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.
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.
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)
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.
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.
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.
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.
Hmm, that seems to contradict the article directly - insecticides were used to try to battle screwworm initially and were not really effective - the solution was using sterile male flies to stop reproduction - which would work in South America just as well as it did in North (with sufficient scale)
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.
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.
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.
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.
$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.
> 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.
> 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.
> 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.
> 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.
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.
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.
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.
> 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.
"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…"
The article is very clear that the issue arose in 2021 and the main causes are increased migration / cattle smuggling across the Darien Gap and over zealous COVID lockdowns. But sure, cherry pick that quote because you want to blame something that happened 4 years after the problem started.
> The article is very clear that the issue arose in 2021
“Sometime around 2023, the barrier at Panama failed”
And further text suggesting a fairly normal incursion in ‘21 that didn’t become a major issue until much later.
> and over zealous COVID lockdowns
“The disruption caused by COVID-19 seems to be partly to blame”
I love when people insert hyper-inflammatory bullshit because they have a stupid axe to grind.
There are like, 10 paragraphs of equally relevant contributors, but you picked out the two that make you angry and are pretending those are the “main causes”?
> during the pandemic livestock inspectors were forced to stay home, vehicles broke down and couldn’t be repaired due to a lack of replacement parts
You can be pedantic about the exact start time, but the initial outbreak was detected in 2021, the barrier breach became clear in 2022 and was widely spread by 2023. In any case this had nothing whatsoever to do with budget cuts in 2025.
> (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.
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.
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.
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.
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)
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.
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.
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)
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.
This might be a way to adapt to radiation: https://en.wikipedia.org/wiki/Radiosynthesis_(metabolism)
Coincidence ! Just mentioned about Chernobyl in a previous comment.
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.
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.
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.
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.
[deleted for being misinformation]
Hmm, that seems to contradict the article directly - insecticides were used to try to battle screwworm initially and were not really effective - the solution was using sterile male flies to stop reproduction - which would work in South America just as well as it did in North (with sufficient scale)
You and the article are correct so I erased my comment.
I found and read through some of the reports of the time to try and prove myself correct. I'm wrong.
https://www.nal.usda.gov/exhibits/speccoll/exhibits/show/sto...
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.
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.
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.
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.
$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.
Surely the bigger issue is not the inspections, but the loss of infected livestock?
It's not some contagious disease that will spread to every animal. One can just treat the infected cattle until they get healthy again.
> 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.
> 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
> 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.
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
> I applied this principle and married someone with a great sense of smell
May you and your smelling nose wife live happily ever after.
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.
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.
Scenes from the human harvesting operations at in the Matrix come to mind, but am sure it's different than that:)
> 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.
"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.
The article is very clear that the issue arose in 2021 and the main causes are increased migration / cattle smuggling across the Darien Gap and over zealous COVID lockdowns. But sure, cherry pick that quote because you want to blame something that happened 4 years after the problem started.
> The article is very clear that the issue arose in 2021
“Sometime around 2023, the barrier at Panama failed”
And further text suggesting a fairly normal incursion in ‘21 that didn’t become a major issue until much later.
> and over zealous COVID lockdowns
“The disruption caused by COVID-19 seems to be partly to blame”
I love when people insert hyper-inflammatory bullshit because they have a stupid axe to grind.
There are like, 10 paragraphs of equally relevant contributors, but you picked out the two that make you angry and are pretending those are the “main causes”?
Come the fuck on.
Doing it again:
> during the pandemic livestock inspectors were forced to stay home, vehicles broke down and couldn’t be repaired due to a lack of replacement parts
You can be pedantic about the exact start time, but the initial outbreak was detected in 2021, the barrier breach became clear in 2022 and was widely spread by 2023. In any case this had nothing whatsoever to do with budget cuts in 2025.
Well that's nightmare fuel D:
> (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.
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.
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.
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.