Mosquitoes are one of the primary ways that malaria spreads across the globe, and mosquitoes are also responsible for killing around 830,00 people every year by some estimates. If these estimates are accurate, that makes these parasites one of the deadliest creatures on Earth. The Bill and Melinda Gates Foundation has donated a large amount of money to fund the engineering of a type of mosquito that would help stop the spread of malaria.
The Return Of Malaria
While mosquitoes can carry a number of different diseases, malaria is responsible for the vast majority of deaths from mosquitoes, killing around 440,000 people every year. Malaria is transferred from person to person when a mosquito drinks the blood of an infected person and then drinks the blood of another person. Cases of malaria had fallen dramatically, by around 62% between 200 to 2015, but now the disease seems to be making a return and malaria cases have spiked all around the globe.
Pedro Alonso, the director of the Global Malaria Programme run through the World Health Organization explains that humanity has ceased making progress in its fight against malaria. One possible cause is that as rates of malaria plummeted world governments shifted their focus and ceased funding malaria eradication projects in favor of other projects. Some scientists also think that the revival of malaria may be due to the development of drug-resistant strains of the disease.
Bio-Engineering To Fight Malaria
The Bill and Melinda Gates Foundation has committed itself to eradicating malaria since the foundation was originally created back in 2000. All told, the foundation has pledged around $2 billion dollars to fight malaria. The foundation recently added to that sum with a pledge of around $4.1 million dollars towards a bio-engineering project that would kill off many of the mosquitoes that carry malaria.
The engineering project would essentially create a batch of male mosquitoes that would kill their offspring and prevent mosquito populations from thriving. The foundation announced that they would be partnering with UK-based genetic engineering company Oxitec to create the new mosquitoes which they have dubbed ”Friendly Mosquitoes”.
The Friendly Mosquitoes work by mating with natural wild, malaria-carrying mosquitoes and passing onto their offspring a gene that kills off future generations of female mosquitoes before they mature into adulthood. This approach is used because only female mosquitoes bite people, and if the gene kills them before they reach the age where they can bite people they won’t spread malaria. Crucially though, the new generation of males could conceivably go on to mate with other females and then breed with them, releasing this self-limiting gene and killing off female mosquitoes for up to ten generations.
Other “Friendly Mosquitoes” have been utilized in the past to fight the Zika virus, yellow fever, and dengue. The engineered mosquitoes were of the Aedes aegypti species, and the populations were released into Brazil, Panama, and the Cayman Islands. They’ve also been used in caged trials in India. The engineered mosquitoes have had an astonishing success rate in the areas where they were deployed, reducing populations of mosquitoes carrying Zika and yellow fever by around 90%. The Gates Foundation had also backed this project back in 2010.
Complications And Conversations
Despite the success rate, there were also some complications. One of the trials that sought to combat yellow fever in Panama found that even though the engineers released approximately one genetically-engineered female for every 10,000 males that it released, the females ended up being disease free and died in a matter of days.
Oxitec has reported that their new batch of Friendly Mosquitoes will hopefully be ready for field trials by the fall of 2020. However, the company is grappling with resistance from those who are concerned about its use of genetic engineering. Oxitec hopes that they will be able to utilize some of their previously engineered mosquitoes in areas of the Florida Keys over the summer, though residents of the Keys have voiced resistance against the projects in the past. During 2016 residents of the Florida Keys voted against the use of genetically modified mosquitoes. In response to this, Oxitec has lead a number of town hall meetings and met with civil officials in the Keys, hoping to sway the neighborhoods that were against their plans two years ago.
Oxitec is hardly alone in the plan to use genetically modified mosquitoes to fight malaria and other diseases. Other researchers, universities and companies are also conducting research into the use of modified mosquitoes. Researchers at Imperial College London have also been hard at work on a mutation to sterilize female mosquitoes that carry malaria, involving the creation of a gene drive that would spread quickly throughout a population, so that almost all the offspring would have the modified gene. The ICL team is using the well-known bio-engineering system CRISPR (Cas-9 Genome Editing) to make changes to the genome of the mosquitoes. The mosquitoes are still being developed by the ICL team and not ready for deployment yet.
The genetic engineering projects of Oxitec and other companies have received criticism from environmentalist groups like Friends of the Earth. The primary argument against the project is that it isn’t clear how releasing mosquitoes that would kill off large mosquito populations would affect the larger ecosystem, being that many animals, like fish and frogs, rely on mosquitoes for food. The worry is that the genetically engineered mosquitoes could reduce mosquito populations and end up killing other animals.
Researchers who work on the bio-engineering projects understand the concerns but argue that the number of mosquito populations that would be affected by their engineering is quite small. Bio-engineers argue that they will only be targeting mosquito populations that have an active role in spreading diseases like malaria and Zika virus, their intention isn’t to kill off all mosquitoes.
Molecular biologist Tony Nolan, works on the mosquitos bio-engineering project at Imperial College London, and says that the elimination of global mosquito populations as a result of their work is far-fetched. Nolan argues that realistically, there would only be a reduction in certain local populations. It’s possible that other species of mosquitoes may fill in the ecological niche left behind by the targeted populations of mosquitoes. Says Nolan:
If we succeed, people won’t even notice. There will be plenty of mosquitoes out there.