Science News

Spermless mozzies could help fight Malaria

Wed, 10th Aug 2011

Emma Stoye

Releasing spermless male mosquitoes could help reduce outbreaks of malaria, according to a study published this week in the journal PNAS.

Malaria causes over a million deaths every year, 90% of which occur in Sub-Saharan Africa.  It is caused by the microscopic parasite Plasmodium, which is transmitted between human hosts by female Anopheles mosquitoes.  As there is no widely available vaccine, attempts to limit outbreaks in susceptible populations have focussed on controlling the numbers of mosquitoes using insecticides.  These strategies are becoming less successful as mosquitoes develop resistance to the chemicals used.

Researchers from Imperial College London have been investigating ways of reducing the numbers of malarial mosquitoes by hindering their reproduction.  Their work focussed on Anopheles gambiae, the most common vector species in Africa.  Females of this species mate only once in their lifetime, after which they lay a large number of eggs and are no longer receptive to maleAnopheles gambiae Mosquitos.

The researchers created sterile male mosquitoes that did not produce sperm by injecting individual embryos with fragments of RNA to silence the zpg gene involved in sperm development.  When mated to these spermless males, females showed the same post-mating behavioural responses as they did with fertile males.  Dr Flaminia Catteruccia from Imperial College London said “These females did not seem to realise they had not received sperm, so they behaved as normal.  They started laying [sterile] eggs and completely switched off their receptivity to further matings.”

The mass release of these spermless males could be a good way to control mosquito numbers, and thus reduce malaria transmission, in high-risk areas.  However, there is still much work to be done.  Dr Catteruccia said “Our method is not immediately transferable to the field because the way we target sperm is a laborious process: we have to inject every individual mosquito. In the future there may be more high-throughput techniques, but these have not yet been developed.”


Subscribe Free

Related Content


Make a comment

There have been a number of such wild solutions to malaria. Some scientists just love the idea of breeding mosquitoes to death. This has never worked and is not likely to work.

And there are obvious ways to reduce malaria exposure that are much cheaper: bed nets and social support that will allow people to, temporarily or permanently, change their behaviors so that they can avoid the particular mosquitoes. PhysBang, Thu, 11th Aug 2011

I wonder what would happen if they speciated mosquitos; release dozens and dozens of apparently compatible, but actually genetically-modified, incompatible males. That way you could breed them up in species batches and then just mix them up and release them.

The females would be unable to know them apart, so the population would take a huge nose dive; 90+% of matings leading to death would not be sustainable.

Eventually they would evolve some way to tell, like a pattern on them or a smell or something but it could take quite a while, and if that happened, you could capture them, and do it again. wolfekeeper, Thu, 11th Aug 2011

I recall this idea being bandied around several years ago.

The one big problem I have with all these remedies is that Man does not seem to be able to adapt to the new situation. Are we prepared for the 1m people who die annually from malaria to remain alive?

If malaria, and other such disease, can be eradicated, we MUST reeducate the people to have fewer children, or the world will be over run with hungry humans in no time at all. Don_1, Wed, 17th Aug 2011

See the whole discussion | Make a comment

Not working please enable javascript
Powered by UKfast
Genetics Society