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Millions of People Worldwide Die from
Malaria
Every year, millions of people worldwide die from malaria, mostly in
sub-Saharan Africa. A programme that seeks to hand out millions of bed
mosquito nets is going on in developing countries. Villages across the
countries have been doused with insecticide. But those measures have not
put a significant dent in malaria cases. After a string of failed
initiatives, the United Nations recently announced a campaign to provide
bed nets to anyone who needs them by 2010. How well they succeed with
these remains to be seen. Either the bed nets have been destroyed by poor
handling or by pests like mice or have quickly been exchanged through the
local traders with cheap foods which is more of an immediate need to the
target groups.
Some scientists think creating mutant mosquitoes resistant to the disease
might work better. Yeya Toure, a tropical disease expert at the World
Health Organization has said the world has a malaria burden that is ever
increasing every year. Under such circumstances, they have to investigate
whether genetically modified mosquitoes could make a difference.
Genetically Modified Mosquitoes so Promising
The Bill & Melinda Gates Foundation has found the work on genetically
modified mosquitoes so promising it has invested nearly $40 million into
genetic strategies to stop mosquitoes from transmitting diseases like
malaria and dengue fever. The Bill & Melinda Gates Foundation believes
this is one of those high-tech, high risk innovations that would
fundamentally change the struggle between humans and mosquitoes. Dr.
Regina Rabinovich, director of infectious diseases development at the
Gates Foundation agrees that mosquitoes bred to be immune to malaria could
break the disease's transmission cycle. "That is the nirvana of malaria
control," said Rabinovich. "It would potentially transform what the field
looks like."
Crisanti has already proved that it is possible to create a genetically
modified mosquito by inserting a gene that glowed fluorescent green in
males. Among other possibilities, he and his team are now planning to
create sterile male mosquitoes to mate with wild female mosquitoes, thus
stunting population growth. They are also trying to engineer a
malaria-resistant mosquito. And in 2007, American researchers created
mosquitoes resistant to malaria that infects mice. Other scientists are
active in altering the DNA of the mosquitoes that spread dengue.
Too Many Genetic Puzzles Need be Solved
But not all scientists think these super mosquitoes are such a good idea.
Some think there are too many genetic puzzles to be solved for modified
mosquitoes to work. For example: the malaria-causing parasite, which
mosquitoes then transmit to humans, is simply too good at evading anything
scientists might devise to protect the mosquito. Whenever mosquitoes have
developed genes resistant to the malaria-causing parasite, the parasite
has always found a way around it.
For this to work, scientists will have to genetically modify billions of
these mosquitoes. And as it is usually the case, some environmentalists
are worried that genetically modified mosquitoes might wreak havoc in the
ecosystem. "Can't we just give mosquito nets to people instead of looking
at these really complex technological fixes that mess with the very
delicate balance of nature and evolutionary history?" asked Gillian
Madill, a genetic technologies campaigner at Friends of the Earth in
Washington.
Do not Fool with Mother Nature
But Dr. Rabinovich of the Bill & Melinda Gates Foundation knows very well
that rigorous testing would have to be done before releasing any
genetically modified mosquitoes into the wild. It is true it is not good
to fool with Mother Nature but if one can come up with another way of
tackling malaria that is workable and far better than giving free bed nets
to hungry population, then the world will listen to him.
Over the next year, the world will look forward to see Crisanti finalize
plans for a test release of genetically modified mosquitoes in southern
Italy. There, millions of the insects will be set loose in large cages to
determine things like how they might interact with wild mosquitoes and how
many would be needed to knock out malaria. Crisanti acknowledged there
might be unintended consequences of releasing genetically modified
mosquitoes into the wild, although he could not predict what they might
be. He, like many others, believes it is a risk worth taking. There is a
moral good to doing it. If Crisanti and his team can do this right, the
mosquitoes will get rid of malaria for us.
Unless one is in support of using malaria to control breeding of people,
then Crisanti’s genetically modified mosquitoes should be given a chance.
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A Mosquito Egg can Remain Dormant for
Several Years
1. A mosquito egg can remain dormant for
several years in absence of water. Rift valley fever is generally observed
during years in which unusually heavy rainfall and localized flooding
occur. The excessive rainfall allows mosquito eggs to hatch. The mosquito
eggs are naturally infected with the rift valley fever virus. Once they
hatch, the mosquitoes transfer the rift valley fever virus to the
livestock on which they feed. Once the livestock is infected, other
species of mosquitoes becomes infected from the animals and will spread
the disease to other animal and human.
2. Mosquitoes have been around for 100 million years. In that time they
have diversified into more than 3,000. They have successfully adapted to
climates from the arctic to the equator and developed means of locating
indigenous blood hosts in each locale.
3. Mosquito-borne diseases like malaria, yellow fever, dengue fever kill
more people than any other disease. The female mosquito requires a blood
meal for development of her eggs. Mosquito adults feed on flower nectar,
juices, and decaying matter for flight energy. The larval and papal stages
can be found in a variety of aquatic habitats.
4. The average life span of a female mosquito is 3 to 100 days. The male
lives 10 to 20 days. One female mosquito may lay 100 to 300 eggs at a time
and may average 1,000 to 3,000 off springs during her life span.
Mosquitoes breed in standing water. Rain gutters, tree holes, old can with
stagnant water are good breeding sites. A mosquito develops from egg to
adulthood in 4 to 7 days. Most mosquitoes remain within a 1 mile radius of
their breeding site.
5. Mosquitoes can't see you until they are 10 meters away. When they are
about 4 meters away they use extremely sensitive thermal receptors on the
tip of their antennae to locate blood near the surface of the skin. The
range of these receptors increases threefold when the humidity is high.
Mosquitoes locate blood hosts by scent, sight and heat. From 30 meters
mosquitoes can smell your scent, especially the carbon dioxide you exhale.
Mosquitoes respond to higher-than-normal concentrations of carbon dioxide,
especially when the carbon dioxide is mixed with host-odor. They follow
your scent upwind, and can see you at a distance of about 10 meters.
6. Aedes Aegypti mosquito originated in Africa and spread throughout the
tropics. It carries disease and is a major pest because it seems to prefer
omnivorous blood hosts such as monkeys, apes and people. This mosquito is
not afraid to make its home indoors.
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