Discovery of how malaria-bearing mosquitos sniff-out humans
Updated
Scientists say they have discovered that the mosquito which transmits malaria has a second set of odour sensors that sense humans.
Researchers from the US say the extra set of olfactory sensors are fundamentally different from the set of sensors that has been studied up until now.
The research provides the building blocks for developing more accurate repellants to help reduce the spread of killer mosquito borne diseases.
Presenter: Bronwyn Herbert
Speaker: Nigel Beebe, University of Queensland
- Listen:
- Windows Media
BRONWYN HERBERT: A single bite by the anopheles gambiae is enough to kill. This species of mosquito is responsible for spreading malaria, a disease which infects 250 million people a year and kills 900,000. Now scientists from the Vanderbilt University in Tennessee have found these insects have a second set of smelling sensors.
As Nigel Beebe from the University of Queensland explains.
NIGEL BEEBE: They're using the genome that sequenced in 2002, they've mined into the genome, they've found the repertoire of genes that are associated with olfactional smell. And in the process of doing that they stumble across another pathway in which the mosquito smells and this is a completely novel pathway to how we understand the process of olfactional or smell.
BRONWYN HERBERT: Dr Beebe, who specialises in mosquito molecular biology, says identifying this new pathway is a significant breakthrough.
NIGEL BEEBE: Initially there were some hypotheses that the repellent that repelled the mosquitoes, based on a chemical called DEET, I think it was developed by the American army in the ‘40s had this fantastic repulsion activity with mosquitoes and we always thought that what it was doing was jamming the antennae of the mosquito, or preventing the mosquito from being able to smell.
But we actually find out now that this repellent is actually being smelt by the mosquito, there are receptors that actually pick up these molecules and they process it in the brain of the mosquito and the answer to that molecule is, 'Yuck, I don't like it I've got to get away from here. So probably something similar to, you know, if you were smelling a dog poo and you would want to get away from it.
BRONWYN HERBERT: So what are the practical implications of knowing this?
NIGEL BEEBE: Well, that is a molecule that repels mosquitoes okay, and the development of better repellents would be a great thing for the world of malaria, especially repellents that were long lasting and very non-toxic.
BRONWYN HERBERT: And not just repellents, but lures as well.
NIGEL BEEBE: So using what we understand about how the mosquitoes smells humans and being able to play with that in some way we might be able to develop much better attractants to actually have the mosquitoes not come into village houses, but be attracted to traps that would just hold them or kill them.
BRONWYN HERBERT: Dr Beebe says the research also contributes to a better understanding of the biology of olfaction or an ability to sense your environment through smell. The research is published in the Public Library of Science Biology Journal.
