Plagues, Pestilences and Diseases
Notorious malaria mosquito strains evolving
New research finds two malaria mosquito strains could become immune to
effects to control them
* Press Association
*
guardian.co.uk, Thursday 21 October 2010 20.59 BST
female mosquito Anopheles malaria Two new resistant strains of Africa's
anopheles malaria mosquito have been discovered. Photograph: Alamy
Two strains of Africa's most notorious malaria mosquito are evolving
into new species, research has shown.
The discovery has implications for combating malaria, since it means
the insects could become immune to control strategies.
Scientists studying the mosquito anopheles gambiae, which is chiefly
responsible for spreading malaria in sub-Saharan Africa, found two
strains were rapidly diverging in their genetic make-up, despite
appearing physically identical.
Dr Maria Lawniczak, a member of the team from Imperial College London,
said: "From our new studies, we can see that mosquitoes are evolving
more quickly than we thought and that unfortunately, strategies that
might work against one strain of mosquito might not be effective
against another. It's important to identify and monitor these hidden
genetic changes in mosquitoes if we are to succeed in bringing malaria
under control by targeting mosquitoes." Genetic differences between the
two strains, known as M and S, were scattered throughout the insects'
DNA, said the researchers, writing in the journal Science.
The changes had occurred in areas likely to affect development, feeding
behaviour, and reproduction.
A further study comparing the two strains showed they seemed to be
evolving differently.
This was thought to be in response to different environmental factors
such as larval habitats, infectious agents and predators.
Co-author Professor George Christophides, also from Imperial College,
said: "Malaria is a deadly disease that affects millions of people
across the world and amongst children in Africa, it causes one in every
five deaths. We know that the best way to reduce the number of people
who contract malaria is to control the mosquitoes that carry the
disease. Our studies help us to understand the makeup of the mosquitoes
that transmit malaria, so that we can find new ways of preventing them
from infecting people."