Mosquitoes Suck
As I’m sure some of you are aware, the mosquito has caused more
deaths than all other insects combined. There are over 3,500 species of
mosquito only about 4 of which carry major diseases. These diseases are
normally carried by parasites that live in the mouthparts of the mosquito and
reproduce inside it, until they are transferred to a human host when the
mosquito bites them.
In addition, only adult female mosquitoes bite, since they
need lipids and proteins in their diet in order to produce eggs for
reproduction; the male mosquitoes are content to consume solely nectar. When a
female mosquito bites, it pierces the skin with a proboscis and searches for a
capillary. When one is found, the mosquito releases its saliva which acts as an
anti-coagulant to ensure that your blood does not clot, so that she can consume
as much as she is able. Your immune system sends histamine when the saliva is
detected and this causes your blood vessels to swell in a mild allergenic
response; you receive the parting gift of a small red itchy bump, and she
leaves with your blood, which will help her to produce some of the 500 eggs that
she will lay in her lifetime (around 6-8 weeks if conditions are favourable).
The main issue with mosquitoes is their aforementioned capability
to carry diseases, which affect hundreds of millions of people each year, malaria
being the main culprit. 200 million people a year are impacted and 1 million of
those will die; over a quarter of the deaths caused by malaria are the result of
the use of fake medicines.
Another disease that is spreading rapidly is the Dengue
Virus which has likely origins in the Swahili phrase “Ka-Dinga Pepo” meaning “sudden
cramp-like seizures originating from an evil spirit”. The disease spreads
rapidly due to the species that carries it – the Aedes Aegypti – which actually
prefers the taste of human blood than that of animals and so lives in urban
areas. Although they only travel around 200 yards in their lifetime, these
mosquitoes lay their eggs in water like any other species, and then we
transport the mosquitoes around the world ourselves, inadvertently helping with
the spread of the disease. There are an estimated 50 – 100 million cases of
Dengue virus a year, with Brazil spending $1 billion just to control it.
Unfortunately, mosquito activity coincides with human activity, so there is no
scarcity of blood for this vector.
There are four strands of the virus, and although you would
develop immunity to the strand that afflicts you, you actually become more
susceptible to the other strands as a result, so if you were to become infected
by a new strand, the consequences are much more severe and you are more likely
to die as a result.
Oxitec, a company helping to fight this disease, have
genetically modified male mosquitoes so that they carry a self-limiting gene
that causes the deaths of offspring before functional adulthood is reached.
When released into villages in which the virus was spreading, there was a drop
of 50% - 90% of cases of Dengue fever.
This suggests hope for a vector free future that isn’t all
too far away.
I hope you found this informative and interesting.
By Louis Lane.
Sources:
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