Transcript HIGHER GEOGRAPHY PAPER 2 DEVELOPMENT AND HEALTH

HIGHER GEOGRAPHY
DEVELOPMENT AND HEALTH
MALARIA – A WaterRelated Disease
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1. THE CAUSE
2. THE EFFECTS
3. THE RISK FACTORS
4. THE SOLUTIONS
5. KEY REVISION POINTS
1. THE CAUSE
MALARIA TODAY…

Global population at risk - 2.3 billion people - about 40%
of the world’s population

Number infected - 500 - 600 million people

Global annual mortality - 1.5 - 3 million deaths, or
between 4000 and 8000 each day

In the time it takes to say the word malaria, ten people,
seven of them children, will have caught it.

Every 30 seconds, a child dies of malaria.
After dropping
steeply between
1930 and 1970,
malaria is now
making a real
comeback,
especially in
Africa, south of
the Sahara, where
90% of all deaths
occur.
Background
The name comes from the
Italian mal (bad) and aria (air)
– it was originally thought the
disease was spread by the
damp air from swamps.
The link between the disease and
the Anopheles Mosquito was first
made by Ronald Ross, a Scottish
army doctor, working in India.
It is predominantly a
disease of the Tropics.
Malaria is a disease which is endemic in many
countries – this means it is always present.
…with global warming,
however, malaria may be closer
than you think…
INFECTION
You can catch Malaria from blood
transfusions,
 …or infected needles,
 …or intra placentally i.e from a mother to the
baby in her womb.

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But by far the most common way is by being
bitten by the female Anopheles Mosquito.
When the Anopheles Mosquito “bites”, it
actually sinks a long, thin mouth part, the
proboscis, into the skin.
The mosquito then pumps saliva under the skin, to
stop the blood clotting – so that it can drink
uninterrupted! In the saliva is the main culprit, the
Plasmodium, a single-cell blood parasite.
PLASMODIUM – 4 MAIN SPECIES

Plasmodium ovale

Plasmodium vivax

Plasmodium malariae

Plasmodium Falciparum – the most deadly.
If the mosquito is carrying the
Plasmodium, then it will transfer it to the
victim’s bloodstream in its saliva.
If the person is infected, then they will transfer
the Plasmodium into the mosquito, which can
then fly off and infect someone else.
Mosquito larvae hang from the surface tension of
the water, breathing through their siphon tube.
A jar containing mosquito larvae.
Pupae ready to hatch into adult mosquitoes
An adult
emerges, the
males to look
for plant
nectar, the
females for
blood.
Back to
CHOICES
2. THE EFFECTS
INFECTION
Several days of
headaches and
vague, flu-like
pains of the
body…
Several days
of weakness
and slow
recovery
Sudden onset of cold stage
– patient shivers violently
and turns blue with cold,
even though his actual
temperature is rising. Lasts
about one hour…
Sweating stage
patient soaked in
sweat, but begins
to feel better after
2-3 hours…
Hot stage – high
temperature,
headache, sickness
and dizziness. Lasts
several hours…
Millions of red blood cells are destroyed in an attack of malaria.
A remarkable
close-up of
destroyed red
blood cells.
Falciparum malaria - blood vessels to the brain are
blocked with dead red blood cells, starving the brain of
oxygen. Coma or death will follow rapidly.
Most at risk are the very young, who have not yet
developed any degree of natural immunity…
…along with pregnant women,
whose immune system is weakened.
A young victim of Falciparum Malaria
…and another
Without rapid medical help, many of these children
will die: currently one every 30 seconds or less.
Adult victims will have
repeated attacks for
many years, unless
treated. When ill, they
cannot work.
THE COSTS

The huge cost in terms of human
suffering: 1 – 3 million deaths a year.
Hundreds of millions ill.

Massive impact on attendance of children
at school. Education suffers.

Large numbers unable to farm their land
or collect in the harvest. The harvest
coincides with the peak biting season for
mosquitoes.
THE COSTS
Enormous financial cost to families to buy anti
malarial medicines. In some cases 25% of their
annual income. This is on top of paying
preventative costs and lost income.
 Over $2 billion dollars spent on fighting the
disease in Africa alone, money which could be
spent on development.
 Africa’s GDP would be $100 billion greater if
malaria had been wiped out thirty five years ago.
 Tourists and foreign investors avoid malaria
ridden areas.

Back to CHOICES
3. THE RISK FACTORS
MALARIA - RISK FACTORS - 1
ENVIRONMENTAL
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The presence of Anopheles mosquitoes
The presence of the plasmodium, in either the
mosquitoes or human population.
A warm, humid climate - temperatures between
16°C and 40°C and abundant rainfall.
Areas of still / standing water. Only a tiny area of
water is needed.
Vegetation nearby to provide shade for the
mosquito to hide during the day and digest the
blood meal from the night before.
MALARIA RISK FACTORS - 2
HUMAN
Poor water supply and sanitation.
 People nearby to provide reservoir of blood.
 People working in the fields and in irrigation
systems, near or on lakes and reservoirs etc.
 Migrants moving into malarial areas clearing land, looking for work, refugees etc.
 People (and mosquitoes!) travelling abroad,
especially by air; airport malaria.

Ideal breeding grounds for mosquitoes – still, shallow water.
Mosquito larvae at the edge of a pool.
Mosquitoes will breed in small puddles, even in animal
hoof prints, empty cans and bomb craters.
A high risk area – people, vegetation cover
and standing water during the wet season.
Collecting water,
an essential fact of
life for millions of
people, poses real
risks of being
bitten. However,
you cannot catch
the disease by
drinking water
containing larvae.
Poor housing, like this shanty, offers little protection.
4. THE SOLUTIONS
3 Areas of Control
 Against
the adult mosquito;
 Against
the eggs and larvae;
 Against
the Plasmodium, by treating
victims.
1. AGAINST ADULT MOSQUITOES
INSECTICIDE
SPRAYS
(SUCCESSFUL…BUT)
INSECTICIDE
TREATED BED
NETS
GENETIC
ENGINEERING
(VERY LIMITED SUCCESS)
(VERY SUCCESSFUL)
DDT
MALATHION
STERILE
MALES
KILLER
MALES
Insecticide sprays
are very efficient,
but there are
several drawbacks:
1. They are relatively
expensive, often
beyond the means
of poor villages;
2. Sprays must be
applied repeatedly
for long-term
effectiveness.;
3. They may
contaminate water
and crops.
4. Most importantly, mosquitoes
can quickly develop immunity
to the spray.
The effect of stopping the use of DDT in Sri Lanka (Ceylon). Was
the banning of DDT one of the costliest mistakes of all time? One
estimate suggests that 50 million children have died of malaria
since the use of DDT was greatly reduced in the 1960s.
A simple mosquito net may mean the
difference between life and death…
…even better if they are
dipped in insecticide, as in
this Kenyan village. The
normal chemical used for
ITNs (Insecticide Treated
Nets) is Permethrin, which
is harmless to humans,
but deadly to mosquitoes.
Several African countries
are trying to get more
people to use these nets,
by removing tax on them,
reducing their cost.
2. AGAINST EGGS AND LARVAE
PHYSICAL
CHEMICAL
DRAINING
BREEDING
SITES
SPRAYING
WITH
LARVICIDES
BIOLOGICAL
ADDING OIL, EGG
WHITES OR
MUSTARD SEEDS
FLUSHING
BREEDING
SITES
ADDING FISH TO
PONDS AND PADI
FIELDS
PLANTING
EUCALYPTUS
TREES
ADDING Bti
IN
COCONUTS
PHYSICAL CONTROL
Draining
Flushingbreeding
out breeding
places:
sites
because
by weekly
mosquitoes
releaseneed
of
Planting
Eucalyptus
trees
to
absorb
excess
water
water
so
little
canwater
drown
inthe
which
larvae,
to lay
but
their
can eggs,
only
be
it can
done
bein
fromareas
the
soil
breeding
sites.
suitable
virtually
impossible
andhelps
where
to drain
find
there
and
isdrain
surplus
them
water.
all.
BIOLOGICAL CONTROL
Adding larvae-eating fish, such as the Muddy Loach,
to padi fields and pools, can clear them of larvae
within a day.
BIOLOGICAL CONTROL - Bti
The bacillus Bti (Bacillus Thuringiensis Israelensis !!!) can be
incubated in coconuts, where it multiplies. The coconuts are
then broken open and thrown into pools, where the bacilli are
eaten by the mosquito larvae. They kill the larvae by destroying
its gut.
The incubation
stage
Adding
to pools
Spraying Bti
from a boat
BIOLOGICAL CONTROL - Bti
You can even
buy Bti over
the counter
in the U.S.
3. AGAINST THE PLASMODIUM…
An ingredient of Tonic Water (check in the
supermarket), Quinine was often taken with Gin
to mask its bitter taste. However, you would need
to drink about 25 Gin and Tonics a day to get the
1. Quinine: Originally
recommended dose.
extracted from the
bark of the South
American Cinchona
(Fever Tree), it was
for a long time the
main anti malarial
drug, but the
parasite has become
largely immune.
AGAINST THE PLASMODIUM…
2. Chloroquine: Became the
most common anti
malarial drug, but, like
Quinine, becoming
ineffective as the
Plasmodium mutates and
becomes immune to it.
..AGAINST THE PLASMODIUM
3. Artemisia (Wormwood):
Used as an anti malarial
herbal remedy by the
Chinese for hundreds of
years (known there as
Qinghaoshu), it was
“rediscovered” during the
Vietnam war and may
prove to be a major weapon
in the fight against malaria,
as plasmodium do not seem
to become immune to it.
VACCINATION
At the moment, there is no effective vaccine against
malaria, although scientists all over the world are
trying to develop one.
The search goes
on to try to find a
vaccine: the Bill
Gates Foundation
recently donated
more than $168
million towards
malaria research,
most of that to
find an effective
vaccine available
to all.
ROLL BACK MALARIA
Started in 1998, Roll Back Malaria is a global
programme aimed at halving the world's malaria
problem. It is a coordinated attempt involving the
WHO, UNICEF, the World Bank and many
governments and scientific and medical experts
across the world.
SUCCESS OR FAILURE?
At the moment there is no doubt that the
battle against malaria is being lost.
 This is mainly due to the ability of
mosquitoes to develop immunity to
pesticide sprays…
 …and to the Plasmodium’s ability to
develop resistance to drugs.

5. KEY REVISION POINTS
(i) – THE PROBLEM
Anopheles Mosquito;
 Plasmodium (e.g. Plasmodium Falciparum);
 Humid climate; 16-40ºC, abundant rainfall;
 Vegetation for shade;
 Areas of still or stagnant water;
 Humans to act as blood reservoir.
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5. KEY REVISION POINTS
(ii) THE EFFECTS
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1-3 million deaths each year, mostly children;
Lost education through bouts of illness;
Lost productivity by adults, especially at planting
and harvest time – less food, lower income;
Huge amount spent on trying to prevent or control
malaria - $2 Billion in Africa each year, maybe $100
Billion damage to Africa’s GDP; up to 25% of
family income; huge burden on health services;
Negative impact on foreign investment and tourism.
5. KEY REVISION POINTS
(iii) – THE SOLUTIONS
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DDT, Malathion;
Genetic engineering – sterile male mosquitoes;
ITNs – Insecticide Treated Bed nets;
Draining and flushing breeding sites;
Larvicide sprays to kill larvae;
Oil, egg whites and mustard seeds;
Bti, Fish (Muddy Loach), Eucalyptus trees;
Quinine, Chloroquine, Artemisia;
No effective vaccines yet - several on trial;
World Health Organisation campaign – Roll Back
Malaria.
Exam Advice
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Practice this topic using past papers – the questions
don’t vary that much from year to year.
Concentrate more on the Risk Factors, Costs and
the Solutions, less on the cycle of infection and
medical symptoms of the disease.
You must be able to comment on the effectiveness of
your chosen solutions, but don’t just say “very
effective” for them all and hope to get marks – the
markers will be looking for detailed knowledge of
the effectiveness of each solution you quote.
Try to learn a few (four or five) solutions in detail
and be able to quote names of pesticides, drugs, etc.
Presentation produced by Robbie Livingstone, Geography
Department, Dunoon Grammar School.
Photographs and diagrams are used without their authors’
permission and should not be used for any commercial
purposes.
Any constructive criticisms are welcome – to
[email protected]
…this presentation will have taken about half an hour to view.
In that time about 60 people, most of them babies and young
children will have died from malaria…