Malaria, Zika, dengue fever could be wiped out with sterile mosquitoes

Scientists genetically modify female bugs to be unable to lay eggs, bite people, suck blood
Scientists have found a way to genetically modify mosquitoes, which could help eradicate diseases such as malaria.

Experts at a top-secret laboratory in Terni, Italy, believe that mutating the female insects’ Deoxy ribonucleic Acid (DNA)/genetic material to make them more male – what they call ‘a kind of hermaphrodite’ – is the answer.

This is because only females have mouths big enough to bite human beings, which continues the spread of infections including Zika and dengue fever.

Thus, diluting the female characteristics and shrinking the bugs’ mouths could make them unable to pass on diseases.

Nearly half the world’s population is at risk of malaria, with around 212million cases and 429,000 deaths in 2015 alone, according to the World Health Organisation (WHO).

According to a report by the National Public Radio, tweaking the creature’s sexual development could save countless lives – particularly in Africa.

Entomologist Ruth Mueller, who runs the operation, says the mosquitoes’ genes could be edited using a technique called CRISPR – essentially cutting and pasting DNA.

And the DNA is edited in a way which makes sure the extra male characteristics are passed on to all offspring.

The effect will spread and accumulate until eventually mosquitoes born from two mutated parents will be unable to bite or reproduce at all.

“The females become a bit more male,” Mueller says. “A kind of hermaphrodite.”

As more and more female mosquitoes inherit two copies of the modification, more and more become sterile, the NPR add.

Animal and environmental activists have criticised the initiative, but Dr Mueller insists that modified mosquitoes would only affect one of hundreds of mosquito species.

But experts insist the test is ethical because it remains in a controlled environment.

Currently, the sample mosquitoes are kept in secure conditions.

Only if they were deemed safe would they be released into African villages, where they could spread their self-destruct gene and slash the insect population.

Supporters, including The Bill & Melinda Gates foundation, believe the benefits outweigh any negatives, which could include pollination issues.

“Malaria is a huge problem affecting probably two-thirds of the world’s population,” says Tony Nolan, who helped develop the mosquitoes at Imperial College London.

“There’s going to be concerns with any technology. But I don’t think you should throw out a technology without having done your best to understand what its potential is to be transformative for medicine. And, were it to work, this would be transformative.”

Researchers found the insects given drugs containing NPY-like receptors were less likely to suck blood when they were presented with a human arm. These receptors regulate appetite in everything from roundworms to humans, and are even used in experimental anti-obesity medication to curb our desire for food.

Scientists believe if female mosquitoes could be coaxed into receiving these drugs, it may help control deadly diseases with limited treatment options.

The research, detailed earlier this month, was carried out by The Rockefeller University in New York and led by Professor Leslie Vosshall, from the laboratory of neurogenetics and behavior.

After a female feeds, she stops seeking blood for several days while she allows her eggs to mature.

Certain peptides – which make up proteins – have been shown to activate NPY-like receptors. These suppress a mosquito’s appetite after she has fed.

NPY-like receptors have also been shown to influence food intake, fullness and obesity in humans.