PulseNet plays a vital role in the surveillance and investigation of foodborne illness outbreaks that were previously difficult to detect. Finding similar patterns through PulseNet, scientists can determine whether an outbreak is occurring, even if the affected persons are geographically far apart. Through PulseNet, outbreaks and their causes can be identified in a matter of hours rather than days.
Foodborne infections are an increasing global problem. The trade of raw and processed food across borders along with international travel makes it possible for human foodborne infections to originate in a different region than where the illness is observed. A standardized laboratory method permits inter-laboratory comparison and communication of information about foodborne illnesses, indicating a common source of food contamination.
PulseNet Canada Network
PulseNet is a critical surveillance system used to quickly identify and respond to foodborne disease outbreaks. We are a virtual electronic network which ties the public health laboratories of all provinces (plus some federal laboratories) together by linking their computers and databases. This national network is dedicated to tracking the DNA fingerprints of all cases of E. coli and most cases of salmonella.
The network is coordinated by the National Microbiology Laboratory (NML) located in Winnipeg, Manitoba. The PulseNet Canada team at NML houses and manages the national databases.
A critical component in the investigation of human foodborne outbreaks is the DNA "fingerprinting" of the causative organisms. These fingerprints are the DNA profiles of a human foodborne pathogen obtained by DNA characterization methods such as pulsed-field gel electrophoresis (PFGE).
Once these PFGE patterns are generated, they are entered into an electronic database of DNA fingerprints, which are available on-line to participants. This enables the rapid comparison of patterns allowing for the detection of geographically dispersed outbreaks of foodborne bacterial disease at an earlier stage compared to traditional laboratory surveillance. This allows for more timely interventions to outbreaks and reduced impact on public health.
- detect clusters of cases with matching DNA “fingerprints” (PFGE patterns)
- facilitate early identification and investigation of foodborne disease outbreaks
- assist in epidemiological investigations to differentiate outbreak from sporadic cases and the identify the source of outbreaks
- Provide a rapid communications platform and link public health laboratories across the nation
- Enteric bacterial pathogens are isolated from human clinical cases
- Molecular subtyping, pulsed-field gel electrophoresis (PFGE), is performed by participating laboratories using standardized methodology, equipment, and software.
- Molecular subtyping results are entered into electronic databases at the provincial and federal National Microbiology Laboratory (NML). Participating members are certified and have a direct link to the federal databases.
- Participating laboratories post clusters of cases with matching PFGE patterns in their jurisdictions to the PulseNet Canada discussion board on the Canadian Network for Public Health Intelligence. Members view and respond to postings on a daily basis.
- Database managers at NML search for clusters of indistinguishable patterns in more than one province; results are report to the participating lab(s), PHAC epidemiologists, and are posted to the discussion board.
The provinces and appropriate federal departments work very closely together monitoring food and waterborne pathogens that emerge anywhere across the country on an ongoing basis. Participating laboratories are:
History of PulseNet
PulseNet was first developed in the United State in response to a large outbreak of E. coli in 1993. During the outbreak, scientists at the Centers for Disease Control and Prevention (CDC, Atlanta, Georgia) performed DNA "fingerprinting" by PFGE and determined that the strain of E. coli found in patients had the same PFGE pattern as the strain found in hamburger patties served at a large chain of regional fast food restaurants. Prompt recognition of this outbreak led to the creation of PulseNet in the US.
PulseNet Canada was developed in 2000 to create a similar system for Canadians as well as to harmonize with PulseNet USA. Currently, the Canadian network includes the public health laboratories of all ten provinces plus two federal laboratories (the Public Health Agency of Canada's Laboratory for Foodborne Zoonoses and Health Canada's Bureau of Microbial Hazards).