Common killers and pandemicsEdit
According to the World Health Organization, a pandemic can start when three conditions have been met:
- the emergence of a disease new to the population.
- the agent infects humans, causing serious illness.
- the agent spreads easily and sustainably among humans.
A disease or condition is not a pandemic merely because it is widespread or kills many people; it must also be infectious. For example cancer is responsible for many deaths but is not considered a pandemic because the disease is not infectious (although certain causes of some types of cancer might be).
World Health Organization pandemic phasesEdit
The World Health Organization (WHO) has developed a plan to prepare globally the fight against influenza. It defines the stages of a pandemic and makes recommendations for national measures before and during a pandemic. The phases are:
- Phase 1: No new influenza virus subtypes have been detected in humans.
- Phase 2: No new influenza virus subtypes have been detected in humans, but an animal variant threatens human disease.
Pandemic alert period:
- Phase 3: Human infection(s) with a new subtype but no human-to-human spread.
- Phase 4: Small cluster(s) with limited localized human-to-human transmission
- Phase 5: Larger cluster(s) but human-to-human spread still localized.
- Phase 6: Pandemic: increased and sustained transmission in general population.
- Steward's "The Next Global Threat: Pandemic Influenza".