Scientists eradicate malaria-transmitting mosquitoes using genetic engineering

Malaria kills nearly 500,000 people worldwide each year, but scientists have now devised a way to use CRISPR gene-editing technology to render female mosquitoes infertile, which has been described as a “game-changer” for ending the deadly disease.

Researchers from Imperial College London, Genomics Genetics and Biology and the Liverpool School of Tropical Medicine were able to use a gene drive for the first time to show that blocking female reproduction worked not only in a lab setting, but also in a natural setting.

The researchers focused on the mosquito species Anopheles gambiae, which is responsible for most malaria transmissions in sub-Saharan Africa.

The gene drives target the gene known as ‘doublesex’ in these mosquitoes.

Scientists used CRISPR gene editing technology to render female mosquitoes sterile. Researchers used a gene drive in a natural environment for the first time

The gene drives target the gene known as 'doublesex' in these mosquitoes

The gene drives target the gene known as ‘doublesex’ in these mosquitoes

In the new study, in the real world, there was a “complete suppression of the population within 560 days,” with 95 percent of the simulations reaching a state with no more offspring in 399 and 329 days “for the low and high gene drive frequency.” -releases, respectively.’

In a previous study in 2018, the researchers put nearly 600 mosquitoes in a small cage and once the gene drive was used, no more offspring were produced within 7 to 11 generations.

“The challenges to malaria elimination have intensified in recent years, due in part to the spread of insecticide resistance and large funding gaps in parts of sub-Saharan Africa,” said the study’s co-author, Imperial College. London and Johns Hopkins Malaria Research. Institute scientist Dr Drew Hammond in a pronunciation.

There was a 'complete suppression of the population within 560 days.  95 percent of simulations saw no offspring after 399 and 329 days with low and high gene drive frequency releases

There was a ‘complete suppression of the population within 560 days. 95 percent of simulations saw no offspring after 399 and 329 days with low and high gene drive frequency releases

“Unfortunately, researchers estimate that COVID-19-related disruptions may have doubled mortality from malaria by 2020, threatening a setback of decades.

“Gene drive is a self-sustaining and fast-acting technology that can work alongside existing tools such as mosquito nets, insecticides and vaccines – and be a game-changer in achieving the elimination of malaria.”

In an interview with the guardHammond said gene drive technology “could be a game-changer in achieving malaria elimination.”

Although there are more than 3,500 mosquito species worldwide, only a small proportion of them transmit malaria.

In 2019, there were 229 million cases of malaria and 409,000 deaths, with children under 5 being the most vulnerable, according to the World Health Organisation.

Last month, the WHO declared China malaria-free after successfully implementing its 1-3-7 strategy. In the 1940s, China routinely reported 30 million cases a year.

The life cycle of the parasite, Plasmodium, that causes malaria

The life cycle of the parasite, Plasmodium, that causes malaria

The researchers hope a mosquito with the gene drive could be released in the future and eventually spread the tweak to female mosquitoes and lead to infertility of the species.

“The gene drive element quickly spreads through populations, completely suppressing the population within a year and without selecting for resistance to the gene drive,” the researchers wrote in the study summary.

The new cages are designed to produce ‘complex mating and oviposition behaviour’, such as egg-laying, which were not available in the previous small cages.

The temperature and humidity in the cage were monitored, and the researchers placed natural landmarks and specialized lighting designed to simulate sunrise and sunset to trigger swarms.

Each of the large cages showed “rapid spread of gene drive and complete population collapse within a year,” the statement added.

There is concern about gene drives as mutations can become resistant to technology, but the experts said this strain is the first and only one to show no signs of resistance.

‘Our studies in large cages increase the selection pressure for gene drive resistance to emerge, as there may be additional ‘fitness costs’ when the mosquitoes display natural mating and egg-laying behaviors that are influenced in ways we could not. predicting studies in small cages,” said study co-lead authors, Dr. Tania Persampieri and Paola Pollegioni.

“However, no changes have occurred that could render the mosquito’s double-sex gene resistant to our gene drive, suggesting that our modification that causes female infertility is robust.”

The findings were published earlier this week in nature communication.

WHAT IS MALARIA?

Malaria is caused by a parasite called Plasmodium, which is mainly spread by the bite of the female Anopheles mosquito

Malaria is caused by a parasite called Plasmodium, which is mainly spread by the bite of the female Anopheles mosquito

Malaria is a life-threatening tropical disease spread by mosquitoes.

It is one of the world’s biggest killers, claiming the life of a child every two minutes, according to the World Health Organization (WHO).

Most of these deaths occur in Africa, where 250,000 young people die each year from the disease.

Malaria is caused by a parasite called Plasmodium mainly spread by the bite of the female Anopheles mosquito.

Symptoms that usually appear between a week and 18 days after infection includeever, chills, headache, vomiting, muscle aches and ddiarrhea.

People should seek immediate medical attention if they develop symptoms during or after visiting a malaria-affected area.

Malaria occurs in more than 100 countries, including:

  • Large parts of Africa and Asia
  • Central and South America
  • Haiti and the Dominican Republic
  • Parts of the Middle East
  • Some Pacific Islands

Malaria can be largely prevented by using insect repellent, wearing clothes that cover your limbs, using an insecticide-treated mosquito net, or by taking doxycycline or other malaria prevention medications.

Treatment includes anti-malarial medication and usually leads to full recovery if done early enough.

Left untreated, the infection can lead to severe anemia. This happens when the parasites invade red blood cells, which then rupture and generally reduce the number of cells.

And cerebral malaria can occur when the small blood vessels in the brain become blocked, leading to seizures, brain damage and even coma.

Source: NHS Choices

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