Transcript Infuenza Power Point

THE QUESTION:
SHOULD I GET A FLU SHOT
EACH YEAR?
“KILLER FLU”
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LEADING CAUSES OF DEATH, UNITED STATES, 1995
Rank
Condition Number of Deaths
1
Heart Disease
737,563
2
Cancer
538,455
3
Cerebrovascular disease
157,991
4
Chronic obstructive lung disease
102,899
5
Unintentional injury
93,320
6
Pneumonia and Influenza
82,923
7
Diabetes
59,254
8
HIV and AIDS
43,115
9
Suicide
31,284
10
Chronic liver diseases
25,222
Modified from: National Center for Health Statistics, Health, United
States, 1996-97 and Injury Chartbook, Hyattsville, Maryland: 1997
p.117.
What Causes the Flu?
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Click on the link below
and scroll down to the
influenza virus graphic
Where are the
Hemagglutinin receptors
on the virus?
What type of nuclear
material do you find in the
‘flu’ virus?
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Flu Graphic
Can you find the binding
sites on the Hemagglutinin
receptor?
What cells in your body
does this virus like to
enter?
How does the virus enter
cells?
What happens inside the
host cell?
Susceptibility, symptoms and
spread
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How is the virus spread?
What are the symptoms of
the flu?
Is there a sector of the
population more
susceptible to death upon
infection?
What might the economic
impact of influenza virus
be?
Influenza
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Open the “weekly
pneumonia and influenza
mortality chart”.
Discuss the significance of
the peaks in this graph.
How might this graph be
different if it was
monitoring mortality as a
% of Australian deaths?
Factors Affecting the Spread of
Influenza
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Use the Influenza simulation model to explore
factors that affect the spread of Influenza within
populations.
Simulation Model
Mac users must open this in Safari
click here and then select flu_sim.ppt from
the attachments menu for simulation instructions
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What recommendations can you propose to
control the spread of Influenza in a population?
Should we monitor Influenza virus affecting other
animals such as pigs and chickens?
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Update on avian influenza in Asia (17.03.04)
The avian influenza outbreak has claimed its 8th victim in
Thailand a 39-year-old factory worker who contracted the deadly
virus from a neighbor's sick fighting cocks, the health ministry
said on Tue 16 Mar 2004. The woman died last Friday, 12 days
after she was initially treated for diarrhea, the ministry said in a
statement. This 8th death in Thailand brings the total number of
human fatalities from avian influenza A (H5N1) virus infection in
East Asia to 23. There have been 11 laboratory-confirmed cases
of infection in Thailand and 22 confirmed cases in Viet Nam,
making the overall total 33. So far 15 of the Vietnamese cases
have died.
From: ProMED-mail Source: Reuters News online, Tue 16 Mar
2004 [edited].
Discuss methods that authorities
could employ to control the
spread of virus between animals
and humans?
Mutations in the
Hemagglutinin gene
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No antigenic shifts occurred between 1957 ("Hong Kong") and
1968 ("Asian"). So what accounts for the epidemics of 1962 and
1964?
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Missense mutations in the hemagglutinin (H) gene.
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Flu infections create a strong antibody response. After a
pandemic or major epidemic, most people will be immune to the
virus strain that caused it. The flu virus has two options:
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wait until a new crop of susceptible young people comes along
change the epitopes on the hemagglutinin molecule so that they
are no longer recognized by the antibodies circulating in the
bodies of previous victims.
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Evading the Immune System
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Evading Immunity
Read about evading immunity, shift and drift, to discover
why we don’t keep immunity against the influenza virus.
Discuss weather shift or drift in influenza is of major
concern to flu watch centres and health organisations
around the world?
View the animation: Genetic reassortment between human
and nonhuman influenza A viruses. Discuss the
significance of this event for human populations.
Why get a flu shot every year?
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You are a member of a
vaccine development
team. Brainstorm the
issues and strategies
involved in preparing
this years vaccine
Use the World Health
Organisation site for
guidance
WHO
Exploring the Genome for
Influenza
A
SINGAP ORE
6
86
Type of
Town where first
Number of Year of
Major type of HA and
Influenza
isolated
isolates
NA
isolation
H1N1
When viruses are isolated and sequenced,
scientists submit the information into libraries such
as GenBank. Nomenclature is based on the
parameters shown in the table above.
Phylogenetic Trees
Scientists analyse nucleotide sequences of
influenza strains to construct phylogenetic trees
and study relationships between these strains
Use the phylogenetic tree for influenza A on the following
page to discuss the following questions.
Which strain of influenza A is more closely related to
the A/Scotland/122/2001 strain? A/Beijing/262/95 OR
A/HongKong/52/95
How would phylogenetic trees assist health
organisations to prepare influenza vaccines?
Phylogenetic tree of influenza A
H1N1 and H1N2 virus HA1
nucleotide sequences
Constructing Your Own Tree
Use Phylogenetic Tree Constructor to explore
Hemagglutinin nucleotide sequences from
Human influenza virus, Chicken infuenza
virus and pig influenza virus
Phylogenetic Tree Constructor
View data set
Still to come….
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Using BLAST to compare and contrast
nucleotide sequences for human influenza A
H1N1 from the 1918 epidemic and from a
2003 isolate
Translating Nucleotide Sequences
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The nucleotide
sequence on the right
is a fragment of the
Hemagglutinin gene.
Use the codon table to
crack the code and
find the protein
sequence.
http://www.zerobio.com/toxin/codon.htm
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AAACAACTCAACCGA
CACTGTTGACACAGT
ACTTGAGAAAAACGT
GACAGTGACACACTC
AGTCAACCTACTTGA
GAACAGTCA
Now from the second
nucleotide. Does the
amino acid sequence
change?
Translating the Hemagglutinin Gene
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Use Biology Workbench to find the
complete amino acid sequence for the
Hemagglutinin gene.
Translation Instructions
Biology Workbench
Still to come…..
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Compare and contrast Hemagglutinin
structure in CN-3D