ARCHIVED - 3.0 Surveillance of Invasive GAS Disease in Canada

Invasive GAS infection is reportable in every province and territory (P/T) in Canada. Most jurisdictions rely on passive surveillance for identification of cases. Each P/T has procedures in place for the rapid notification of cases to medical officers of health and timely reporting to the appropriate P/T public health official. Readers should refer to the case definitions specified by their respective P/T jurisdictions for the purposes of local reporting.

S. pyogenes is a Gram-positive coccus, which occurs as pairs or as chains of short to moderate size(7). Invasive GAS disease is confirmed through laboratory testing of specimens taken from normally sterile sites. Local microbiology laboratories perform antibiotic susceptibility testing for clinical purposes, whereas the National Centre for Streptococcus (NCS) conducts susceptibility testing for surveillance purposes only. Some provincial public health laboratories and academic reference laboratories may perform specific molecular analyses in support of outbreak investigations; however, the NCS is the only laboratory in Canada that performs M protein typing and emm gene sequencing of S. pyogenes isolates for routine surveillance. Serotyping, molecular sequencing and antimicrobial susceptibility testing are helpful in characterizing outbreaks, determining disease trends and guiding appropriate clinical management of cases and contacts. Annex 2 provides further details on laboratory support for outbreak investigation of invasive GAS disease.

Only confirmed cases of invasive GAS disease are notifiable at the national level. Currently, some P/Ts report case-by-case data with basic core variables on a monthly basis to the Notifiable Diseases Reporting System, and others report aggregate data by age, sex and month of episode.