7 important things to know about mosquitoes

7 things worth knowing about mosquitos

Leo Braack, University of Pretoria
12:10 05/11/2015

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.
– Health24

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