1. Not all mosquitoes bite.
The female
mosquitoes are the dangerous ones. They bite and draw blood. Male
mosquitoes feed on flower nectar. Males have very hairy and fuzzy
antennae (like a powder puff) whereas females have less hairy antennae.
2. There are three types of malaria carrying mosquitoes.
The
top three malaria transmitters in Africa are Anopheles gambiae,
Anopheles funestus and Anopheles arabiensis. The first two live in areas
of Africa where there is higher rainfall while the third, Anopheles
arabiensis, is a more savanna-based, arid zone species.
Gambiae
and funestus prefer to feed indoors and are strongly attracted to
humans, but arabiensis feeds as easily outdoors as indoors and also as
easily on cattle and other animals as humans. This means it is easier to
target gambiae and funestus using indoor methods such as spraying walls
with insecticides and using insecticide-impregnated bed nets. The
outdoor-feeding arabiensis is far more difficult to control.
In
most areas all three species have a peak of biting in the early hours of
the morning when people are in their deepest sleep and less likely to
disturb mosquitoes during the feeding process. There are also other
important species of malaria-transmitting mosquitoes but they are more
localised in distribution.
3. Mosquitoes have started to change their feeding patterns.
Because
of the strong focus on indoor strategies to fight malaria transmitting
mosquitoes using bed nets and indoor spraying, genetic selection is
resulting in some populations of these mosquitoes biting outdoors and
earlier at night when people are not protected by bed nets. It means
these mosquitoes are more difficult to reach with insecticides, just as
is the case with Anopheles arabiensis.
4. Most mosquito
bites are harmless. It’s only the ones that carry certain types of
parasites that lead to malaria, and potentially death.
In
Africa, there are four known species of microscopically small parasites
that can cause the disease we call malaria. All four belong to the
group Plasmodium. The most common of these parasites in Africa is Plasmodium falciparum, which is the most deadly of the four species.
Birds and some other groups of animals carry their own species of Plasmodium,
which is also transmitted by mosquitoes, but they do not cause malaria
in humans. Mosquitoes also carry many other disease-causing organisms
such as yellow fever virus, West Nile virus, Rift Valley fever, and the
worms that cause the dreaded disfiguring elephantiasis (filariasis).
5.
Mosquitoes select where they feed on the body. They have very acute
sensory mechanisms (like heat-seeking missiles) that lead them to select
particular parts of the body (such as ankles) to feed from.
All
three of the main malaria carrying mosquitoes have similar biting
preferences. If you are sitting or standing outside in the evening the
overwhelming majority will try to feed on your ankles and feet - so make
sure you cover these areas with repellent or wear socks and shoes.
The
antennae of mosquitoes are highly specialised sensory organs that can
detect very small amounts of chemical cues that lead them to food and
mates. Various chemicals, of which carbon dioxide is one, help female
mosquitoes track down their hosts. Pheromones, which are hormones
secreted as odours into the environment, enable males and females to
meet and mate. They are also detected by the antennae.
6. Malaria mosquitoes do not like wind.
Using
a fan over you when going to bed will lessen your chances of being
bitten. These mosquitoes don’t like flying when there is even a slight
breeze.
7. 97 countries and territories still face ongoing malaria transmission.
According
to the World Health Organisation, an estimated 3.2 billion people, or
just under half the world’s population, are at risk of getting malaria.
The bulk of the malaria burden is shouldered by Africa where 89% of
cases and 91% of deaths occur.
This article was originally published on The Conversation. Read the original article.
7 things worth knowing about mosquitos
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Oleh
healthandwealth
