Malaria mosquitoes wiped out in lab trials of gene drive technique

UNTV News   •   October 15, 2018   •   1767

FILE PHOTO: Anopheles minimus mosquitoes are pictured at a lab in the Public Health Ministry in Bangkok, Thailand, November 9, 2017. REUTERS/Athit Perawongmetha/File Photo

 

LONDON (Reuters) – Scientists have succeeded in wiping out a population of caged mosquitoes in laboratory experiments using a type of genetic engineering known as a gene drive, which spread a modification blocking female reproduction.

The researchers, whose work was published on Monday in the journal Nature Biotechnology, managed to eliminate the population in less than 11 generations, suggesting the technique could in future be used to control the spread of malaria, a parasitic disease carried by Anopheles gambiae mosquitoes.

“It will still be at least five to 10 years before we consider testing any mosquitoes with gene drive in the wild, but now we have some encouraging proof that we’re on the right path,” said Andrea Crisanti, a professor at Imperial College London who co-led the work.

The results mark the first time this technology has been able to completely suppress a population. The hope is that in future, mosquitoes carrying a gene drive could be released, spreading female infertility within local malaria-carrying mosquito populations and causing them to collapse.

Gene drive technologies alter DNA and drive self-sustaining genetic changes through multiple generations by overriding normal biological processes. The technologies can be very powerful, but they are also controversial, since such genetically engineered organisms released into the environment could have an unknown and irreversible impact on the ecosystem.

The technique used in this study was designed to target the specific mosquito species Anopheles gambiae that is responsible for malaria transmission in sub-Saharan Africa.

The World Health Organization has warned that global progress against malaria is stalling and could be reversed if momentum in the fight to wipe it out was lost.

The disease infected around 216 million people worldwide in 2016 and killed 445,000 of them. The vast majority of malaria deaths are in babies and young children in sub-Saharan Africa.

Crisanti’s team designed their gene drive to selectively alter a region of a so-called “doublesex gene” in the mosquitoes, which is responsible for female development.

Males who carried this modified gene showed no changes, and neither did females with only one copy of it, he explained in the study. But females with two copies of the modified gene showed both male and female characteristics – they failed to bite and did not lay eggs.

The experiments found the gene drive transmitted the genetic modification nearly 100 percent of the time, and after 7-11 generations the populations collapsed due to lack of offspring.

Crisanti said the results showed that gene drive solutions can work, offering “hope in the fight against a disease that has plagued mankind for centuries”.

He added, however, that “there is still more work to be done, both in terms of testing the technology in larger lab-based studies and working with affected countries to assess the feasibility of such an intervention”.

But Mariann Bassey, a campaigner with the environmental group Friends of the Earth Africa, said the technique was risky.

“To solve the malaria crisis, we should focus on the least risky and most effective solutions, not experiment with ecosystems with little regard for the potentially new environmental and health consequences,” she said in a statement.

Reporting by Kate Kelland; Editing by Matthew Mpoke Bigg

WHO approves first malaria vaccine, recommends use for children

Aileen Cerrudo   •   October 7, 2021

The World Health Organization (WHO) has approved the first malaria vaccine and has recommended its use among children.

WHO Director-General Dr Tedros Adhanom Ghebreyesus said the use of this vaccine could save tens of thousands of young lives each year. The recommendation is based on results from an ongoing pilot program in Ghana, Kenya and Malawi.

“This is a historic moment. The long-awaited malaria vaccine for children is a breakthrough for science, child health and malaria control,” he said.

The agency is recommending the use of RTS,S/AS01 (RTS,S) malaria vaccine among children in sub-Saharan Africa and in other regions, based on the advice of two WHO global advisory bodies.

For the vaccination, the WHO also said the vaccine should be administered in areas with moderate to high transmission as defined by the agency. Malaria vaccine should be provided in a schedule of 4 doses in children from 5 months of age for the reduction of malaria disease and burden.

Meanwhile, financing for the pilot program has been mobilized. AAC

 

 

Four reasons why Africa, Gates and Obama want to end malaria

admin   •   June 10, 2016

File photo of a Zambian healthcare worker checking a malaria test during the Roll Back Malaria Zambezi Expedition in Matongo village, about 60 km (37 miles) from Livingstone, April 23, 2008.

File photo of a Zambian healthcare worker checking a malaria test during the Roll Back Malaria Zambezi Expedition in Matongo village, about 60 km (37 miles) from Livingstone, April 23, 2008.

ARUSHA, Tanzania (Thomson Reuters Foundation) – The world’s richest couple, Bill and Melinda Gates, and U.S. President Barack Obama are giving financial backing to global plans to eliminate malaria.

The Gateses aim to eradicate malaria by 2040 by doubling funding over the next decade to support the roll out of new products to tackle rising drug resistance to the disease.

Their goal of permanently ending transmission of the disease between humans and mosquitoes is more ambitious than the Sustainable Development Goal of ending epidemic levels of malaria by 2030.

They are also supporting a push to create the world’s first vaccine against a parasite.

Here are four of their arguments for pouring money into the issue:

* It promises almost a 20-fold return on investment: Eradication could save 11 million lives and unlock $2 trillion in economic benefits by 2040 from a healthy, more productive workforce and health systems that are less burdened by the disease, Gates and the United Nations say.

They estimate eradication would cost a fraction of this — $90 billion to $120 billion, making it one of the “best buys” in global development.

* It’s the only way to deal with drug-resistance: If malaria is not eliminated from drug resistant “hot spots” in Cambodia, Laos, Myanmar, Thailand and Vietnam, multi-drug resistant malaria is likely to spread worldwide, increasing the cost and reducing the efficacy of malaria control programs everywhere.

Donors have set a goal of eliminating malaria in this Greater Mekong region by 2020.

Tanzania’s health ministry’s acting permanent secretary, Nkundwe Mwakyusa, said the emergence and spread of resistance to artemisinin, the most commonly used drug against malaria, in Asia was “a major concern”.

In parts of Tanzania, mosquitoes can survive up to 20 times the normal dose of permethrin, the insecticide used in nets, according to Sophie Weston, a researcher with the London School of Hygiene and Tropical Medicine.

* More children in school, less in hospital: Trials of the Mosquirix vaccine showed that young children in countries like Kenya fall sick with malaria up to five times in one year.

Malaria is one of the main reasons why Africans miss school or work, entrenching poverty as time and money are spent in hospital, rather than learning or earning.

More than half of the deaths of children under five in Tanzanian health facilities are due to malaria, according to the United States’ President’s Malaria Initiative (PMI).

Malaria in pregnancy also causes about a quarter of all underweight births in Africa, according to campaign group Malaria No More.

This translates to about 100,000 neonatal deaths a year, and underweight children tend to suffer poor health.

“There’s so much talk about zika and the terrifying effects during pregnancy but just in sheer scale, malaria outstrips it many times over,” said Martin Edlund, chief executive of Malaria No More.

* It frees up money for “the next epidemic”: Malaria is no longer the leading cause of death among children under five in Africa, having been overtaken by acute respiratory infections, according to PMI.

It still accounts for a third of outpatient visits on mainland Tanzania, 7.3 million cases a year, it says.

“The next step is … to focus also on non-communicable diseases,” said Mohamed Alwani, medical director of Ithani-Asheri Hospital in the Tanzanian town of Arusha, referring to heart disease, diabetes and cancer.

“The way I can see it for the last five years or so now, it’s going to be the next epidemic.”

The International Center for Journalists and Malaria No More provided a travel grant for this report

(Reporting by Katy Migiro; Editing by Katie Nguyen.; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women’s rights, trafficking, property rights and climate change. Visit news.trust.org to see more stories.)

In the lab: six innovations scientists hope will end malaria

admin   •   June 8, 2016

 An Anopheles stephensi mosquito obtains a blood meal from a human host through its pointed proboscis in this undated handout photo obtained by Reuters November 23, 2015. REUTERS/Jim Gathany/CDC/Handout via Reuters An Anopheles stephensi mosquito obtains a blood meal from a human host through its pointed proboscis in this undated handout photo obtained by Reuters November 23, 2015. REUTERS/JIM GATHANY/CDC/HANDOUT VIA REUTERS


An Anopheles stephensi mosquito obtains a blood meal from a human host through its pointed proboscis in this undated handout photo obtained by Reuters November 23, 2015. REUTERS/Jim Gathany/CDC/Handout via Reuters
An Anopheles stephensi mosquito obtains a blood meal from a human host through its pointed proboscis in this undated handout photo obtained by Reuters November 23, 2015.
REUTERS/JIM GATHANY/CDC/HANDOUT VIA REUTERS

ARUSHA, Tanzania (Thomson Reuters Foundation) – After being abandoned as too ambitious in 1969, global plans to eliminate malaria are back on the agenda, with financial backing from the world’s richest couple, Bill and Melinda Gates, and U.S. President Barack Obama.

The Gateses aim to eradicate malaria by 2040 by doubling funding over the next decade to support the roll out of new products to tackle rising drug resistance against the disease.

Their goal of permanently ending transmission of the disease between humans and mosquitoes is more ambitious than the Sustainable Development Goal of ending epidemic levels of malaria by 2030.

They are also supporting a push to create the world’s first vaccine against a parasite.

Six innovations scientists are working on are:

* New insecticides: Mosquitoes are becoming resistant to insecticides used to spray inside homes and in bed nets.

“There is no current insecticide that doesn’t show insect-resistance at the moment,” said Jed Stone, a spokesman for the UK-based Innovative Vector Control Consortium (IVCC).

Indoor spraying of walls with insecticide — which was used to wipe out malaria in the United States in the 1940s — has fallen by 40 percent since 2012 due to resistance to older products and the high cost of newer ones.

The IVCC is developing three new insecticides for use in indoor sprays and bed nets that kill insecticide-resistant mosquitoes.

“The insecticides are virtually ready but it will take about five years to finally develop them,” Stone said, adding that this largely involves registration with regulators.

* A single-dose cure: A pill that would wipe out all parasites in the body could be available by 2019, the Gates Foundation says.

Human trials of one candidate are planned following successful tests on mice, published in 2015.

Existing drugs have to be taken for three days with the risk that people do not finish their medication, contributing to the development of drug-resistant malaria.

They also only kill parasites at the asexual-stage where they cause fever but not at the sexual-stage where they are picked up by mosquitoes in blood.

* Insecticide-treated wall liners: Scientists hope insecticide-treated wall liners, which look like wallpaper, will be more effective than spraying people’s homes with insecticide every three to eight months. The wall liners kill mosquitoes that rest on them and can last for three years.

Tanzania’s National Institute for Medical Research is testing wall liners in 6,000 homes to see if they protect people from malaria. Results will be published in 2017.

* Insecticide-embedded clothing: American soldiers have been wearing combat uniforms treated with permethrin, a synthetic insecticide, since 2010 to protect them against insect-borne diseases.

The U.S. government’s Walter Reed Army Institute of Research will test the effectiveness of treated combat uniforms and repellent creams in July on Tanzanian soldiers who often catch malaria when working at night as peacekeepers.

* A vaccine: This is a big one, given vaccines success in eliminating smallpox, polio and measles in many countries.

More than 30 malaria vaccines are under development.

The Mosquirix vaccine, discovered in 1987, is a decade ahead of other candidates but, to date, it only halves the number of bouts of malaria young children suffer.

The World Health Organization is seeking funding for a pilot program to administer Mosquirix to 400,000 to 800,000 African children. The results will be used to make a decision on whether to use the vaccine more widely.

* GM mosquitoes: Scientists have genetically modified (GM) mosquitoes by adding genes that block the development of the malaria parasite inside the insect and prevent it from being transmitted to people.

Scientists have also genetically modified mosquitoes to make them infertile, so that they die out. But many are cautious about the unforeseen consequences of this.

“When people imagine a malaria end game scenario, GM mosquito technology would be incredibly powerful because it doesn’t rely on a robust health system in order to go in and disrupt transmission of the parasite,” said Martin Edlund, chief executive of Malaria No More, referring to war-torn countries like South Sudan.

The International Center for Journalists and Malaria No More provided a travel grant for this report

(Reporting by Katy Migiro; Editing by Katie Nguyen; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women’s rights, trafficking, property rights and climate change. Visit news.trust.org to see more stories.)

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