Lecture 23 : Assessment of Risks Overview

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Lecture 23 Assessment of Risks Overview

• EPIDEMIC DISEASES
• INFLUENZA

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Epidemic Diseases

• History shows that new diseases arriving as an
  epidemic can have a devastating impact.
• New diseases are being discovered every year.
• The threat posed by these new diseases is related
  to their means of transmission.
• Diseases spread by person to person contact pose
  a risk, but they are generally containable.
• Water- and food-borne infections can be contained
  with adequate public health measures.
• Vector-borne diseases are dependent on the
  availability of vectors. It is becoming more
  difficult to control vectors.
• Air-borne diseases pose the greatest threat.

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Influenza(1)

• Biggest threat may be influenza.
• Influenza viruses are classified into A, B and C
  strains. The A strain is further classified by
  its haemagglutinin and neuraminidase antigens,
  which mutate.
• 1957 Asian flu was A2 or H2N2, 1968 Hong Kong flu
  was A3 or H3N2.
• Influenza is found in birds, pigs and horses.
• The 1918 Spanish flu killed between 20 million
  and 100 million people worldwide.
• SARS in 2003 was initially thought to be a flu.

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Asiam Palm Civet
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Influenza(2)

• Avian flu H5N1 infected people in Vietnam in
  2004.
• Similar to the H5N1 strain in the Hong Kong
  outbreak in 1998, which was contained by culling
  the entire chicken population.
• Human cases low, and at present confined to
  people in close contact with chickens.
• Big fear is it could mutate into a human-human
  airborne infection.
• Effective vaccines may not be deployed for six
  months.
• With 63 per cent mortality, fear may cause all
  essential services to grind to a standstill.

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H5N1 Influenza Deaths (Birds and Humans)
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The End