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Infertility gene in mosquitoes to curb malaria

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London: For the first time, researchers led by the Imperial College London, have genetically modified malarial mosquitoes so that they carry a gene that disrupts egg production in female mosquitoes.

They used a technology called “gene drive” to ensure the gene for infertility is passed down at an accelerated rate to offspring, spreading the gene through a population over time and raising the possibility of reducing the spread of disease.

Within a few years, the spread could drastically reduce or eliminate local populations of the malaria, carrying mosquito species.

The mosquito species Anopheles gambiae is a major carrier of malaria parasites in sub-Saharan Africa, where 90 per cent of annual malaria deaths occur.

Malaria infects over 200 million people each year and causes more than 430,000 deaths.

“Scientists have been trying to tackle malaria for more than 100 years. If successful, this technology has the potential to substantially reduce the transmission of malaria,” said study co-author professor Andrea Crisanti.

Normally, each gene variant has 50 per cent chance of being passed down from parents to their offspring.

In the team’s experiments with Anopheles gambiae, the gene for infertility was transmitted to more than 90 per cent of both male and female mosquitoes’ offspring.

The technique uses recessive genes so that many mosquitoes will inherit only one copy of the gene.

Two copies are needed to cause infertility, meaning that mosquitoes with only one copy are carriers, and can spread the gene through a population.

This is the first time the technique has been demonstrated in Anopheles gambiae.

The team targeted three different fertility genes and tested each for their suitability for affecting a mosquito population through gene drive, demonstrating the strength and flexibility of the technique to be applied to a range of genes.

“As with any new technology, it will be at least 10 more years before gene drive malaria mosquitoes could be a working intervention,” added professor Austin Burt from Imperial’s department of life sciences.

There are roughly 3,400 different species of mosquitoes worldwide.

“While Anopheles gambiae is an important carrier of malaria, it is only one of around 800 species of mosquito in Africa, so suppressing it in certain areas should not significantly impact the local ecosystem,” noted lead author Dr Tony Nolan.

The team aims to improve the expression of their gene drive elements. Exploring target genes is also helping the researchers to learn more about basic mosquito biology.

The results were published in the journal Nature Biotechnology.(ians)

(picture credit:upload.wikimedia.org)

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Brian Gitta: A Malaria Test That Would Not Need Blood Samples

The new malaria test kit works by shining a red beam of light onto a finger

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A health service worker takes a blood sample for a malaria test in Dajabon, Dominican Republic, on the border with Haiti, Oct. 6, 2009. A test that doesn't require a needle or blood has won the Africa Prize for Engineering Innovation
A health service worker takes a blood sample for a malaria test in Dajabon, Dominican Republic, on the border with Haiti, Oct. 6, 2009. A test that doesn't require a needle or blood has won the Africa Prize for Engineering Innovation, VOA

Languishing with fever and frustrated by delays in diagnosing his illness, Brian Gitta came up with a bright idea: a malaria test that would not need blood samples or specialized laboratory technicians.

That inspiration has won the 25-year-old Ugandan computer scientist a prestigious engineering prize for a noninvasive malaria test kit that he hopes will be widely used across Africa.

For developing the reusable test kit known as Matibabu, Gitta this month was awarded the Africa Prize for Engineering Innovation. The award by the Royal Academy of Engineering in Britain comes with $32,940.

Malaria is the biggest killer in Africa, and the sub-Saharan region accounts for about 80 percent of the world’s malaria cases and deaths. Cases rose to 216 million in 2016, up from 211 million cases in 2015, according to the latest World Malaria Report, released late last year. Malaria deaths fell by 1,000, to 445,000.

The mosquito-borne disease is a challenge to prevent, with increasing resistance reported to both drugs and insecticides.

No needles

The new malaria test kit works by shining a red beam of light onto a finger to detect changes in the shape, color and concentration of red blood cells, all of which are affected by malaria. The results are sent within a minute to a computer or mobile phone linked to the device.

A Portugal-based firm has been contracted to produce the components for Matibabu, the Swahili word for “treatment.”

“It’s a perfect example of how engineering can unlock development, in this case by improving health care,” Rebecca Enonchong, Africa Prize for Engineering Innovation judge, said in a statement. “Matibabu is simply a game changer.”

A woman carrying a baby holds a treated mosquito net during a malaria prevention action at Ajah in Eti Osa East district of Lagos, Nigeria, April 21, 2016.
A woman carrying a baby holds a treated mosquito net during a malaria prevention action at Ajah in Eti Osa East district of Lagos, Nigeria, April 21, 2016. VOA

Gitta and five colleagues, all trained in computer science or engineering, developed an affordable, bloodless test that does not need a specialist to operate. The new test will be suitable for use in Africa’s rural areas, where most cases of malaria occur, because it will not depend on sending blood samples to a distant laboratory.

Others are also working to fill the need for quicker, easier malaria tests. There are more than 200 rapid diagnostic test products for malaria on the market, according to the WHO.

80 percent accurate now

The fifth-generation prototype of Matibabu, with an accuracy rate of 80 percent, is still a work in process. Gitta and his group aim to refine the device until it achieves an accuracy rate exceeding 90 percent.

Matibabu has yet to be formally subjected to all the necessary clinical trials under Ugandan safety and ethics regulations.

“It excites me as a clinician,” said Medard Bitekyerezo, a Ugandan physician who chairs the National Drug Authority. “I think the National Drug Authority will approve it.”

The government should invest in the project so that its developers don’t struggle financially, he added. The unit cost of the latest prototype is about $100.

Despite the optimism, Gitta has found a hurdle he didn’t anticipate: Some patients are skeptical of unfamiliar technology.

“The doctors will tell you that some people will not leave the hospital until their children have been pricked, and until they have been given anti-malaria drugs and painkillers, even if the kid is not sick,” he said.

Also read: From Radio Signals A Pill Could Tell About Gut Health And Help Doctors

“We think we are developing for hospitals first, so that people can first get attached to the brand, and gain the trust of patients over time.” (VOA)