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Pandemics Throughout History

Pandemics Throughout History. A pandemic is defined as an unusually high outbreak of a new infectious disease that is spreading through the human population across a large region “pan” – all, “demos” – people.

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Pandemics Throughout History

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  1. Pandemics Throughout History

  2. A pandemic is defined as an unusually high outbreak of a new infectious disease that is spreading through the human population across a large region • “pan” – all, “demos” – people

  3. According to the World Health Organization (WHO), a pandemic can start when three conditions have been met: • emergence of a disease new to a population; • agents infect humans, causing serious illness; and • agents spread easily and sustainably among humans.

  4. Throughout human history there have been numerous pandemics, including the bubonic plague, smallpox, cholera, the Spanish influenza, and most recently HIV and H1N1 • Currently we are in experiencing flu outbreaks, the most recent, H5N1, is avian, as well as others:

  5. Global Alert Response Outbreak News 5 September 2012 Ebola (bats?) outbreak in Democratic Republic of Congo 4 September 2012 Hantavirus pulmonary syndrome (carried by rodents) – Yosemite National Park, USA 3 September 2012 Ebola in Uganda 30 August 2012 Ebola outbreak in DRC

  6. The Bubonic Plague (1347-1352) • Also known as the “Black Death” • Caused by a bacteria (Yersinia pestis) carried by rats and spread by fleas • Infectious agent: Yersinia pestis • Reservoir: rats • Vector: fleas • Kills within 3-7 days if untreated • Killed tens of millions across Europe (between ¼ and ½ of the total population)

  7. Cholera Pandemic (1817-1823) • A water-bourne bacteria, Vibrio cholerae causes severe diarrhea leading to dehydration and death • The first pandemic is characterized by the unprecedented spread of the bacteria throughout Asia, starting at the Lower Ganges River in India • Total estimated deaths: 30 000

  8. Spanish Influenza (1918-1920) • A very virulent influenza A subtype H1N1 strain • Approximately 1/3 of the world’s population became infected, and anywhere from 50 to 100 million people died worldwide (10-20% of those infected)

  9. WW I killed 15 mill., WWII 12 mill., Spanish flu 50 mill.

  10. HIV (1981-present) • From 1981 to 2006 AIDS killed more than 25 million people

  11. HIV (human immunodeficiency virus) is a retrovirus that can cause AIDS (acquired immunodeficiency syndrome) • It is thought to have originated in sub-Saharan Africa • HIV is passed through sexual relations, blood or blood products, and mother-to-child transmission

  12. The Flu

  13. Influenza is mainly a disease of water fowl H1-16\N1-9

  14. THE “SWINE FLU”: H1N1 (APRIL 2009 - 2010) • Caused by a strain of influenza A, H1N1 • Originated as a mixture of swine, avian, and human influenzas • The genetic change that allows a virus to “jump species” is called antigenic shift

  15. H3N8 H2N2 H2N2 H1N1 PandemicH1N1 H3N2 2015 2010 1915 1925 1955 1965 1975 1985 1995 2005 1895 1905 H1N1 H9* Recorded new avian influenzas 1999 H5 1997 2003 H7 1980 1996 2002 1955 1965 1975 1985 1995 2005 Pandemics of influenza Recorded human pandemic influenza(early sub-types inferred) 2009 Pandemic influenza H1N1 1889 Russian influenza H2N2 1968 Hong Kong influenza H3N2 1918 Spanish influenza H1N1 1900 Old Hong Kong influenza H3N8 1957 Asian influenza H2N2 Animated slide: Press space bar Reproduced and adapted (2009) with permission of Dr Masato Tashiro, Director, Center for Influenza Virus Research, National Institute of Infectious Diseases (NIID), Japan.

  16. Antigenic Drift Mutation in haemagglutinin RNA Haemagglutinin Neuraminidase Antibodies bind to haemagglutinin; inhibit infection Antibodies can no longer bind to haemagglutinin; infection and disease results

  17. Antigenic Shift Human and avian flu viruses infect same host cell (eg. swine); exchange of segments occurs New subtype of influenza with potential to cause a pandemic may be produced

  18. PB2 PB1 PB2 PA PB1 HA PA NP HA NA NP MP NA NS MP NS PB2 PB1 PA HA NP NA MP NS Genetic origins of the pandemic (H1N1) 2009 virus: viral reassortment N. American H1N1 (swine/avian/human) Eurasian swine H1N1 Pandemic (H1N1) 2009, combining swine, avian and human viral components Classical swine, N. American lineage Avian, N. American lineage Human seasonal H3N2 Eurasian swine lineage

  19. Clinicalsymptoms Asymptomatic Seasonal influenza compared to pandemic — proportions of types of cases Deaths Requiring hospitalisation Clinicalsymptoms Deaths Requiring hospitalisation Asymptomatic Seasonal influenza Pandemic

  20. WHAT WE KNOW ABOUT 2009 H1N1 • Infection rate for probable and confirmed cases highest in 5−24 year age group. • Hospitalisation rate highest in 0−4 year age group, followed by 5−24 year age group. • Pregnant women seem particularly at risk • Most deaths in 25−64 year age group in people with chronic underlying disease. (total about 300 000 world-wide, most in Africa and Southeastern Asia) • Adults, especially 60 years and old, may have some degree of preexisting protection • There are some predictions that up to 1/3 of the population could have become infected…

  21. Canada Flu Video

  22. What can we do to prepare ourselves for a pandemic?

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