Can genetically modified animals control the spread of disease?

Scientists have a new weapon against dengue fever. You may have heard about the new method already:the researchers released sterile males into the wild in Malaysia.

In December, scientists set free 6,000 genetically modified mosquitoes into the forests of Malaysia to see how they would mate with the female mosquitoes. In theory, the less mosquitoes there are, the less cases of dengue fever there will be.

Female mosquitoes are the only ones that can transmit diseases though their infectious bite.

Technically, a wild female who has sex with a sterile male, will have no offspring at all or will have offspring that don't make it to adulthood.

Scientists are hoping that genetically modified mosquitoes will act as sort of a new kind of birth control to reduce mosquito numbers by limiting the spread of dengue.

The Malaysian trial may be the first real world that demonstrate GM mosquitoes can be used to fight off dengue fever, an infection that can lead to a fever with headaches, muscle and joint pain - and sometimes death.

There were 134 fatal cases of "break-bone" fever in Malaysia last year. But the disease affects up to a hundred million people around the world. The mosquitoes prefer warm, wet places in urban or semi-urban environments. As many as 2.5 billion people live in regions where the mosquito-borne illness is considered endemic, reports Time.

The Malaysian Institute for Medical Research spearheaded the trial, which began mid-December and ended shortly after that in the beginning of January. It will be interesting to see how the 6,000 GM male mosquitoes did. Just how did they do compared to a control population of non-GM males, that is.

But environmentalists are a little worried about what's going to happen when these GM mosquitoes mate in the wild and spread their genes.

According to Fast Company:

"I am surprised that they did this without prior announcement given the high level of concerns raised not just from the NGOs but also scientists and the local residents," said Third World Network researcher, Lim Li Ching. "We don't agree with this trial that has been conducted in such an untransparent way. There are many questions and not enough research has been done on the full consequences of this experiment."

Should we be worried about this? The authorities don't think so. The GM mosquitoes were only designed to live for a couple of days.

The GM mosquito sex experiment has already worked in the Cayman Islands.

Oxitec’s Chief Scientific Officer, Luke Alphey, said in a statement: “The results from the Cayman trial show that our method works in principle, but with such a small area involved, it would have been difficult to detect a drop in dengue cases. Our estimates suggest that an 80 per cent reduction in mosquitoes should result in fewer dengue infections and we are hopeful that these effects will begin to be seen in the larger Malaysian trial.”

GM mosquitoes kind of act like an insecticide minus the nasty chemicals. And the scientists insist releasing sterile males into the environment won’t have lasting effects because the gene won’t be passed on from generation to generation.

Simon Hales, a researcher at the University of Otago, previously told Time:

"But those who would suggest that it has nothing to do with it are equally misguided." Hales estimates that if global warming advances as predicted by the U.N., more than half the world could be dengue country before the end of this century.

Other researchers are betting on the GM mosquito technique to fight off other diseases caused by these blood sucking creatures.

For instance, University of Arizona entomologist Michael Riehle is working on GM mosquitoes designed to eliminate malaria.

“Insecticide-treated bed nets, or drugs to cure the malaria are effective ways [to prevent malaria], except resistance is developing against the parasites,” Riehle previously told me.

Give the genetically engineered mosquitoes 10 years to emerge as a viable solution to the fight against malaria. However, this will only happen if the mosquitoes can compete with the disease-ridden wild ones.

Again, not everyone is convinced that releasing GM mosquitoes is...completely harmless.

According to Popular Science:

Jo Lines, a malaria expert at the London School of Hygiene and Tropical Medicine has described the process as “a series of arms races that the [malaria] parasite has consistently won.” Three percent of the offspring from Oxitec’s tetracycline-dependent mosquitoes survive—what happens if those bugs breed with wild mosquitoes?

It’s even possible that the changes we induce in mosquitoes could move into other animals..

Malaysia Releases 6,000 Genetically Modified Mosquitoes into the Wild [Popular Science]

Related on SmartPlanet:

• Mosquito trial set to reduce dengue infection in Malaysia
• How engineering malaria-resistant mosquitoes could save millions of lives
• New on the menu: GM salmon
• Monsanto: Supreme Court lifts ban on genetically modified seeds
• How modified genes can make their way into the wild

This post was originally published on Smartplanet.com