Measles: Monitoring

How Canada monitors measles

As a nationally reportable disease in Canada, surveillance of measles is conducted by public health professionals in provinces and territories. They report cases to the Government of Canada (GC) through systems at the federal level.

Cases are reported by health care providers to public health units if the patient:

• presents with symptoms and are laboratory-confirmed
• has a known link to a laboratory-confirmed case

Consult the national case definition for additional information.

National enhanced surveillance of measles is conducted through the Canadian Measles/Rubella Surveillance System (CMRSS). This system involves weekly collection of enhanced measles data from all provinces and territories. This allows timely monitoring of measles elimination in Canada.

Genotype surveillance is conducted by the National Microbiology Laboratory (NML). The laboratory is a World Health Organization and Pan American Health Organization-accredited measles and rubella regional reference laboratory. Genotyping is an important tool in measles surveillance for 2 key reasons:

• it is the only way to distinguish clinical illness due to vaccine, as opposed to a wild-type measles virus infection
• it allows for the differentiation between chains of measles transmission

Genotype results from the NML are incorporated into CMRSS.

Measles cases are summarized annually in the Canadian Notifiable Disease Surveillance System.

In addition, the Measles and Rubella Weekly Monitoring Report summarizes the information collected through the CMRSS and MARS surveillance systems on a weekly basis.

For more information on measles epidemiology, transmission, prevention and control, refer to the For health professionals section.