complications.

If invasive GAS is suspected, specimens should be collected for testing. Public health units should be notified of any cases and clusters, the memo says.

Public Health Ontario says 894 cases of iGAS were reported in the province between October 2022 and April 30, 2023.

The most recent report says an “increasing trend” of iGAS has been seen since January.

“The total number of iGAS cases reported in April 2023 is the highest monthly case count reported to date since the 2014/15 season,” the report, published in May, notes.

The majority of cases were found in individuals over the age of 18, however 45 children between the ages of one and four were also diagnosed with iGAS.

About 74 per cent of patients were hospitalized as a result.

Yaffe noted in the memo that officials are “closely monitoring the situation” and further updates will be provided if there are any new developments.