The Fall and Rise of Screwworm

https://www.construction-physics.com/p/the-fall-and-rise-of-screwworm

by crescit_eundo • 19 days ago

153 62 19 days ago

goda902• 19 days ago

I wonder if anyone ever did the math on whether trying to maintain a barrier at the Darian Gap with occasional failures was really a better financial choice than teaming up with South American countries to drive screwworms to extinction.

AlotOfReading• 19 days ago

Yes, they did because various countries have talked to the US about expanding it. The problem is that South America is an enormous place, whereas Panama is a narrow isthmus. It could have been done with some amount of money, but that opportunity ended in 2010 at the latest.

cogman102• 19 days ago

[deleted for being misinformation]

moffkalast2• 19 days ago

In the end though, history will see it as a half measure where they really shouldn't have half assed it. It only took one moron to defund the project and all of it will come streaming back.

consensus13• 19 days ago

I think the issue is that you would have to push the barrier across the entire South American continent, which is twice the distance of the US-Mexico border and also crosses the Amazon where there is basically no infrastructure.

praptak• 19 days ago

Releasing the steriles blindly is not enough, you gotta monitor the pest too. This is prohibitively expensive in rainforests and other areas with poor infrastructure.

Okay, maybe you could release the flies in large enough numbers not to need monitoring but I guess it would also be prohibitively expensive.

nine_k2• 19 days ago

It sort of worked with malaria mosquitoes.

smegger001• 10 days ago

we could possibly use a gene drive to make males that would only produce male descendants in a handful of generation they would go extinct.

readthenotes1• 18 days ago

I wonder if anyone ever did the math on transiting hundreds of thousands of people through the previously impassable Darien Gap would have unintended consequences?

whalesalad• 19 days ago

Eventually capable of producing more than 200 million screwworm flies a week, the Mission factory was a grotesque marvel of insect-producing efficiency. Operating 24 hours a day, 365 days a year, it was, in essence, a 76,000-square-foot artificial wound. Trays full of meat, blood, and water, each one heated to the exact right temperature to stimulate screwworm growth, moved through the facility on a monorail system timed to the lifecycle of the screwworm.

Imagine working at the screwworm factory.

bee_rider• 19 days ago

I guess you’d probably have taken some solace in the fact that you didn’t have to live at the screwworm factory. Past tense, unfortunately, since the worms are setting up their own factories all over.

alexpotato• 19 days ago

I was born with no sense of smell [0] and I always wondered if I could combine that with my tech skills to be CTO at a place like the screwworm factory or possibly Waste Management.

0 - https://x.com/alexpotato/status/1559865770515087360?s=20

delichon• 19 days ago

I applied this principle and married someone with a great sense of smell

May you and your smelling nose wife live happily ever after.

trashface• 19 days ago

I'm sure the fly production methodology has improved over the years, but based on what TFA describes, I'm not sure lacking smell would save you from disgust. I think even a Buddhist would be hard-pressed to find compassion for this particular fly species.

computerdork• 19 days ago

Scenes from the human harvesting operations at in the Matrix come to mind, but am sure it's different than that:)

comrade1234• 19 days ago

Out of curiosity I looked up the cost to south American beef producers like Argentina/brazil. The extra constant animal inspections costs ~$10 per cattle up until slaughter I think. Not a huge cost but a pain nonetheless.

boelboel• 19 days ago

$10 in Brazil/Argentine would be significantly more in the US because of labour costs I assume. Is there any training needed for the inspections/enough people who could do it on a short notice in the US? Could drive up the price even more.

Not that I believe it'll drive up the price that much but I wouldn't be surprised if it ends up being 50-70 USD per in the US.

dcrazy• 19 days ago

Surely the bigger issue is not the inspections, but the loss of infected livestock?

marcosdumay• 19 days ago

It's not some contagious disease that will spread to every animal. One can just treat the infected cattle until they get healthy again.

CodingJeebus• 19 days ago

Overall, the screwworm program seems like a classic case of something becoming a victim of its own success: a problem got solved so thoroughly that we forget how big of a problem it was, and we gradually undermine the conditions that made the solution possible.

Chesterson's Fence strikes again. It's so easy to wax poetic about how ineffective government spending always is and should be cut to the bone that we don't stop to recognize that preventative programs like this save us from billions in economic losses.

JKCalhoun• 19 days ago

"Some anti-screwworm efforts may have been hindered by DOGE, which cut APHIS staff, screwworm monitoring programs, and may have delayed funding for the Mexico facility…"

Yep.

beloch• 19 days ago

There appears to be some controversy over whether DOGE's cuts directly caused this specific outbreak[1].

---

"Though it appeared DOGE did cancel funding to the FAO, which works to monitor and control outbreaks of screwworm, in 2025, it was not possible based on the available evidence to conclude that the canceled grant directly caused the outbreak in the U.S. or to determine how it might have affected the FAO's work to contain the parasite in Central America."

---

My interpretation would be that, as the parent article says, there were circumstances that have been leading to this outbreak for years. It may have happened even if Trump were never elected. However, one thing this article makes very clear is that screwworm control measures need to be in place across international borders. It takes efforts in Mexico and further South to stop screwworms before they reach the U.S.. Funding screwworm control in Mesoamerica is actually in the U.S.'s self-interest.

While this particular outbreak may have occurred anyways, cutting funding to screwworm control in Mexico and further South as a part of cutting foreign aid likely exacerbated the problem and will prolong the outbreak. The U.S., purely out of self-interest, should have been boosting funding to screwworm control South of their own borders in 2025, not slashing it.

--------------

[1]https://www.snopes.com/news/2026/06/12/doge-cuts-screwworm/

needSomeCoffee• 19 days ago

Thanks to the author. That was a great read imho. Loved the early parts about the guys who -- despite the ridicule and lack of resources -- achieved eradication. Again, great read.

taco_emoji• 19 days ago

Well that's nightmare fuel D:

Planktonne2• 19 days ago

(Some anti-screwworm efforts may have been hindered by DOGE, which cut APHIS staff, screwworm monitoring programs, and may have delayed funding for the Mexico facility, but it’s hard to be confident about this, and the administration has unsurprisingly rejected these claims.)

For an article that is so detailed in other areas, this feels like a very short dismissal of a topic that--regardless of direction--deserves more focus.

natbobc2• 19 days ago

DOGE probably didn’t help matters but the problem started to rise in 2023. My gut reaction was “damn that DOGE!” too but they didn’t start with cuts until 2025. So it likely just exasperated an already growing concern. This is the same kind of stuff anti-vaxers don’t get. We left South America out of the equation so when the circumstances of migration and feeding changed so did the status quo of a “screwworm free” line in the sand. Other peoples problems can quickly become everyone’s problem if left unchecked.

mrj• 19 days ago

That's worse though. Cutting a program that had been successful for decades is short sighted, but people tend to begin focusing on the cost of prevention after so long. Memories fade and the question starts to become, "Why are we still spending so much?"

That's not what happened. DOGE carelessly cut a program in the middle of fighting a crisis.

Planktonne2• 19 days ago

I'm not saying it was DOGE--the article introduces a host of other causes--but I think both DOGE and those other causes deserved a lot more airtime than they got; what caused the problem is relatively briefly handled, but what actually went wrong is a key part of the story.

srean3• 19 days ago

I have a question for folks who have background in interventions like these.

Isn't there a risk that the artificially introduced reproductory pressures would select for screwworms that produce males that are resistant to radiation.

My chain of reasoning is that not all the of the irradiated males would be completely sterile. If so, then the next generation would be a mix of hatchlings of not radiated parents and those parents who have not been completely sterilized in spite of radiation -- thereby increasing the proportion of radiation resistant varieties, assuming resistance is an inheritable trait. These may then find themselves at the input side of sterile male generation factories.

The intervention obviously worked, but was that because steps were taken to counteract the possibility of raising radiation resistant varieties.

BTW the article was a great read.

SoftTalker2• 19 days ago

I'm not sure radiation resistance is really a thing. Radiation causes physical damage, it's not like a virus or bacteria that an organism can potentially fight off with an immune response.

The few males that might survive the gamma exposure with intact fertility are probably just ones that didn't get a full dose.

It is rather amazing to me in fact that it's possible to sterilize the males without killing them.

goda902• 19 days ago

This might be a way to adapt to radiation: https://en.wikipedia.org/wiki/Radiosynthesis_(metabolism)

srean3• 19 days ago

Couldn't there be genes that help with repairing the radiation induced damage ?

From what I have read, flora and fauna around Chernobyl seems to have acquired degrees of radiation tolerance.

BTW I am a complete ignoramus in these matters.

AlexCoventry• 19 days ago

Surprisingly, it is a thing.

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

causality0• 19 days ago

Everything is a thing. Immune systems are, when all is said and done, physics. Simpler forms of death tend to be harder to evolve resistance against, but given enough generations it will happen. For example, microorganisms regularly evolve increasing resistance to sterilizing chemicals, such as enterococcus faecium evolving resistance to isopropanol, various species of bacillus increasing their resistance to hydrogen peroxide, pseudomonas evolving resistance to benzalkonium chloride, etc.

spacemanspiff01• 19 days ago

Not knowledgable, but irradiated flies should not be expected to be irradiated again. There are 3 population pools:

1. The Factory spawning population - This is self-sustained, and never encounters radiation.

2. A subset of the spawned males from the factory population are irradiated, making them sterile.

3. The wild population, consisting of the sterile males + wild males + wild females.

If for some reason the sterile population is not fully sterile (unlikely), then maybe there is a gene that helps for radiation resistance, but the children of that strain will not encounter radiation, so it fades away.

The factories are not going out to the regions where the flies are deployed to get new fly studs.

srean3• 19 days ago

Your 1. By itself would mitigate the risk I think.

jiggawatts• 19 days ago

There can be selection pressure for females to mate with multiple males.

Releasing sterile males only works for species that mate only once or at most twice, and rapidly falls off in effectiveness for species where the females mate many times.

raphinou• 19 days ago

I'd expect that if females start to breed more than once it would represent a problem. It's surprising it hasn't happened yet (for the ignorant of the field that I am at least)

Eric_WVGG2• 19 days ago

The Southwest Animal Health Research Foundation (SWAHRF), an organization formed by a small group of Texas livestock producers… broke the logjam by raising millions of dollars in voluntary donations from Texas ranchers for screwworm eradication.

That can’t be right. The Texas Department of Agriculture published a piece titled “Dollars Don’t Kill Screwworms” just two years ago.

https://texasagriculture.gov/News-Events/Article/10239/OPINI...

Listen, dollars don’t kill screwworms. Sterile flies do. Detection systems do. We already have the tools to manage this issue because we’ve been doing it successfully for decades.

See? We don't need big government programs to get this under control, we just need farmers to… I dunno… raise and breed their own own sterile flies, or buy them from Walmart.

Eric_WVGG2• 19 days ago

Fortunately, an even better location for a barrier existed: the Darien Gap, on the border of Colombia and Panama. At this narrow stretch of land, the barrier would need to be just 60 miles wide.

btw this is that terrifying jungle zone of Panama from the TV show Pluribus. Yes, it is real, and so are those trees.

- https://en.wikipedia.org/wiki/Darién_Gap - https://davesgarden.com/guides/articles/view/2904

dwroberts• 19 days ago

That Pigafetta palm is also pretty nasty, damn

they not only have very long, very sharp spines arming their leaves (see fallen leaf base on right), but they grow quickly to sixty feet tall or more, and then drop these deadly, spiny leaves, impaling whoever happens to be unlucky enough to be below at the time. These leaves can weigh over thirty pounds, too.

dang• 19 days ago

Recent and related:

Oh good, screwworms are back (2025) - https://news.ycombinator.com/item?id=48475898 - June 2026 (79 comments)

First U.S. screwworm case confirmed in South Texas - https://news.ycombinator.com/item?id=48397036 - June 2026 (34 comments)

mschuster912• 19 days ago

And when it was clear that screwworms had breached the barrier, responses were sometimes delayed by political disputes — Mexico apparently initially made it very difficult for USDA screwworm flights to operate until the US Agricultural Secretary called to force the issue.

DOGE aside, as the article and commenters already mentioned that - if that giant buffoon Trump wouldn't have gone and screwed up relations with virtually every country south of the US sans Argentinia and El Salvador, including invading Venezuela to oust their president, maaaaybe other countries wouldn't find the risk of screwworm more acceptable than risking American government flights over their countries.

The damage the two Trump administrations caused will take decades to repair. And frankly if I were a country south of the US - I'd invest in my own resources to combat screwworms. There simply is no guarantee that, even if Trump fails and someone sane is elected in two years, they won't elect someone just as braindead in six years.

consensus13• 19 days ago

You are blaming Trump for the failure of the Mexican government to act in its own self interest during the Biden administration?

mschuster912• 19 days ago

The Biden admin followed on the first Trump admin, member the "build the wall" crap?

Metacelsus• 19 days ago

Time to bring out the gene drives!

yread• 19 days ago

It sounds like the original research done 30s-50s would not be possible today. No one is getting an ethics approval for that. And "let me just get some cobalt-60" is probably also not happening

search_facility• 19 days ago

Current situation exist presisely due researches of 20th century though. This is largely connected things

SoftTalker2• 19 days ago

It's a bit odd that the screwworm exists. Normally a parasite that kills its host is at an evolutionary disadvantage.

I wonder if the human practice of keeping large groups of livestock together in close proximity creates an unnatural "target rich environment" for the flies that they don't otherwise experience, making them much more of a problem.

edoceo• 19 days ago

Can't we just compare this to "wild" population?

nine_k2• 19 days ago

Ungulates very often gather in large, close groups in nature, in order to defend themselves from predators, and to conserve heat during night time.

AndrewKemendo• 19 days ago

Wow the thing that stood out to me was the number of Darien Gap crossing not being zero.

I was under the impression that was the most dangerous part of the planet for every possible reason.

The fact that it’s half a million a year is crazy!

Something must have changed in infrastructure for that to even be possible right?

troglodytetrain• 19 days ago

Government solve problem. Problem gone. No more problem ever.

Problem come back? Because problem complex problem based on a large number of interdependent variables as is common is real life ecosystems? No way.

-Brought to you by grug gpt.

The Fall and Rise of Screwworm

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