Ugandan scientists to make a safe breed of mosquitoes

By Kikonyogo Ngatya SCIENTISTS at the Uganda Virus Research Institute (UVRI) are planning to produce a new breed of mosquitoes that does not spread malaria. The ‘super mosquito’ breed to be developed through the use of genetic engineering, would systematically displace the existing mosquitoes that transmit malaria parasites to human beings. Scientists say they now know the gene that makes mosquitoes interested in biting human beings. Their plot is to remove that gene and replace it with another one that causes the mosquitoes to bite rats and other small animals instead. Dr Louis Mukwaya, a mosquito expert at the institute says this kind of genetic manipulation would save millions of people world wide from malaria. “ The feeding or biting behaviour of mosquitoes is genetically determined. If you play around with those genes, their desire to bite humans can be changed,” he says. Another strategy being explored by UVRI scientists is to produce a breed of mosquitoes that can bite human beings but cannot spread malaria. Each time they suck the blood from an infected person, the malaria parasites die before the mosquito bites another person. “Normally, all the malaria causing parasites have to first develop inside the stomach of a mosquito before they can infect someone. They are then introduced into our bodies through the biting, “he said. Mukwaya says, “What is left is to take the mosquitoes into the environment. We have succeeded in making the malaria vectors not susceptible to malaria parasites. The parasites will not be able to grow inside their stomach. This process is what we call the refractory process,” he said. The third strategy would be aimed at reducing the mosquito population. The scientists plan to capture male mosquitoes from the wild and make them sterile. The sterile mosquitoes would be released back to the environment so that they can mate with the females in the wild, but can not fertilise the eggs. This means the eggs will not hatch into other mosquitoes, and therefore their population reduces. The sterile males would aggressively out compete the natural males in the wild. “We also plan to introduce a gene which when one male mosquito mates with a female, the second male to mate with that particular female will pick the sterile gene. This would also make it sterile,” he said. “We have a variety of control measures to choose from when making the ‘super mosquito’. However we are likely to first use the technique of making them kill the malaria parasites in their stomachs.” In Uganda, malaria is the leading cause of sickness and death. Prof. Francis Omaswa, the Director General for Health Services said Uganda has been chosen by international bodies to undertake a multi- million -dollar research project on genetically modified mosquitoes. ends