Public Health Alert – Increase in cases of iGAS

Published on 6 March 20256 March 2025

Situation

Northwestern Health Unit (NWHU) has seen an increase in invasive Group A Streptococcal (iGAS) disease cases in our region recently. The majority of cases have been identified in the Sioux Lookout (including Northern First Nations) and Kenora areas, but cases are occurring around the region. Cases are being seen in all age ranges, with most cases occurring in adults aged 25 and over. In Ontario, the NWHU catchment area continues to have one of the highest incidence rates, with 71.7 cases per 100,000 in 2024, while the Ontario incidence rate for the same year was 11.0.

Risk factors for recent cases have been consistent with local risk factors over time. These include having chronic illness or underlying medical conditions, wounds or dermatological conditions, diabetes, injection drug use, alcohol abuse, and homelessness or being underhoused.

Those at increased risk of iGAS include infants and young children; people who are pregnant or postpartum; older adults; and those who are immunocompromised. iGAS can progress very quickly and be associated with severe illness including sepsis, soft-tissue necrosis, streptococcal toxic shock syndrome, meningitis, pneumonia, or other life-threatening conditions resulting in death.

Actions requested

Prompt assessment and treatment of non-invasive GAS
Remain alert for signs and symptoms of iGAS, particularly for those at increased risk.
Educate patients on the signs and symptoms of serious bacterial infections and when to seek urgent medical attention.
Promote routine vaccinations including varicella, influenza, and Covid-19 for eligible patients. iGAS correlates with a recent viral illness, including chickenpox infection.

More information about iGAS in Ontario can be found on the Public Health Ontario website.

References

Contact:
Dr. Kit Young Hoon, MPH, MSc., FRCPC
Medical Officer of Health
Northwestern Health Unit

Public Health Alert – Increase in cases of iGAS Download