It′s two steps forward and one step back in the fight against malaria | Science| In-depth reporting on science and technology | DW | 24.11.2015
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It's two steps forward and one step back in the fight against malaria

Malaria research advances yet again! This week alone we've had two separate research groups - one in Germany and one in the US - announce new findings. But there's still no vaccine in sight.

Biologists at the University of California have created a strain of mosquito with a malaria-blocking gene. And other scientists at Heidelberg University Hospital have managed to remove part of the malaria genome so that the genetically modified parasite is unable to develop in the host.

The question is whether these two advances in research mean it's the end of the deadly tropical disease?

And the answer is "not quite."

Genetically modified mosquitoes

The idea behind the Californian research is simple. Mosquitoes carrying a malaria-blocking gene could safely pair with "normal" Anopheles mosquitoes in the wild, because in theory their offspring would be unable to transmit the disease.

Ideally, the malaria-blocking gene would spread swiftly through mosquito populations.

"It can spread through a population with great efficiency, increasing from 1 percent to more than 99 percent in 10 generations, or about one season for mosquitoes," University of California-San Diego biologist, Valentino Gantz, told the Reuters news agency.

The researchers inserted extra DNA into the cells of the Anopheles mosquito. The DNA will be passed on through generations of the species, with the hope it will create mosquitoes carrying the malaria-blocking gene.

But these genetically modified mosquitoes have yet to be released and tested in the wild.

And they will not bring us victory over the deadly disease single handedly.

"We do not propose that this strategy alone will eradicate malaria," University of California-Irvine molecular biologist, Anthony James, told Reuters.


Manipulating malaria: could genetically modifying mosquitoes end the deadly disease?

But James said it could play a major role in eliminating malaria if used in conjunction with treatment and preventive drugs, future vaccines, and further education of communities in the most affected regions.

This includes making sure people use bed nets and eradicate mosquito-breeding sites.

Amputated parasite

At the Heidelberg University Hospital, meanwhile, scientists took a slightly different approach. Rather than modify the mosquito, they opted to modify the parasite.

The researchers at the Center for Infectiology created a parasite which sheds more than 200 of its own genes. It carves up its genome and in the process loses half of an important chromosome, which it needs for its further development.

They hope to use this research as the basis of a future vaccine - because when patients are given a vaccine they are injected with parasites which enter the liver and either die or cease to develop there. The immune system then uses these harmless parasites to establish a line of defense.

Malaria researcher Mirko Singer

Singer: it's early days

Mirko Singer, a Ph.D. student at the Center for Infectiology, says his team is testing the modified parasite on mice.

"At the moment it's just an experimental vaccine," Singer told DW. "If we were to produce a safe vaccine, we would have to ensure the parasite was unable to develop further on a number of different levels."

Unexpected setback

And safety is a keyword. In some mice, the modified parasite did continue to develop.

Singer says the problem was a repair mechanism, which is rare in humans, but which took affect in some the parasites and restored the "amputated" genome.

So there is work for the researchers yet.

It remains unclear whether or when any of this research will lead to a malaria vaccine.

"I couldn't comment at all on that," says Singer. "People have often made incorrect predictions about how quickly we can move such studies into the real world."

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