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Development & Health Malaria
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Page 1: Development and Health - Malaria

Development & Health

Malaria

Page 2: Development and Health - Malaria

The female Anopheles mosquito

Page 3: Development and Health - Malaria

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.

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Malaria distribution

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breedingMosquitoes breed

in any stagnant water

flooded rice fieldspuddlestin cans

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Ideal breeding grounds for mosquitoes – still,

shallow water.

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Mosquito larvae at the edge of a pool.

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Mosquitoes will breed in small puddles, even in animal hoof prints, empty cans

and bomb craters.

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A high risk area – people, vegetation cover and standing water during the wet season.

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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.

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Mosquito larvae hang from the surface tension of the water, breathing

through their siphon tube.

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Sampling larvaeScientists are

sampling larvae in order to target spraying

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A jar containing mosquito larvae.

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An adult emerges, the males to look for plant nectar, the females for blood.

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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.

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Posters are used to educate people about the disease and its symptoms

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3 Areas of Control

Against the adult mosquito;

Against the eggs and larvae;

Against the Plasmodium, by treating victims.

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1. AGAINST ADULT MOSQUITOES

INSECTICIDE TREATED BED

NETS(VERY SUCCESSFUL)

GENETIC ENGINEERING

(VERY LIMITED SUCCESS)

DDT

MALATHION

STERILE MALES

KILLER MALES

INSECTICIDE SPRAYS

(SUCCESSFUL…BUT)

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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.

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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.

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A simple mosquito net may mean the difference between life and death…

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…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.

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2. AGAINST EGGS AND LARVAE

PHYSICAL CHEMICAL BIOLOGICAL

DRAINING BREEDING

SITES

FLUSHING BREEDING

SITES

PLANTING EUCALYPTUS

TREES

SPRAYING WITH

LARVICIDES

ADDING OIL, EGG WHITES OR

MUSTARD SEEDS

ADDING FISH TO PONDS AND PADI

FIELDS

ADDING Bti IN

COCONUTS

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PHYSICAL CONTROL

Draining breeding places: because mosquitoes need so little water in which to lay their eggs, it can be virtually impossible to find and drain them all.

Flushing out breeding sites by weekly release of water can drown the larvae, but can only be done in suitable areas

and where there is surplus water.

Planting Eucalyptus trees to absorb excess water from the soil helps drain

breeding sites.

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BIOLOGICAL CONTROL

Adding larvae-eating fish, such as the Muddy Loach, to padi fields and pools, can clear them of larvae within a day.

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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.

Spraying Bti from a

boat

The incubation

stage

Adding to

pools

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BIOLOGICAL CONTROL - Bti

You can even buy Bti over

the counter in the U.S.

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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 recommended dose.

1. Quinine: Originally

extracted from the bark of the South American Cinchona (Fever

Tree), it was for a long time the

main anti malarial drug.

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AGAINST THE PLASMODIUM…

2. Chloroquine: Now the most common anti malarial drug, but, like Quinine, becoming ineffective as the Plasmodium mutates and becomes immune to it.

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..AGAINST THE PLASMODIUM3. 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.

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VACCINATION

At the moment, there is no effective vaccine against malaria, although

scientists all over the world are trying to develop one.

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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.

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Mosquitoes tend to be most active from dusk into the night. Spraying the shaded sides of trees and buildings during the day while they are resting is a common approach to eradication.

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Drug resistancePlasmodium

develops resistance to drugs

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Artemisinin combination therapy

Artemisinin is a new drug which is effective if used in combination with other drugs.It is believed that resistance is much less likely to develop againstA.C.T.

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The use of bed nets

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Bed net programme - Malawi

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Bed net treatment

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BackgroundThe 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.

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Malaria is a disease which is endemic in many countries – this

means it is always present.

It is predominantly a disease of the Tropics.

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…with global warming, however, malaria may be closer than you think…