Biology, a single science

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Biology, a single science

• Good Luck !

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Suggested reading.

• New scientist
• Guardian/ Times/Telegraph when are their science
  days?
• When issuedthe Biology dept text Biology by
  Jones and Jones.

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BIOLOGY EXTENSION WORK

• MICRO- ORGANISMS AND DISEASE IN HUMANS
• THE SPREAD AND CONTROL OF DISEASE
• BIOTECHNOLOGY- USES OF MICROBES
• GENE TECHNOLOGY.
• MANIPULATION OF REPRODUCTION

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MICRO ORGANISMS AND DISEASE IN HUMANS

• A VIRUS- How does it differ to a cell?

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Viruses.

• Viruses have a protein coat called a CAPSID
• The capsid surrounds a nucleic acid either DNA
  or RNA. (RNA in case of the Flu virus)
• May also be surrounded by an envelope of lipid
  protein, this has been made from living cell in
  which it has reproduced.
• Outside a cell viruses remain INERT, need living
  cells to help them reproduce.
• Q Why are they not considered cells? Alive?

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Viruses when compared and contrasted with cells.

• Viruses do not contain nuclei or cytoplasm
• Demonstrates none of the characteristics of
  living things.
• Viruses contain either RNA or DNA cells contain
  both.
• Cells contain RNA and DNA so do viruses.
• Viral membranes made of lipids/ proteins.

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IMPORTANCE of RNA in Influenza virus? When RNA
enters another cell it can use cells own RNA
building blocks to make more of its own RNA. RNA
building blocks would be in cell ready to
instruct cell to make amino acid chain into
protein Virus RNA can instruct virus to make
protein coat
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How can such a simple structure invade and
multiply?
Brainstorm..
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Influenza, symptoms

• Temperature.(104 F, ..C)
• Sudden headaches
• Muscular aches
• Extreme exhaustion

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Means of transmission? How is it passed on?

• The influenza virus is a viral PATHOGEN
• Defn?
• A pathogen in an organism that invades a body and
  reproduces in it.
• Influenza is passed on by air droplets, can be
  passed on by coughing over someone, sneezing over
  them. Can animals pass FLU on?

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SPANISH FLU in 1918

• 40-45 million died in the most devastation plague
  in human history.
• It was a PANDEMIC definition?
• No one knew what caused the infection in 1918.
  Why do we know more now about viruses? Brainstorm
• Now scientists are investigating the GENOME of
  the virus. Why?

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Spanish flu prevention of transmission. What
was suggested? Would this work today?
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Spanish Flu Preventation of transmission? what
was suggested?
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SPANISH FLU

• Dateline 02/12/98
• Scientists announced a startling revelation last
  week the frozen body of a Native American
  female, found in a village in Alaska, was found
  to contain in its lungs traces of the virus that
  caused the flu epidemic of 1918.
• Scientists were able to decipher the genetic
  information of the virus from these remnants.
  Until now, partial sequencing had occurred, but
  the virus had never been fully recovered from
  body tissue.

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How bad was Spanish Flu? How can we avoid it in
the future?

• As their lungs filled the patients became
  short of breath and increasingly cyanotic. After
  gasping for several hours they became delirious
  and incontinent, and many died struggling to
  clear their airways of a blood-tinged froth that
  sometimes gushed from their nose and mouth. It
  was a dreadful business.
• Isaac Starr, 3rd year medical student,
  University of Pennsylvania, 1918.

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The future?

• A challenge to the students
• How can knowledge of the past help the
  future?
• Do we need to take care over the reservoir
  of the flu virus in animals?

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Other outbreaks

• 1957 Asian flu -
• http//money.cnn.com/2003/04/01/news/international
  /trips_flu
• 1968 Hong Kong Flu-http//news.bbc.co.uk/2/hi/hea
  lth/2846243.stm
• 
  http//biology.about.com/libra
  ry/weekly/aa020598.htm

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ASIAN FLU extract from a newspaper 1957

• The so-called 'Asian Flu' pandemic has killed
  thousands of people around the globe - many of
  them in the United States.
• The virus is believed to have originated in North
  China in February before spreading worldwide. It
  reached the UK three months ago.
• The vaccine, which is being produced at the
  Wright-Fleming Institute of Microbiology in west
  London, will be distributed free on the National
  Health Service.
• To give the fullest protection against the flu
  strain two injections are needed at an interval
  of not less than three weeks.
• Tens of thousands of units of the vaccine have
  been produced during the last two months,
  however, there is still not enough at present for
  everyone to be vaccinated.
• Brainstorm..
• How has production rate been increased since
  then? Would todays society accept the fact that
  there is not enough vaccine stored to prevent a
  viral epidemic?

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HONG KONG FLU
The key case involved an American businessman
who died on Thursday morning in a Hong Kong
hospital. He had arrived into Hanoi in Vietnam
from Shanghai on a business trip already
suffering from severe respiratory
problems Where had the disease originated from?
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HONG KONG FLU

• How deadly was it?
• Even with the advantages of intensive-care
  treatment, fully one third of the first 18
  confirmed cases never recovered. They died.
• The numbers are suggestive of the death tolls
  suffered by immunologically-isolated Alaskan
  villages in 1918.
• In Hong Kong, bird-to-human contact is
  believed to have been the transmission route.
  Fearing a public health crisis, city officials in
  December of 1997 ordered the slaughter of Hong
  Kong's entire poultry population. All ducks,
  geese, and chickens in the city were killed.
  Fortunately it appears the H5N1 subtype lacks the
  ability to transmit itself through the air from
  one human host to the next potential victim.

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• FACTORS INFLUENCING SPREAD OF INFLUENZA
• Size and accessibility of animal reservoir
  
• Global warming could impact influenza
  transmission in several ways.
• Changes in transportation,
• Level of availability and success of
  vaccine
• Changes in urbanisation? Cases of
  influenza outbreaks in August and early September
  have been reported, is this related to air
  conditioning?

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Influenza virus transmission between species and
relevance to emergence of the next human
pandemic. Webster RG.Although influenza
viruses are not spread from human to human
through the conventional food chain, this is not
necessarily the case for the transmission of the
precursors of the human pandemic influenza
viruses. Aquatic birds of the world are the
reservoirs for all influenza A viruses the virus
is spread by fecal-oral transmission in untreated
water. Influenza A viruses are frequently
transmitted to domestic poultry and two of the 15
subtypes H5 and H7 can become highly pathogenic
and have the capacity to decimate commercial
poultry flocks. Less frequently, avian influenza
viruses are transmitted between species-to pigs,
horses and sea mammals. This transmission
involves mutational, reassortant or
recombinational events and can occur through
fecal contamination of unprocessed avian protein
or through the water. The transmission of avian
influenza viruses or virus genes to humans is
postulated to occur through pigs that act as the
intermediate host. It is believed to occur by
airborne transmission. Once avian influenza
viruses are established in mammals, they are
transmitted from animal to animal by the
respiratory airborne route. The transmission of
avian influenza virus from their reservoir in
wild aquatic birds to domestic poultry and to
mammalian species including humans can be
prevented by treatment of the water supply and of
avian protein sources with disinfectants or by
heating. Agricultural authorities have
recommended the separation of wild aquatic and
domestic poultry and of pig and poultry farming.
It is theoretically possible to reduce the
possibility of the next pandemic of influenza in
humans by changes in agricultural practices so
that ducks are separated from pigs and
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Why would global warming influence spread of
influenza?

• Warmer weather reduces indoor crowding, which
  means reduction of virus transmission
• Higher relative humidity and ultraviolet flux
  could impair virus survival and slow the spread
  of disease.
• Warming may change bird migration patterns for
  interaction between humans and infected animals.

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Can we isolate victims?
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Cases of flu in September?

• September? a time unusual for transmission in the
  temperate zone. The outbreaks had in common
  shared living areas and shared air conditioned
  air. Common factors associated with influenza are
  crowding and low humidity. The new habitat of
  large air conditioned areas may predispose to
  influenza transmission outside the expected
  period. Outbreaks that occurred on cruise ships
  have shown that flu can be introduced from the
  Southern Hemisphere (Australia) and lead to
  outbreaks even in the middle of the summer.

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QUESTIONS

• Draw and label an electron microscope picture of
  an Influenza virus.
• Explain how influenza is caused, what are its
  symptoms?
• How is flu passed from person to person? How can
  this be prevented in the modern world?
• How has a knowledge of the past helped in modern
  day knowledge of influenza prevention?
• Future work, how is a vaccine created?