Thursday August 22, 2019
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Infertility gene in mosquitoes to curb malaria


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)


Next Story

Most Effective Drug Used to Treat Malaria Becoming Ineffective in Parts of Southeast Asia

The report warns that the parasite Plasmodium falciparum — which causes the most lethal form of human malaria

Drug, Malaria, Asia
FILE - A public health worker takes a blood sample from a woman to be tested for malaria in Bo Rai district, Trat provice, Thailand. VOA

Scientists warn the most effective drug used to treat malaria is becoming ineffective in parts of Southeast Asia — and unless rapid action is taken, it could lead to a global health emergency.

Writing in the Lancet journal, researchers from Thailand’s Mahidol University and Britain’s Oxford University say parasites that carry malaria are developing resistance to a key drug combination across multiple regions of Cambodia, Laos, Thailand and Vietnam.

The report warns that the parasite Plasmodium falciparum — which causes the most lethal form of human malaria — is becoming resistant to the first-choice drug, DHA-piperaquine, in parts of Southeast Asia, with patients seeing a failure rate of 50 percent or more.

The situation is so critical that scientists say the treatment should not be used in Cambodia, Vietnam and northeast Thailand, because it is ineffective and contributes to increased malaria transmission.

Drug, Malaria, Asia
Scientists warn the most effective drug used to treat malaria is becoming ineffective in parts of Southeast Asia — and unless rapid action is taken. Pixabay

New treatments must be considered, says Sterghios Moschos of the University of Northumbria.

“It might be opportune at this point in time to explore whether or not we should bring together different new classes of medications so that when the problem starts becoming more substantial, there is a solution potentially that works at the multi-drug level,” said Moschos.

The report says urgent action is now needed to eliminate falciparum malaria from the region — otherwise the resistant strains of the parasite could further spread to other parts of Asia and Africa, potentially causing global health emergency.

“All it takes is a ship with infected individuals, or a pool of water where mosquitoes are, getting into Africa and then slowly that parasite establishing a foothold,” he added. “The likely scenario, however, will be that improvement of health care on a day-to-day basis in Africa will create the opportunity for the parasite to evolve resistance.”

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Currently, malaria vaccine trials are under way in several African countries. But drug combinations like DHA-piperaquine remain vital in treating malaria — especially in countries with poor health systems.

Since 2014, global progress against malaria has stalled. There were an estimated 219 million cases and 435,000 related deaths in 2017, most of them children under the age of five in sub-Saharan Africa. (VOA)