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What if you could use genetic engineering to stop humanity’s most

dangerous predator, the deadliest animal on the planet responsible for the death

of billions, the mighty mosquito? Along with other diseases it plays host to

Malaria, one of the cruelest parasites on Earth

possibly the single biggest killer of humans in history.

In 2015 alone

hundreds of millions were infected and almost half a million people died.

A new technology could help us eradicate Malaria forever, but to do so we need to

engineer a whole animal population.

This is not a hypothetical problem, the modified mosquitoes already exist in a lab.

Should we use the technology, and is malaria bad enough to risk it?

(Intro Music)

Malaria is caused by a group of microorganisms: Plasmodia, very weird

microorganisms that consists of just a single-cell, they’re parasites that

completely rely on mosquitoes. Malaria always starts with an insect bite.

In it’s salivary glands, thousands of sporozoites wait until the insect penetrates your

skin, immediately after invading you they head for the liver where they quietly

enter big cells and hide from the immune system. For up to a month they stay here

in stealth mode consuming the cells alive and changing into their next form:

small drop like merozoites, they multiply generating thousands of themselves and

then burst out of the cells. So thousands of parasites head into the bloodstream

to look for their next victims, Red blood cells, to stay unnoticed, they wrap

themselves in the membranes of the cells they killed. Imagine that! Killing someone

from the inside and then taking their skin as camouflage, brutal!

They now violently attack red blood cells, multiplying inside them until they burst

then finding more red blood cells and this cycle repeats over and over.

Pieces of dead cells spread lots of toxic waste material, which activates a powerful

immune response causing flu-like symptoms, among the symptoms are high

fever, sweats and chills, convulsions, headaches and sometimes vomiting and

diarrhea. If malaria breaches the blood-brain barrier it can cause coma,

neurological damage or death. The parasites are ready for evacuation now.

When another mosquito bites the infected human they get a ride, the cycle can

start over.

In 2015, the Zika virus, which causes horrible birth defects if it

infects pregnant women, spread rapidly into new areas around the globe. It too

is carried by a mosquito. The mosquito is the perfect carrier for human diseases

they’ve been around for at least 200 million years. There are trillions of

them and a single one can lay up to 300 eggs at a time. They are practically

impossible to eradicate and the perfect parasite taxi. But today we have a new

revolutionary technology, that could enable us to finally win the war

against them; CRISPR. For the first time in human history, we have the tools to

make fast, large-scale changes to entire species, changing their genetic

information as we please.

So instead of attacking isolated groups of insects, why not just change the

types that transmit diseases?

Using genetic engineering, scientists

successfully created a strain of mosquitoes that are immune to the

malaria parasite by adding a new antibody gene that specifically targets

plasmodium. These mosquitoes will never spread malaria. But just changing genetic

information is not enough. The edits would only be inherited by half the

offspring because most genes have two versions inside the genome as a

fail-safe. So after just two generations, at most only half of the offspring would

carry the engineered gene. In a population of billions of mosquitoes they would

hardly make a difference.

A genetic engineering method called the gene drive

solves this problem.

It forces the new gene to become dominant in the following generations

overpowering the old gene almost completely.

Thanks to this twist, 99.5% of all the engineered mosquitoes offspring will

carry the anti-malaria edit. If we were to release enough engineered mosquitoes

into the wild to mate with normal mosquitoes, the malaria blocking gene would spread

extremely quickly.

As the new gene becomes a permanent feature of the

mosquito population, Plasmodium would lose its home base.

Scientists hope that the change would be so fast that they could not adapt to it quickly enough.

Malaria could virtually disappear.

If you take into account that

maybe half a million children are killed by it every year, about five have died

since this video started. Some scientists argue that we should use the technology

sooner, rather than later.

The mosquitoes themselves would probably only profit from this, they don’t have

anything to gain from carrying parasites and this might only be the first step

Malaria might just be the beginning.

Different mosquitoes also carry Dengue

fever and Zika, ticks transmit Lyme disease, flies transmit sleeping sickness

fleas transmit the plague. We could save millions of lives and prevent suffering

on an unbelievable scale. So, why haven’t we done this yet?

For one, CRISPR editing is

barely four years old, so until very recently we just couldn’t do it as fast

and easily. And there are valid concerns.

Never before have humans consciously changed the genetic code of a free-living

organism on this scale.

Once we do it,

there is no going back. So it has to be done right, because there could be

unwanted consequences if we set out to edit nature.

In this specific case of malaria though, the risk might be acceptable

since the genetic modification doesn’t make a big change in the overall genome.

It only changes a very specific part.

The worst-case scenario here, is probably

that it might not work or that the parasite adapts in a negative way.

There is still much debate.

Technology as powerful as gene drive, needs to be

handled with a lot of care but at some point we have to ask ourselves: Is it

unethical to not use this technology, when every day 1,000 children die.

Humanity has to decide how to act on this in the next few years.

The public discussion is way behind the technology in this case.

What do you think?

This video was made possible in part by viewer donations on Patreon. If you want

to help us make more videos like this and get nice rewards in return you can

do so here. We really appreciate it. If you want to learn more about the topic

of genetic engineering, we have another video about CRISPR and GMOs, and in case

that’s too much biology for you, here’s a space playlist.