by Playfuls Staff |
20th March 2007
Scientists have created a mosquito that could very well save thousands of lives: it is resistant to malaria.
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Researchers are excited and hopeful because they have succeeded to genetically engineer a mosquito that is resistant to malaria. Furthermore, the modified insect survives better than its disease-carrying ‘brethren’ and the gene is transmitted to future generations.
If such a mosquito can dominate in the wild, replacing the parasite-bearing ones, it could prevent humans being infected with malaria.
Researchers led by Marcelo Jacobs-Lorena at the Malaria Research Institute at Johns Hopkins University in Maryland created genetically modified mosquitoes by giving them a gene that made it impossible for them to pass on the plasmodium parasite that causes malaria.
Some 1,200 genetically modified mosquitoes were then released into a cage holding malaria-infected mice and the same number of wild mosquitoes. As they reproduced, more of the transgenic mosquitoes survived. After nine generations, 70% of the insects belonged to the malaria-resistant strain.
The ones immune to the parasite lived longer and laid more eggs.
The scientists wrote in the journal Proceedings of the National Academy of Sciences: “To our knowledge, no-one has previously reported a demonstration that transgenic mosquitoes can exhibit a fitness advantage over non-transgenics.”
“This fitness advantage has important implications for devising malaria control strategies,” they write.
This new method of eradicating malaria, made with cheap laboratory techniques, could be more feasible than the chemical sprays and other treatments used now.
According to scientists, trials in sub-Saharan Africa could be conducted within five years, but first they will have to prove as far as possible that the resistance genes will not trigger a more aggressive form of malaria, or spread to other insects.
Scientists are focusing on ways to perfect how resistance genes are inherited, ensuring they are passed on in every mosquito egg. Normally, offspring have a 50% chance of inheriting a specific gene from the mother (in wild populations, it is the females that carry the malaria parasite, but only a small fraction of them).
Malaria is spread by the single-celled parasite Plasmodium and is endemic in parts of Asia, Africa, and central and south America. The organism is passed to humans through the bite of the Anopheles mosquito. Some 300 million people become ill annually, 1 million losing their lives to it around the world.
Approximately 90% of cases are in sub-Saharan Africa, where a child dies of malaria every 30 seconds.
Ever hopeful, the researchers say: “The results have important implications for implementation of malaria control by means of genetic modification of mosquitoes.”
