GM mosquitoes may not spread malaria
Genetically-modified mosquitoes that are resistant to a malaria parasite may one day stop the spread of the disease, a new US study says.
In research published online in the Proceedings of the National Academy of Sciences, scientists describe how the genetically-modified, or GM, mosquitoes outbred natural mosquitoes when fed mouse blood infected with a malaria parasite.
The research may offer a way of controlling malaria by introducing the genetically altered insects into the wild and having them take over from their natural cousins.
The scientists at Johns Hopkins University combined equal numbers of genetically modified and natural mosquitoes in the laboratory and let them feed on malaria-infected mice.
The genetically-altered insects survived in greater numbers and laid more eggs.
After nine generations, 70% of the mosquitoes were GM ones compared with 50% at the outset of the experiment, Professor Marcelo Jacobs-Lorena and his colleagues write.
The study suggests that when feeding on malaria-infected blood, "transgenic malaria-resistant mosquitoes have a selective advantage over non-transgenic mosquitoes", the authors write.
The lab-altered mosquitoes competed equally well with natural insects when fed non-infected blood but did not outbreed their natural counterparts in that case, according to the study.
For the strategy against malaria to be effective, transgenic mosquitoes would have to outbreed the natural insects when feeding off untainted blood.
Further research is still needed before the altered insects could be released into the wild, as only a small percentage of mosquitoes in nature are exposed to malaria, the authors write.
Still, the research carried "important implications for implementation of malaria control by means of genetic modification of mosquitoes", the authors write.
The experiment used the malaria parasite Plasmodium berghei and not the more dangerous parasite P. falciparum, the deadliest of the four parasites that cause malaria in humans.
US researchers announced in December that they had developed an experimental vaccine that would neutralise the malaria parasite inside its mosquito host.
The vaccine targets the P. falciparum parasite inside the gut of the mosquito, blocking the organism's development and preventing further transmission of the disease.