Malaria parasite lures mosquito to human odour
UK: Mosquitoes carrying the malaria parasite are more
attracted to human body odour than uninfected insects, a study suggests.
Researchers found that infected insects were three times more likely
to be lured towards a human scent. They believe that the deadly
parasites are seizing control of their biting hosts and boosting their
sense of smell.
The research is published in the journal Plos One.
Dr James Logan, from the London School of Hygiene and Tropical
Medicine (LSHTM), said: “One thing that always surprises me about
parasites is how clever they are. They are these ever-evolving organisms
that seem to be one step ahead of us the whole time.”
To carry out the study, the researchers infected malaria mosquitoes
(Anopheles gambiae) with the most deadly form of parasite, Plasmodium
falciparum. It is a very effective way of collecting body odour... the
odour can remain attractive for months,” explained Dr Logan.
The scientists repeated the experiment with uninfected insects.
They found that mosquitoes carrying the deadly parasite were three
times more likely to be attracted to the smelly stockings.
The scientists believe this is because the tiny parasitic organisms
are manipulating their hosts’ sense of smell.
Dr Logan said: “We think it is giving them a heightened sense of
smell. We are hypothesising there is an alteration somewhere in their
olfactory system that allows them to find us quicker.”
By making humans an easier target, the parasite is more likely to be
passed into the blood stream - ensuring its survival and continuing the
spread of the deadly disease.
He said: “If we know how the parasite is able to manipulate the
olfactory system... perhaps we can identify new attractants for infected
mosquitoes and we will be able to increase our efficiency with trapping
techniques.”
According to the latest figures, the World Health Organization said
there were about 219 million cases of malaria in 2010 and 660,000
deaths. Africa is the most affected continent: about 90% of all malaria
deaths occur there.
- BBC NEWS |