Mosquitoes Genetically Modified to Crash Species That Spreads Malaria | Hacker News Reader

Mosquitoes Genetically Modified to Crash Species That Spreads Malaria

npr.org

81 pointsamluto95 comments

To all the naysayers: Did you know that there were massive DDT campaigns to wipe out mosquitoes in Europe and the USA, which means you no longer suffer from malaria in Mississippi or Italy? Italy was only declared malaria-free in 1970.

The proposed measures have much lower environmental risks than the DDT ever did. Saying this shouldn't be used is effectively pulling up the ladder behind you. Go to Mozambique or DRC, get malaria, and then use the same health care the locals have access to. Hope to hell you don't have Cerebral Malaria (20% mortality rate with treatment). Then come back and complain about the environmental risks of wiping out 1 of over 15 mosquito species, which primarily feeds on humans anyways.

> a technology that no one could say is safe definitively

Problem with this type of technology is that there is no way to even test if it would be safe. You either have to just take the risk or not do it. And unfortunately someone else will likely take the risk even if we don't. So it makes more sense to me to try it and watch carefully.

BUT there is something that people aren't talking about much. This targeting isn't "kill all mosquitoes" it is "kill the mosquitoes that carry malaria" (Anopheles. Which are different from Aedes aegypti, which carry yellow fever, dengue fever, Zika fever and chikungunya). So doing this to Anopheles shouldn't affect the Aedes aegypti mosquito. So it is a tad safer than killing ALL the mosquitoes. But still potentially unsafe as other creatures may rely on them as a food source more than currently believed.

It also begs the question, can we try this out on a specific species that is far less widespread? Doesn't even have to be mosquitoes.

Disclaimer: Not a geneticist. If I stated something wrong please correct me! And please provide source material so I can read it. Thanks!

If they released this to eliminate Asian Tiger Mosquitoes from the USA it would be a perfect limited scope experiment. They have out competed other mosquitoes in my area and are invasive. They also spread disease and bite 24 hours a day making everyone's lives miserable outdoors. I wouldn't miss them at all. And there's not much life depending on eating Asian Tiger Mosquito larvae from trash with tiny pools of water. They don't make much of a meal for any animal or insect or we'd have far fewer.

It’s disturbing to realize that people here baying form this to be rolled out seemingly know very little about the topic. Mosquitoes aren’t just food for other insects, and bats, and birds, they’re also pollinators. In the context of how many insects and bees we’re killing by other means, it’s hard to predict how much of a critical role mosquitoes play in that regard. Insect numbers have been cratering lately, and kicking whole species off a cliff may not matter, or it may be a critical step. When considering these actions we have to remember just how much stress we are already putting on the food web, and how much more we’ll stress it in the future.

The tiger mosquito your parent mentions, though, is invasive. Ecologists are usually more than happy to target invasive species.

True, but in the context of a pilot program to target native species elsewhere. In short it wouldn’t meet that criteria, because the Asian Tiger mosquito is a recent invader. In the narrow case of targeting recent (decades rather than centuries, and then ATM qualifies as the former) invaders alone, I agree that few rational people would object.

> in the context of a pilot program to target native species elsewhere

Isn't this just defining the scope artificially narrowly to deny that it would be a useful experiment?

Is there an ecologically significant difference in targeting an invasive species?

Maybe some things are worth the risk.

We shouldnt sit around bioethicizing while people are dying of maleria.

Even if your premise is that we should prioritize human life above all else, there's still a very good reason to consider the effect of eliminating any species on the rest of the ecosystem before we just pull the trigger. It's really easy to imagine a scenario where eliminating this mosquito ends up being more harmful to human life than leaving it in place.

The effect has been considered, carefully, by a variety of researchers, and to date the majority of them have found no reason to believe there'd be more than the most negligible of effects on ecosystems. (When specifically eradicating the species that spread disease to humans.)

https://www.nature.com/news/2010/100721/full/466432a.html

https://www.bbc.com/news/magazine-35408835

https://www.smithsonianmag.com/innovation/kill-all-mosquitos...

https://outline.com/428REE

https://www.npr.org/sections/goatsandsoda/2016/02/20/4670944...

You can find some articles from researchers in the field that are concerned about removing them (https://phys.org/news/2017-07-mosquitoes.html), but those researchers don't seem to have done as much work in the role of individual mosquito species in their environments.

Similar to the Four Pests Campaign:

https://en.wikipedia.org/wiki/Four_Pests_Campaign

By April 1960, Chinese leaders changed their opinion due to the influence of ornithologist Tso-hsin Cheng[2] who pointed out that sparrows ate a large number of insects, as well as grains.[8][9] Rather than being increased, rice yields after the campaign were substantially decreased.[10][9] Mao ordered the end of the campaign against sparrows, replacing them with bed bugs, as the extermination of the former upset the ecological balance, and bugs destroyed crops as a result of the absence of natural predators. By this time, however, it was too late. With no sparrows to eat them, locust populations ballooned, swarming the country and compounding the ecological problems already caused by the Great Leap Forward, including widespread deforestation and misuse of poisons and pesticides.[10] Ecological imbalance is credited with exacerbating the Great Chinese Famine, in which 20–45 million people died of starvation.[11][12]

You say it's easy to imagine bad scenarios. Then state them, with sources.

I've read the exact opposite: That it's hard to find any _real_ risks for eliminating human-biting mosquitoes. I define real as killing near 3k children a day.

https://www.nature.com/news/2010/100721/full/466432a.html

Yes, here it is again, the nearly ten year old magazine article written by an intern. Nothing could be more definitive.

At least it's something. You're welcome to add some sources of your own to the discussion.

I agree that we should think about the ecosystem. But is that something we can reasonably model? From what I understand Anopheles isn't thought to be essential. Plus, this demonstration would show we could do similar things with other similarly dangerous and potentially non-essential animals.

Though a counterpoint, malaria was eradicated from Europe without eradicating Anopheles.

Europe is not tropical.

I'm not sure what that has to do with the topic at hand. Malaria was eradicated from Europe by a lot of stuff that happens when a country moves into a first world economy. Eg: Window screens (a mosquito net for your whole house!), less stagnant water spots (breeding zones), better health care, etc. Malaria was eradicated from Europe because the Plasmodium couldn't reproduce in large enough quantities.

We've eliminated hundreds, if not thousands of species, like the Dodo Bird, through human actions. What's one more?

This is exactly the mentality the hand-wringers are terrified is out there.

Early vaccines got the dosage wrong and sometimes killed people... I think in this day and age if something similar happened, it'd be pulled off the shelves, and tens of thousands of lives would be lost due to it being unavailable.

Progress = risk. Yes, it should be measured and thoughtful, but overreaction seems rampant.

It's even worse than you're making out, actually. I'm all for eliminating malaria, or mosquitoes, or whatever. And I'm generally in favor of GMOs and related technologies. However, the described approach uses a gene drive, meaning genetic modifications are transmitted in the wild through the target species.

> So doing this to Anopheles shouldn't affect the Aedes aegypti mosquito.

If all goes according to plan, at least. But good luck containing things if they don't...

It really shouldn't require any help from Hollywood to see the potential failure cases that this sort of technology entails - incredibly thorough testing is merely the absolute minimum requirement.

Trust us, pyrus calleryana- sorry, I mean anopheles gambiae- definitely won't crossbreed with anything.

Had to look that one up, that's a really good example of the sort of unexpected complexities that can come up (many years later in this case).

For others (like myself) who haven't seen it before: https://academic.oup.com/bioscience/article/57/11/956/234351

> Consequently, individual cultivars themselves are not invasive, but the combination of cultivars within an area creates a situation in which invasive plants can be produced.

I fully agree that it is a horrendously difficult problem. But from cross breeding, most of the time the offspring is sterile. Like a mule or liger. But you're right, things often don't go according to plan.

But there is an overwhelming amount of scientists, who are smarter than me and actually study this, that believe it is worth the risk. I'm willing to put my trust into their judgement. Btw, there has been a LOT of testing. But what I mentioned in the OP was more about that at a certain point you have to take a leap of faith.

After having mosquitos invade my house this summer: please kill any mosquitos that bite people and carry disease. I don't care. We've unintentionally wiped out multitudes of interesting, beautiful species that did nothing to harm us, and it's revolting to observe that we're hemming and hawing about taking out the worst species in the history of the planet.

> "It could lead to other species coming in to fill a niche that are even more a problem," Steinbrecher says. "It's beyond our ability to predict what the consequences are, except that it could be really devastating."

Malaria has killed more people than all wars in human history combined. Hundreds of thousands, if not millions, are going to die while we come up with reasons not to do anything about it.

A. gambiae in particular is so strongly anthropophilic that it would likely become endangered or extinct if cut off from all human hosts, so a widespread bed-netting program would have likely the same effect, just slower and with millions more cases of malaria in the meantime.

Any naysayers out there interested in volunteering for blood-feeding? Our current approach of "make the poor people do it" isn't exactly fair.

The application is fine, unfortunately the real danger is the technology itself. Nuclear power was dangerous, but at least it's somewhat tricky to generate refined uranium. CRISPR, unfortunately, is theoretically not that tricky.

This may lead to ecosystem crashes, but almost certainly not extinction. The gene drive, here, relies on two major features: high reproductive rate of mosquitoes, and the maintenance of the elements responsible for the drive.

First of all, geographically or reproductively isolated populations will not be affected and will repopulate.

Second, the components of the drive may recombine, creating offspring that will not be affected by the drive, and will out-compete the affected individuals within two generations.

Needless to say, the number of mosquitoes (of this species) will plummet. Perhaps, other insects, including mosquito species, will take advantage of their absence. But given their ubiquity and population sizes, some will survive. Maybe the genetic bottleneck that occurs will make them more susceptible to disease, but that's minor.

If we're going to be making species extinct anyway, I don't see any reason not to make wiping out the harmful ones a priority. Can we do Toxodendron next?

Mosquitoes seem like they belong on the bottom of the moral weight spectrum, above viruses and below bacteria.

None of the concerns I've seen voiced are moral; they're mostly worries about unintended effects on the ecosystem.

But really, when has that ever happened before?

Unintended consequences of ecological interventions? All the time.

This needs to happen as soon as possible.

According to the WHO http://www.who.int/malaria/en/

There were 216 million malaria cases worldwide in 2016 with 445 000 deaths.

Developing nations, especially in Africa are most severely affected by this.

Whoever, manages to eradicate the mosquitoes surely deserves the Nobel prize in Medicine as well as the Nobel Peace Prize.

The number of deaths is true but not the whole truth. It was almost twice as high in the year 2000.

What could go wrong?

Well, it's worth asking. On the other hand, one rebuttal would go something like:

P1. We should calibrate our tolerance for risk against the level of harm we're addressing.

P2. Mosquitoes are at the high water mark for ongoing harm to humanity.

C. We should be more tolerant of risks here than against any or at least most other problems in the world.

Another rebuttal would be that a survey of leading biologists and entomologists leads to near unanimity that suddenly erasing mosquitoes from the planet wouldn't really have any downsides on the larger ecosystem:

https://www.wnycstudios.org/story/kill-em-all/ https://www.nature.com/news/2010/100721/full/466432a.html

To be fair, note that some rare arctic orchids might be affected: http://www.mosquitoreviews.com/mosquitoes-niche-pollinate.ht...

If you want an updated review of biocontrol more generally, Outside/In has a great episode about it, with interviews with proponents and critics of biocontrol. One takeaway might be that there are a bunch of overlooked success stories, and the widely popularized failures provide a really distorted sample: http://outsideinradio.org/shows/s02e01

On the other hand, it includes interviews with critics of biocontrol as well, so I feel like you could learn more details about both sides of the discussion.

Other contrarian stories about invasives: https://www.wired.com/2011/02/good-invasives/ https://news.nationalgeographic.com/news/2014/07/140724-inva... https://www.nytimes.com/2016/03/01/science/invasive-species....

If you want beautiful and complicated historical poetry about a human intervention that lead to a population collapse, The Memory Palace will take you back to the late 1800s: https://player.fm/series/the-memory-palace-110374/episode-13...

What about releasing a genetically altered strain of the malaria organism itself?

Crashing the mosquito population greatly diminishes transmission of the disease.

Because malaria mostly infects humans, if you managed to create a malaria that conferred immunity, you'd have to infect lots and lots of people with it to spread it into the wild, and then it would only infect a subset of the people with the normal malaria strain.

Maleria reproduces asexually, so I guess it wouldn't work.

Malaria reproduces both sexually and asexually depending on its lifecycle stage.

Immune mosquitoes would be good too, though certainly more challenging to engineer than "kill everything".

Is such an invasive method even needed? Malaria deaths are down by almost 50% in the period of 2000-2015 according to WHO data.

This solution isn't about reduction, it is about eradication.

It is cost effective and also implies that you can do other things along the same lines. For example, you could do the same thing to Aedes aegypti (another mosquito species that carries thinks like Zika and Yellow Fever). You might be able to do it to bot flies. Lone Star Ticks. Or many others.

While I would love to see tick-borne disease wiped out, I just don't think that wiping out ticks is the right way. Instead, how about wiping out the parasites that are borne by these ticks?

It's a never ending cascade of special eradication. Today, ticks and mosquitoes carrying life threatening agents. Tomorrow, perhaps rats, cats, mice, sparrows, bed bugs, termites, and any other organism that we find inconvenient? How about certain kinds of humans, perhaps we can terminate people that are cognitively impaired? Wielding the rod of genocide seems like a poor choice.

The difference is that while animals like mosquitoes have many offspring and are sexually reproducing, many of the microscopic parasites are not…

The gene drive requires sexual reproduction to spread and produce sterile mosquitoes.

Huh, maybe this will open an opportunity for sex-non-obligate mosquitoes infected by Wolbachia, if those are even produced by their interaction

Your answer sounds like "because we can".

You have to ask why they are down as well.

Bhatt et al. (2015)4 studied the decline of cases of malaria in Africa between 2000 and 2015. They found that the single most important contributor to the decline were insecticide-treated bed nets. According to their findings bed nets were responsible for the aversion of 68% of the 663 million averted cases in Africa between 2000 and 2015. These are 451 million averted cases.

Excerpt taken from https://ourworldindata.org/malaria#bed-nets .

Furthermore only 30% of the population is sleeping under a bed net already in sub-Saharan Africa as mentioned bit further down in the same article. So there's still room for improvements.

I think a more interesting question than "should we do this or not" is "how would you build a tool that could model an entire ecosystem?". Does anyone reading this know what scientists use to do this currently?

I did a little bit of this for my masters project. Modeled ecosystems and measurements of the ecosystem as partially observed markov processes.

Poor parts of Africa, Asia and Oceania are the ones who suffer and getting perpetually killed by this disease, not just malaria, even dengue, yellow fever, etc which have may have cause by mosquito. Why it keeps happening is that because they don't have really help from the Government about proper health care and education on how and what to do to avoid this. People, specially on poor status, mostly rely on their homemade or even herbal treatment that we knew will not help them at all. Malaria is a curable disease.

Just to play devils advocate.. what's the worst possible way this technology could be used? What if you give the mutation to people? Maybe people you don't like for some reason?

This will clearly have a negative, long-term effect on the environment by causing up to 400000 more human beings to reach sexual maturity in a part of the world where expanding human population is the major environmental threat. And, in the long run, a collapsing natural environment is also going to cause tremendous human suffering and death. But never mind it's just a drop in the ocean anyway, so go ahead.

Could they develop another version of the gene-drive modification that undoes the first effect? It seems like they should be able to do this and conduct an experiment in the laboratory that proves that there is at least theoretical ability to reverse the effect if it prove desirable to do so for some reason.

Seems like an achievable improvement on the safety model for this technique? Maybe a necessary step before deploying a tool like this for the first time?

This is theoretically possible. Researchers have also considered creating gene drives that automatically end after a certain number of generations.

It is a bit scary, but it is probably prudent to support such research, not only for interventions like this but as a possible countermeasure against biowarfare and bioterrorism using gene drives.

This article talks about controlling Anopheles gambiae but something similar already being done to control Aedes aegypti.

https://debug.com/

A notable difference is that Debug is using the sterile insect technique (SIT)[1], as opposed to gene drives, which are much harder to control once released. With SIT, 1) we have a lot more experience using it for decades, and 2) it's pretty easy to simply stop releasing sterile insects if unintended consequences were found.

[1] https://en.wikipedia.org/wiki/Sterile_insect_technique

> something similar already being done to control Aedes aegypti.

Which carry: yellow fever, dengue fever, Zika fever and chikungunya.

I think this should be released without any form of government or popular consent (i.e. don't even ask them); JFDI. We do so many worse things on a regular basis with more concrete known negatives for far lower benefits.

Well aren't we just a paragon of bad ethics.

First they came for the mosquitos...

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