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Epidemics and pandemics

Influenza pandemic


Epidemics and pandemics

A pandemic is the propagation on a global scale of a new illness to which the majority of the population does not have immunity.

Human influenza – also known as the flu – is a respiratory infection caused by the flu virus. Different strains of this virus circulate regularly, causing illness in our communities. However, you may not get sick if you have the antibody to fight the strain of the virus to which you were exposed. 

If a flu virus changes and becomes a new strain to which people  have little or no immunity, and the new strain spreads quickly from one person to another, many people across the world could get sick and die. This situation constitutes an influenza pandemic. This type of pandemic happens approximately three times per century.

The pandemic flue virus often causes major complications for healthy people, primarily pneumonia and death. The last three pandemics took place in 1918-1919, 1957-1958 and 1968-1969.

For more information : Canada Public Health Agency  

Preparing and protecting yourself

Risks in Montréal

The Influenza A H1N1 pandemic of 2009 showed that epidemics are managed on an international scale. With increased global travel, the epidemics caused by new flu viruses spread and become pandemics more quickly than ever before.

Montréal is not safe from this threat and has, in the past, been affected by many flu epidemics. The 1918 Spanish flu is one example, during which more than 3,500 Montrealers died from the illness over a period of a few months.

Montrealers can get general information about the risk of infections and pathogens on the Montréal director of Public health’s website (French only) and consult the flu index on the Weather Network’s Web site

Impacts on the population and infrastructures

  • Increased mortality rate
  • Perceptions and fears of residents
  • Increased worker absenteeism
  • Difficulty in offering essential services to the population as well as minimal emergency services (police, firefighters, health care)
  • Difficulty for providers to ensure delivery of essential goods and services (oil, maintenance and repairs of rolling stock, etc.)
  • Interruption of certain food supplies, such as difficulties importing and exporting food.
  • Economic impacts (decreased tourism, cancellation of major and international events) and socio-economic disorganization.

Types of viruses

Flu A (H1N1)

Influenza A (H1N1) has spread all over the world. The A virus (H1N1) is a flu strain that previously only affected swine. In spring 2009, the virus appeared in the North American population and spread all over the world. The strain was new and human beings had little or no natural immunity to it. The World Health Organization declared an Influenza A (H1N1) pandemic in June 2009.

Source : Public Health Agency of Canada

Bird Flu A (H5N1)

Bird flu is a contagious virus among bird species which, rarely, can spread to mammals. In January 2004, there was an influx of Influenza A (H5N1), commonly known as bird flu. To reach the level of a pandemic, a virus has to spread from one human to another. This level was not reached in 2005 and in Québec, no cases of H5N1 were registered by public health authorities. However, a great deal of work was done to create a special response plan for flu pandemics.

Source : Public Health Agency of Canada

West Nile virus

The West Nile is a region in central Africa where this virus first appeared more than 60 years ago. The virus was then detected in many other parts of the world, mainly the Middle East, Asia and Europe.  In 1999, it was detected in New York City – its first appearance in North America, Since then, it has continued to spread. In Montréal, the West Nile virus has not represented a risk of pandemic or epidemic for several years.

Source : Public Health Agency of Canada


Severe acute respiratory syndrome (SARS) is a respiratory illness that spreads through close contact with an infected person. Close contact includes living in the same house or caring for someone with SARS, or direct contact with respiratory secretions or bodily fluids of an infected person.

Source : Health Canada

Influenza pandemic special response plan

Indicators and actions

How OSCAM (Montreal agglomeration civil protection organization) implements alert and mobilization levels is determined by the orientations of the ASSS (Montreal health and social services agency), which in turn determines its actions according to the World Health Organization (WHO). Actions taken by the CSC and its partners depend on the level of mobilization. 

Phase 4
Pandemic alert
Charactarized by human to human transmission of a flu virus that could cause “outbreaks on a community scale.”  Phase 4 indicates a heightened risk of pandemic but does not necessarily mean that a pandemic is inevitable.
  • Passive watch for animal and human cases outside Québec
  • Active watch for animal and human cases within Québec
Phase 5
Pandemic alert
When at least two countries in the same WHO region are affected and the virus spreads from one person to another. Phase 5 indicates that a pandemic is imminent and mitigative measures must be implemented.
Pre-alert and active watch
  • Montreal’s plan to fight flu pandemic is updated and implemented
  • Information to partners about health ministry directives and the status of the global, national and municipal epidemiological situation. 
  • Influenza pandemic special response plan updated
Phase 6
Also known as the pandemic phase, phase 6 is characterized by outbreaks on a community level in at least one country in another WHO region, in addition to the criteria listed in phase 5. The declaration of this phase means a world pandemic is underway.
(once the pandemic is confirmed regionally)
  • Network alerted once WHO announces phase 6 
  • Develop recommendations and advice concerning provention and protective equipment to use, depending on level of exposure.
Watch or Alert
(depending on virulence of the virus)
  • Monitor the integration of health ministry’s recommendations (such as wearing face masks, distribution of antiviral drugs, vaccinations, etc.)   recommandations du
  • Monitor delivery of essential activities
(as soon as the pandemic is regionally confirmed)
  • Collect surveillance data
  • Identify priority groups to vaccinate 
  • Monitor directives concerning prohibition of large gatherings and closing of public places
  • Consolidation of human resources for essential activities
  • Implementation of succession planning strategy

Important Numbers

Health Info
Transports Québec
City information

Poison center

24 hours a day, 7 days a week 1-800-463-5060