This explainer will be expanded continuously as information on the Type A H1N1 Flu Pandemic becomes available.
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These are the technical definitions of the phases and the Planned US Federal Government response.
20th Century Pandemics
1917 Pandemic — La Gripe Espanola or the “Spanish Flu”. 50 million or more died in the 1918 pandemic, up to 200,000 in the US. Some 30% of the world’s population of 1.5 billion were infected.
1957 Pandemic — The “Asian Flu” originated in China. It had two major waves killing some 2 million people.
1968 Pandemic — The “Hong Kong Flu” spread globally for two years resulting in about 1 million deaths.
1976 faux Pandemic — First identified at Ft. Dix, NJ in a new recruit, the pandemic never unfolded. The massive US immunization program resulted in about 500 cases of Guillain-Barre syndrome, a neurological condition that can be fatal. About fifty deaths were reported.
CDC — Centers for Disease Control and Prevention. Located in Atlanta, Georgia, the CDC is part of the US Department of Health and Human Services.
Close Contact – One meter (about three feet) is often cited by infection control professionals to define close contact (based on studies of respiratory infections); for practical purposes, this distance may range up to 2 meters (six feet). The World Health Organization says approximately one meter; the U.S. Occupational Safety and Health Administration guidlelines state within 6 feet”.
Epidemic — A disease occurring suddenly in humans in a community, region or country in numbers clearly in excess of normal.
Facemask — A disposable mask cleared by the U.S. Food and Drug Administration (FDA) for use as a medical device. Facemasks have several designs. Held in place two ties, conforms to the face with the aid of a flexible adjustment for the nose bridge, and may be flat/pleated or duck-billed in shape; pre-molded, attached a single elastic band, and has a flexible adjustment for the nose bridge; and flat/pleated and attached with ear loops. Facemasks cleared by the FDA for use as medical devices have been determined to have specific levels of protection from penetration of blood and body fluids.
Ground Zero — The location where the first case occurred. The earliest confirmed case of the influenz A H1N1 has been traced to the village of La Gloria in Veracruz, Mexico located south east of Mexico City.
H1N1 — See Influenza A H1N1.
Influenza — A serious disease caused by viruses that infects the upper respiratory tract.
(Electron Microscope image of Influenza A H1N1 virus.)
Influenza A (H1N1) — The official name of what is commonly but inaccurately called ‘swine flu”. The strain consists of four elements, one human, one avian, and two swine. The World Health Organization began using this nomenclature on April 30, 2009.
Influenza Pandemic — A global outbreak of a new influenza ‘A’ virus that is easily transmitted from person-to-person worldwide.
Mutating Virus — In general, any flu virus mutates and evolves mechanisms that enable it to escape the immune defence systems of its victims.
Pandemic — The global outbreak of a disease in humans in numbers clearly in excess of normal.
Pandemic Phases — WHO has divided pandemics into six phases. (See Figure above.)
Pandemic Phase 1 — Low risk of human cases. No viruses circulating among animals have been reported to cause infections in humans.
Pandemic Phase 2 — Higher risk of human cases. An animal influenza virus circulating among domesticated or wild animals is known to have caused infection in humans, and is therefore considered a potential pandemic threat.
Pandemic Phase 3 — No or very limited human-to-human transmission. An animal or human-animal influenza reassortant virus has caused sporadic cases or small clusters of disease in people, but has not resulted in human-to-human transmission sufficient to sustain community-level outbreaks. Limited human-to-human transmission may occur under some circumstances, for example, when there is close contact between an infected person and an unprotected caregiver. However, limited transmission under such restricted circumstances does not indicate that the virus has gained the level of transmissibility among humans necessary to cause a pandemic.
Pandemic Phase 4 — Evidence of increased human-to-human transmission. Human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause “community-level outbreaks.” The ability to cause sustained disease outbreaks in a community marks a significant upwards shift in the risk for a pandemic. Any country that suspects or has verified such an event should urgently consult with WHO so that the situation can be jointly assessed and a decision made by the affected country if implementation of a rapid pandemic containment operation is warranted. Phase 4 indicates a significant increase in risk of a pandemic.
Pandemic Phase 5 — Evidence of significant human-to-human transmission. Human-to-human spread of the virus into at least two countries in one WHO region (Figure 4). While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalize the organization, communication, and implementation of the planned mitigation measures is short.
Pandemic Phase 6 — Efficient and sustained human-to-human transmission. The pandemic phase is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way. [Editor’s Note: According to these stated criteria, the pandemic phase has already reached pandemic phase 6 on April 30, 2009.]
Respirator — Refers to an N95 or higher filtering facepiece respirator certified by the U.S. National Institute for Occupational Safety and Health (NIOSH).
rRT-PCR Swine Flu Panel diagnostic test – A tool used to diagnose swine flu cases locally, thus speeding up the confirmation process.
Spanish Flu — Another name for the 1918 flu pandemic or La Gripe Espanola.
Swine Flu — Commonly used shorthand name for influenza A (H1N1) Symptoms — Body aches, fever, headaches, sore throat, body pain, chills and fatigue, and sometimes diarrhea and vomiting.
Tamiflu and Relenza — In response to the request from CDC, The U.S. Food and Drug Administration , in has issued Emergency Use Authorizations for the use of Relenza and Tamiflu antiviral products. Tamiflu has been stockpiled by Homeland Security in the US. For optimum efficacy, infected individuals should take it as early as possible. It lessens the symptoms but is not a cure for Swine Flu.
WHO — Located in Geneva, Switzerland, the World Health Organization, is the directing and coordinating authority for health within the United Nations system.