Speaker 1: One screw worm infestation that goes unreported could erase the
Speaker 1: tremendous gains that have been made in the Southwest against
Speaker 1: this insidious, multimillion dollar pest. The screw worm eradication workers
Speaker 1: can protect the gains, but only if they know where
Speaker 1: the pest strikes. You can help. Stopping screw worms is
Speaker 1: your concern, especially if you own livestock or a dog
Speaker 1: or cat or any other pet. All of you can
Speaker 1: help by finding and reporting screw worm infestations. Examine your
Speaker 1: animals at every opportunity. Look for cuts, scratches, or other wounds.
Speaker 1: If you find a wound that contains insect eggs or lobby,
Speaker 1: take about a dozen worms and all eggs from the wound.
Speaker 1: After you've taken the samples, treat the womb with approved insecticides.
Speaker 1: Place the samples in a container or jar in alcohol
Speaker 1: or water. At this point, speed is important. Call your
Speaker 1: county agent. He'll tell you where to send the samples.
Speaker 1: He'll tell you what action to take. Positive identification will
Speaker 1: be made by experts and measures taken to eliminate the parasite.
Speaker 1: A screworm infestation confirmed by positive identification sets off a
Speaker 1: series of emergency activities at schuwirm Eradication Headquarters, Admission, Texas. Here,
Speaker 1: millions of screworm flies are being read each day and
Speaker 1: made sexually sterile by exposure to gamma rays from radioactive cobalt.
Speaker 1: Released in special patterns and in large numbers, these laboratory
Speaker 1: reared flies fight for us against an outbreak. These sterol
Speaker 1: screworm flies mate with native flies, which in turn cannot reproduce.
Speaker 1: Release of steril flies, combined with intensive livestock inspection and
Speaker 1: use of insecticidal treatments, has already stemmed outbreaks. This new
Speaker 1: technique for insect control is eliminating screw worms from the Southwest.
Speaker 1: Complete success depends on quick discovery, quick reporting, quick action. Remember, examine, collect, treat,
Speaker 1: call you a county agent, and help stop schoolworms.
Speaker 2: That's the whole episode, is it not.
Speaker 3: Isn't that amazing?
Speaker 2: It's so comprehensive.
Speaker 3: It's so comprehensive. I okay, So that was from I
Speaker 3: found that on the USDA National Agricultural Library and like
Speaker 3: the screw worm exhibit, and it was a video produced
Speaker 3: in nineteen sixty three and it's called Lookout for screw Worms,
Speaker 3: and I just it was I think I didn't realize
Speaker 3: the extent to which screwworm was such a big deal
Speaker 3: during that time period for decades and decades and decades,
Speaker 3: enough so that there are like promotional videos like this, right, Okay.
Speaker 2: I'm really excited, Aaron to hear you talk about the
Speaker 2: history because I was reading and didn't realize like a
Speaker 2: lot of the history of like ranching the US was
Speaker 2: driven by screwworm.
Speaker 3: Yeah, I know, I know, And it's so funny. Yeah,
Speaker 3: I mean, there's there's so much to cover. We'll get
Speaker 3: into it. Okay, I want to start right now, but
Speaker 3: I want you to we'll start instead with introductions. Hi,
Speaker 3: I'm Aaron Welsh.
Speaker 2: And I'm Erin Almann.
Speaker 1: Update.
Speaker 3: This is this podcast will kill You.
Speaker 2: And today we're talking about screw worms.
Speaker 3: Shrew worms specifically for me, I'm talking about New World screwworm.
Speaker 2: Yeah. Well, we'll go over both different types of screwworms,
Speaker 2: new World and Old World, but realistically we're mostly talking
Speaker 2: about New World screwworm.
Speaker 3: Today, the one that's been in the headlines, in the news,
Speaker 3: spend in the news big time. It's gonna be a
Speaker 3: really interesting episode and a little bit maybe creepy Crawley
Speaker 3: as told to me A little bit, a very very
Speaker 3: creepy crawling. Yeah. Some of the descriptions I have are
Speaker 3: hard to stomach.
Speaker 2: Okay, that's good. I don't have that many of those.
Speaker 3: Okay, okay, I'm keeping it basic. But before we get
Speaker 3: into all of that, it is quarantine quarantiny time. Yeah,
Speaker 3: what are we drinking this week?
Speaker 2: We're drinking there's creworm driver. Yeah, it was just a screwdriver.
Speaker 3: Screwdriver which is, you know, vodka and orange juice, and
Speaker 3: with the addition of a gummy worm.
Speaker 2: Gummy worm to represent screw worm. We're getting real creative
Speaker 2: with these erin you know. I think that's okay, It's
Speaker 2: totally fine. Okay, it has to be. It has to be.
Speaker 2: We can do nothing else.
Speaker 3: Yeah, yeah, yeah.
Speaker 2: We'll post on the places that you can find it,
Speaker 2: like our website. This podcast will kill you dot com someday,
Speaker 2: but also definitely on our socials. This podcast will kill
Speaker 2: you what socials?
Speaker 3: Oh I have I try to post one. I don't
Speaker 3: know if it works very well. I can't figure out
Speaker 3: the dimensions, but hey, we're working on it. There's no
Speaker 3: way to do.
Speaker 2: Listen, there's a way. There's a lot of other great
Speaker 2: stuff on our website.
Speaker 3: Yes, there is. If we've got transcripts, We've got references
Speaker 3: for all of our episodes, so if you want to
Speaker 3: read more about screwworm, that's a great place to go.
Speaker 3: We've got links to merch to our bookshop dot org
Speaker 3: affiliate account, to our Goodreads list, to music by Bloodmobile,
Speaker 3: contact us, form a, submit your first hand account, form Patreon,
Speaker 3: other things. Probably check it out.
Speaker 2: There's a lot there. Yes, podcastwikill you dot com. If
Speaker 2: you haven't yet radio reviewed and subscribe, please do that.
Speaker 2: We'd really love it. We're on YouTube on the exactly
Speaker 2: Right network channel, and we're on all of your favorite
Speaker 2: podcasters including iHeartRadio, Apple Podcasts, Spotify, the like, the moving on,
Speaker 2: moving on?
Speaker 3: Are we done? Should we be great?
Speaker 2: You ready?
Speaker 4: Yeah?
Speaker 3: I am.
Speaker 2: I'm going to tell you about the biology of screwworm
Speaker 2: really fast, so that you can tell me about the history.
Speaker 3: Okay, okay, let's take a quick break and then we'll
Speaker 3: get to it.
Speaker 2: The star of today's show is the screw worm, which
Speaker 2: is a larval form of a fly. Most people, when
Speaker 2: we say screwworm mean the New World screwworm, which is
Speaker 2: the species Cochlio maya Homnivorax. Might have pronounced that wrong, hominivoras. Listen,
Speaker 2: it's the New World screwworm. But there is another one,
Speaker 2: the Old World screwworm, which is a species called Chrysoma besiana. Okay,
Speaker 2: and these are two different genera of fly, but both
Speaker 2: of them are blowflies overall not entirely dissimilar to the
Speaker 2: flies whose larval forms not that long ago an episode
Speaker 2: we hailed for the benefits of their ability to help
Speaker 2: heal wounds.
Speaker 3: Yeah, this may change our feelings on maggots.
Speaker 2: I think it will, because today we're talking about pretty
Speaker 2: much the exact opposite. Unlike most other species of blowfly,
Speaker 2: the New World and the Old World, screw worms larval
Speaker 2: forms feed not on necrotic or dead tissue, but instead
Speaker 2: on the warm and living tissue of warm blooded animals. Yeah. So,
Speaker 2: screwworms are a type of fly who lay their eggs
Speaker 2: in the flesh of living mammals in a way that
Speaker 2: causes really significant harm.
Speaker 3: Kind of like botflies, but more harmful, way more harmful.
Speaker 2: That So, what I want to do in this part
Speaker 2: of the episode is really just kind of take us through,
Speaker 2: like what are these flies? What do their life cycles
Speaker 2: look like? And why do they cause as much damage
Speaker 2: as they cause? So that you can tell us about
Speaker 2: all of the history with them, because I know it's
Speaker 2: really interesting. So adult flies of these both of these species,
Speaker 2: they look fairly similar. Most of what I'm going to
Speaker 2: talk about is about Cochliomaya, Hominivorax or the New World
Speaker 2: screw worm, but it mostly all applies to the Old
Speaker 2: World screwworm as well. They look a tiny bit different,
Speaker 2: but otherwise they're really quite similar.
Speaker 3: I'm so interested in their evolutionary history, which I didn't
Speaker 3: look up, like the relationship between them, was it like independent?
Speaker 5: Yeah?
Speaker 2: Anyway, Like oh, I didn't look at it either, but
Speaker 2: that's really interesting, Like yeah, how they both end up
Speaker 2: evolving this way of life that's so different from all
Speaker 2: of their other brethren, right.
Speaker 3: I mean it's a it's a great you know open
Speaker 3: niche I guess, like, yeah, someone else has got all
Speaker 3: the dead ones. You can get the live ones right
Speaker 3: exactly anyway.
Speaker 2: And so the adult flies, all entomologists everywhere are going
Speaker 2: to kill me for saying this. They look like a fly, Okay,
Speaker 2: how big, a little bit larger than a horse housefly. Okay,
Speaker 2: not a horsefly, housefly. And that's literally what they look
Speaker 2: like because they are blowflies. A lot of the houseflies
Speaker 2: that we see not houseflies, aren't necessarily blowflies. But you
Speaker 2: see these around. They've got almost like a metallic ish
Speaker 2: kind of bluish greenish body like most blowflies do. They
Speaker 2: have these big, giant orangish eyes across their heads, and
Speaker 2: then they have these three black and gray stripes along
Speaker 2: their back. The Old World screw worm has two of
Speaker 2: those stripes.
Speaker 3: Okay.
Speaker 2: The New World screw worms are native to essentially the
Speaker 2: entirety of the Americas, though they are primarily a tropical species.
Speaker 2: They need warm, moist soils in order to complete their
Speaker 2: life cycle, which goes something like this. The adult flies
Speaker 2: emerge from the soil where they pew paint, and it
Speaker 2: is only the adult females, As is usual for flies
Speaker 2: who cause the majority of the problems, they mate just
Speaker 2: one time. This is important, usually around day three to
Speaker 2: five of life, and then they start laying eggs right
Speaker 2: around that time day five to seven, after they come
Speaker 2: out of their people form, these flies lay two hundred
Speaker 2: to three hundred eggs. Some estimates say as much as
Speaker 2: five hundred eggs per clutch. It keeps getting worse, yep,
Speaker 2: because they lay additional clutches every three to seven days,
Speaker 2: for up to eleven clutches of two to three hundred
Speaker 2: eggs in a lifetime. And we can air in mathis
Speaker 2: though we don't have to because it's all over the papers.
Speaker 2: They lay a maximum of three thousand eggs per single
Speaker 2: female screwworm fly throughout the course of their twenty plus
Speaker 2: day adult life.
Speaker 3: I mean that is some hard work, it really is.
Speaker 2: They also often leave each one of their clutches in
Speaker 2: like several different egg masses, so not all like two
Speaker 2: hundred and one spot. They'll lay them like over of
Speaker 2: course of a few minutes or a couple of hours,
Speaker 2: in multiple times.
Speaker 3: Right, don't put all your eggs in one lesion. Kind
Speaker 3: of a mentality, exactly exactly, And they do. They lay
Speaker 3: their eggs in lesions on the margins of wounds on
Speaker 3: warm blooded animals, mammals, possibly birds, though they don't tend
Speaker 3: to prefer birds, but they can but all mammals, and
Speaker 3: they tend to prefer the kind of drier margins of
Speaker 3: fresh or bloody wounds compared to wounds that are severely
Speaker 3: infected or really wet or have a lot of like
Speaker 3: bacterial purulence. They want the freshest of flesh.
Speaker 2: The freshest of flesh, and they especially prefer wounds that
Speaker 2: have already been infested with screwworms, kind of like a
Speaker 2: signal that gets sent out like, hey, this is a
Speaker 2: really great wound, go ahead and lay your eggs here. However,
Speaker 2: they can also lay their eggs on other easily accessible
Speaker 2: parts of our like thin skin or mucous membranes, so say,
Speaker 2: the corners of eyes, or in noses yep, or near
Speaker 2: the perineum, or especially in places like insaane newborn mammals
Speaker 2: like newborn cattle or goats or horses that have an
Speaker 2: umbilical you know, stump that's not fully healed. That's a
Speaker 2: really common spot.
Speaker 3: Yeah.
Speaker 2: And then after a day or so, these eggs hatch
Speaker 2: into hundreds of maggots, the larval form of a fly,
Speaker 2: and these maggots eat their way in around and under
Speaker 2: the skin of their host, literally bear trying themselves in
Speaker 2: the process, which is how they get their name screwworm.
Speaker 2: Their wriggly little maggot bodies are even grosser looking than
Speaker 2: most maggots they have. It's not a thing.
Speaker 3: I mean that is a high bar. Maggots are disgusting looking.
Speaker 2: Maggots are gross looking. But these ones have particularly sharp
Speaker 2: hooks eyes of their mouthpieces, and their bodies have these
Speaker 2: sets of rings that kind of point backwards of these spines,
Speaker 2: these rings of like you know, like the kind of
Speaker 2: spines where like you can drive over them, but don't
Speaker 2: drive backwards.
Speaker 3: Yep.
Speaker 2: Yeah, and that is what helps them literally cork screw
Speaker 2: their way deep into the living tissues on which they're feeding.
Speaker 3: How big do these larvae get?
Speaker 2: Oh, that's a really good question. I actually didn't see
Speaker 2: anything about the particular sizes. I mean, they're not large.
Speaker 2: They're small individually, maybe a few millimeters big. Okay, okay,
Speaker 2: can Yeah. They feed for about a week before dropping
Speaker 2: off to pupate in the soil for another week, and
Speaker 2: then they'll emerge as adult flies.
Speaker 3: And once they emerge, okay, so I'm thinking about like
Speaker 3: going to in a place where screwworm is present. How
Speaker 3: many you said that the females only mate once, and
Speaker 3: so how many rounds of females in a year is happening,
Speaker 3: you know what I mean, Like, right, it's not like idea,
Speaker 3: it's like one week then do they overwinter, et cetera,
Speaker 3: that kind of thing.
Speaker 5: Yeah.
Speaker 2: So, I mean they tend to live in the tropics,
Speaker 2: and in the tropics, they're there all year round, right,
Speaker 2: and so they're going to be continually in each female.
Speaker 2: Adult females live for about twenty ish days, ok And
Speaker 2: then you know they're going to lay their eggs starting
Speaker 2: on day like four or five, and the eggs only
Speaker 2: take about a day before they hatch, and then they
Speaker 2: feed as larvae for about a week and then they
Speaker 2: pew paint for about a week. And so their whole
Speaker 2: life cycle is maybe what's that like a month a
Speaker 2: little more than a month, Okay, And so you could
Speaker 2: be getting twelve plus rounds, I mean, plus each female
Speaker 2: is laying like three thousands. Yeah, I can't even calculate.
Speaker 2: That's a lot.
Speaker 3: It's just hard to comprehend. Like like they I feel
Speaker 3: like they would run out of living tissue to eat.
Speaker 2: It's an interesting So it's actually really interesting that you
Speaker 2: say that because one of the one of the papers
Speaker 2: that I read was looking at like the overposition behavior
Speaker 2: of these flies, and they were pointing out that, like
Speaker 2: if you look at the way that they overpause it,
Speaker 2: and like how frequently they do it, and how they
Speaker 2: lay their eggs in these like multiple different clutches and
Speaker 2: all of this, but they do it multiple times in
Speaker 2: their life, right, Like a lot of a lot of
Speaker 2: flies or other insects might just lay like one giant
Speaker 2: clutch and then go ahead and die. But the way
Speaker 2: that these particular screwf lines do it, they at least
Speaker 2: in this paper, were saying that this fits with this
Speaker 2: strategy of like exploitation where they might be evolutionarily finding
Speaker 2: niches that aren't always there, right in an environment that's
Speaker 2: not always favorable. And so you've got to be able
Speaker 2: to take advantage lay a whole bunch of eggs as
Speaker 2: soon as you can and as quickly as possible when
Speaker 2: you find the right wound, because you don't know when
Speaker 2: you will again, which suggests that in nature, the perfect
Speaker 2: wound over position site might have been harder to come by.
Speaker 2: But then enter live stock livestock. Yeah, and now there's
Speaker 2: basically free terrain. Because when I before I started researching this,
Speaker 2: and when I thought of like the wounds that screw
Speaker 2: worms were causing, but also that they were first laying
Speaker 2: their eggs in. I always thought of like a huge,
Speaker 2: gaping like wound, right, like some kind of large hole,
Speaker 2: some infected something. But actually that's not the right image
Speaker 2: to have. The types of wounds that these flies can
Speaker 2: overpose it in to begin with, can be as small
Speaker 2: as a tick bite.
Speaker 3: And often are from a tick bite exactly.
Speaker 2: And so it's any break in the skin, a scratch
Speaker 2: from a thorn or a fence wire, like I said,
Speaker 2: the belly buttons of newborn animals insect bites. The wounds
Speaker 2: that can then be caused are incredibly substantial, and animals,
Speaker 2: especially livestock animals, can die within a number of days
Speaker 2: to weeks after infestation with a screwworm or it's multiple screwworms,
Speaker 2: because of how deeply these screwworms can wander and destroy
Speaker 2: tissue along their way, and because of things like secondary
Speaker 2: bacterial infections that can occur from you know, just the
Speaker 2: open wound that is caused by these maggots. So that's
Speaker 2: that's like mostly screwworms arin.
Speaker 3: And Okay, so between the Old World and New World,
Speaker 3: are there differences in the severity or in the number
Speaker 3: of eggs, or you know, whatever it is.
Speaker 2: It's a good question. It was like weirdly hard to
Speaker 2: find great papers on the Old World screwworms. So from
Speaker 2: what I can tell, they they don't tend to be
Speaker 2: maybe quite as severe or at least not as deadly
Speaker 2: as quickly. Okay, Okay, I don't I don't know exactly why,
Speaker 2: Like what are you know, all of the specific differences
Speaker 2: between them, As I know you'll probably talk about, the
Speaker 2: biggest difference in how we've dealt with them is that
Speaker 2: there are not as many programs that are widespread to
Speaker 2: try and eliminate the old world screwworms. So it is
Speaker 2: very much still a problem throughout its distribution. I see,
Speaker 2: whereas we have changed the current distribution of the New
Speaker 2: world screwworm.
Speaker 3: Yeah against us you will.
Speaker 2: Yeah. And then in terms of like how do we
Speaker 2: manage it? Aside from what you're about to talk about,
Speaker 2: I just keep like putting little putting, little teasers out there.
Speaker 2: We don't have any kind of vaccine, we don't have
Speaker 2: any kind of like specific treatment for screwworms. It's basically
Speaker 2: when we're talking about livestock insecticides on the wounds or
Speaker 2: like insecticide dips and things to try and help prevent
Speaker 2: the screw worms infection to begin with, we can also
Speaker 2: use avermectins like ivermectin, so for humans with when there
Speaker 2: is human infection, because there can be, and there there is.
Speaker 2: This is also a public health problem, not just a
Speaker 2: livestock problem. Yep. It requires oral ivermectin. And this doesn't
Speaker 2: like get rid get rid of the infection per se.
Speaker 2: What it does is paralyze the larvae, which then have
Speaker 2: to still be removed thereafter.
Speaker 3: Okay, it paralyzes the larvaie how interesting? Yeah?
Speaker 2: Yeah, So our main stay of dealing with the New
Speaker 2: World screwworm has been sterile insect technique.
Speaker 3: It's so cool prevention.
Speaker 2: Tell me all about it?
Speaker 1: Is it?
Speaker 3: Really?
Speaker 2: Yeah? I don't have any more great. Is going to
Speaker 2: be basic and straightforward.
Speaker 3: I'm excited. All right, let's let's get started. So to
Speaker 3: help me set the stage for the history of screwworm,
Speaker 3: I've brought along some assistance. Aaron.
Speaker 2: I can't wait.
Speaker 3: Please open the video titled screw Worm one.
Speaker 5: Three hundred million years before man appeared on Earth, the
Speaker 5: insect was here with time to develop varieties so diverse.
Speaker 5: Their numbers are beyond conception, roughly a million species along
Speaker 5: with ticks and mites, three fourths of all the animal kingdom.
Speaker 5: Of these ten thousand species are man's mortal fol endlessly
Speaker 5: vying with him for food and fiber, endlessly looting what
Speaker 5: he has sown and ended.
Speaker 2: Did you like that? I loved it, Aaron. I really
Speaker 2: hated the grub Those were grubs, not maggots.
Speaker 3: Listen, the video is like everything grubs country.
Speaker 2: Yeah, that was clear.
Speaker 3: It's so fun so that I loved it so much.
Speaker 3: That video is from It was produced by the US
Speaker 3: Department of Agriculture, the usd DA in nineteen sixty nine,
Speaker 3: and it goes into some of the various like insect
Speaker 3: and plant pests screwworm that I've been plaguing farmers across
Speaker 3: the globe. I also thought it was interesting because it
Speaker 3: was like one million species, and I looked it up
Speaker 3: and I think we're now at like five point five
Speaker 3: million species. One million is such an underestimate, right, It's
Speaker 3: like doctor Evil, like one million dollars. Like that's kind
Speaker 3: of what it reminded me.
Speaker 1: See.
Speaker 3: Yeah, but Yeah, I went all in on video clips
Speaker 3: for this episode you're about to find out. So, Yeah,
Speaker 3: there's an amazing archive work at the National Agricultural Library
Speaker 3: on the USDA website and as well as the Internet archive,
Speaker 3: which is just one of my favorite things in existence.
Speaker 3: But but I wanted to start the history of screw
Speaker 3: worm with that clip because I feel like it transports
Speaker 3: us back to a time when New World screw worm
Speaker 3: was among the top threats to agriculture here in the US.
Speaker 3: And by the way, I'm going to just be focusing
Speaker 3: pretty much only on New World screw worm for this
Speaker 3: which I'm just calling screwworm for short.
Speaker 2: That's what most of the literature does. It's fite. It
Speaker 2: was hard for me to find stuff on old world
Speaker 2: screw worm.
Speaker 3: Yeah, but it's eradication from North and Central America in
Speaker 3: nineteen ninety one, which spoilers it was eradicated and spoilers
Speaker 3: it's back. It marked a tremendous achievement in pest control
Speaker 3: and a demonstration of what was possible without the use
Speaker 3: of toxic pesticides. It was a big deal. Hence the
Speaker 3: sheer volume of material that's out there about the screw
Speaker 3: worm eradication program, and after it was eradicated, it dropped
Speaker 3: out of the news cycle for the most part, except,
Speaker 3: of course, in the places where it was still prevalent,
Speaker 3: like most of South America, and the recent headlines about
Speaker 3: the reemergence of screwworm here in the US that might
Speaker 3: be the first time that many people have learned about
Speaker 3: or heard of this parasite, but in fact, it has
Speaker 3: plagued wildlife, humans, livestock in the Western Hemisphere for thousands
Speaker 3: of years, and so using genetic analyses, researchers recreated the
Speaker 3: historical spread of this parasite and found that it seemed
Speaker 3: to follow human migration throughout the Americas, suggesting yeah, as
Speaker 3: human migration continued across North America and then down into
Speaker 3: Central and South America, the screw worm followed them. And
Speaker 3: then the introduction of European livestock starting in the fifteen hundreds,
Speaker 3: of course, provided even more hosts and wherever it went,
Speaker 3: as long as it found a host on which to feed,
Speaker 3: and it wasn't too picky, It'll pretty much feed on
Speaker 3: anything that has living flesh and with suitable yeah yeah yeah,
Speaker 3: warm flush, warm flush, yeah, and with suitable climate conditions,
Speaker 3: it would just do its horrific thing wherever it could.
Speaker 3: And so last season we talked about how we did
Speaker 3: this episode on medicinal maggots and raved about how cool
Speaker 3: they are, which is so true. But the maiasis from
Speaker 3: screw worms is another matter entirely.
Speaker 2: It's not the same.
Speaker 3: It is not the same. I found a quote from
Speaker 3: ce Scruggs from nineteen seventy five that I think pretty
Speaker 3: much sums it up for me. Quote, it is doubtful
Speaker 3: that the mind of man could create a more vile
Speaker 3: scene than that of worms consuming the live flesh of
Speaker 3: one's body. The imagination almost refuses, particularly in this day
Speaker 3: and age, to conjure up the horrendous pain and outright
Speaker 3: revulsion that must come to a person infested with a writhing,
Speaker 3: seething mass of worms steadily tearing and consuming his flesh.
Speaker 2: End quote.
Speaker 3: It's I mean, it's truly awful. It is truly awful.
Speaker 4: Yeah.
Speaker 3: Yeah, And this feeling, this image, the sentiment towards myasis.
Speaker 3: This might have been what the guy who first described
Speaker 3: the New World screw worm was thinking when he gave
Speaker 3: it the name. The species name of haminivorax, which is
Speaker 3: man eater what it translates to. And so the guy
Speaker 3: who did this was named Charles Cockrell. He was a
Speaker 3: surgeon in the French Navy stationed at a penal colony
Speaker 3: Cayenne in French Guiana in the mid nineteenth century. Conditions
Speaker 3: at this penal colony were so awful apparently that it
Speaker 3: was given the name Devil's Island. And while he was there,
Speaker 3: he treated five men who were suffering from screw worm infestation.
Speaker 3: Flies had laid eggs in each of their nostrils and
Speaker 3: masses of larvae developed in their nasal sinuses, consuming the
Speaker 3: surrounding tissue. I know three of the five men died
Speaker 3: as a result of these infestations, and apparently three hundred
Speaker 3: larvae were recovered after rinsing the sinuses out with water.
Speaker 5: Yeah.
Speaker 2: Yeah, these ol passages seemed to be a really commonplace
Speaker 2: and there's human infestation.
Speaker 3: That it makes sense. You just can't get at it easily.
Speaker 4: Yeah.
Speaker 2: Well, and a lot of times too, there's there's there's
Speaker 2: something else going on, like you like you're in a
Speaker 2: place where you don't have access to be able to
Speaker 2: move around or clean your surroundings or whatever, or that
Speaker 2: you're sick with something else, so you're not able to
Speaker 2: like swat flies away. That's that sort of a thing.
Speaker 3: But it's still it's it's truly, it is truly awful.
Speaker 3: And I think that Cokeral himself was quite a bit
Speaker 3: taken back by what he saw, and he wrote in
Speaker 3: this description of treating these men that science is quote
Speaker 3: powerless to prevent these terrible ravages, and in that he
Speaker 3: would ultimately be proven wrong, but it would take another
Speaker 3: hundred years or so for science to have a fighting chance,
Speaker 3: and in the meantime, screwworm continued its path of destruction.
Speaker 3: In the second half of the eighteen hundred's cattle ranching
Speaker 3: banded greatly across the southwest US, especially Texas, and millions
Speaker 3: of acres were transformed by grazing, and also four grazing
Speaker 3: windmills were built to bring water to the surface for
Speaker 3: water holes. Screwworm flies like water, so that was one,
Speaker 3: you know, helping helping it along. Overgrazing meant fewer prairie fires,
Speaker 3: so more continuously occupied habitat, more continuous host for the
Speaker 3: screw worm, and deer replaced antelope as the dominant game animal,
Speaker 3: which grew even more abundant, so like deer herds, of course,
Speaker 3: are like can be enormous, so that's like even more
Speaker 3: hosts for the flies. According to one researcher's observation from
Speaker 3: nineteen fifty nine, deer are often victim to repeat infestations,
Speaker 3: leading to two to three thousand larvae in one wound.
Speaker 3: Oh goodness, and that amount of maggots of two to
Speaker 3: three thousand can destroy an area apparently seven inches wide
Speaker 3: and seven inches deep or eighteen centimeters wide and deep.
Speaker 2: Seven inches on a deer's body. Can you go seven
Speaker 2: inches deep without hitting some vital structure?
Speaker 3: Yeah, I guess you. That's you can't. Yeah, yeah, I
Speaker 3: mean wound wounds like these are can be deadly or
Speaker 3: often deadly, and in bad years, up to eighty percent
Speaker 3: of fawnds of white tailed deer were killed from these infestations.
Speaker 3: Oh yeah, and these deer also provided ample hosts for ticks,
Speaker 3: specifically the Gulf Coast tick or Amblio mammaculatum, which prefers
Speaker 3: to feed on the ears of livestock, and as we know,
Speaker 3: screworoms can lay their eggs in any wound, including tick
Speaker 3: bites and cow's ears are often a casualty. You can
Speaker 3: tell is this a screwroom infested area because all of
Speaker 3: their ears are just like gone or shriveled or yeah,
Speaker 3: partially torn. And apparently up to ninety percent of some
Speaker 3: of screworom lesions start from a tick bite in some
Speaker 3: areas where the tick is especially prevalent, and then others
Speaker 3: through common farming practices like castration, branding, dehorning, and then
Speaker 3: like you mentioned, newborn livestock are often affected at the navel.
Speaker 3: And on top of that, so we've got all these
Speaker 3: things going on right, Like, we've got more cattle, we've
Speaker 3: got water, we've got deer, we've got fewer prairie friers.
Speaker 3: This is all happening. And then you've also got the
Speaker 3: demand for beef skyrocketing since the development of refrigeration allows
Speaker 3: you to ship the meat that you don't sell locally,
Speaker 3: which previously had restricted herd size. And so now you've
Speaker 3: got the opportunity to create these massive herds because you
Speaker 3: can ship ship.
Speaker 2: It the meat. Oh wow, Aaron.
Speaker 3: Put it all together, and what you have are the
Speaker 3: perfect conditions for a screw worm storm. Just take over,
Speaker 3: just absolute takeover. And this parasite truly plagued the areas
Speaker 3: where they were established, and it was a horror for
Speaker 3: livestock owners. Quote this is a quote from one of
Speaker 3: these owners. Particularly disgusting and sickening job was when cows
Speaker 3: or calves got screw worms in their mouth and gums.
Speaker 3: This came about in two ways. One, the cow or calf,
Speaker 3: if they could reach the wound, would try to lick
Speaker 3: the worms out of the lesion. Thus some live worms
Speaker 3: would get in the mouth of the animal and take hold.
Speaker 3: In some cases, I'm sure that flies would also lay
Speaker 3: eggs in the mouths of the newborn calves. You couldn't
Speaker 3: use any medicine, just remove the worms and hope you
Speaker 3: get them all. Some cases would be so bad that
Speaker 3: an animal might lose some of their teeth. It sure
Speaker 3: wasn't a job for anyone with a queasy stomach end quote.
Speaker 2: Oh, I've seen some pictures of that in like sheep's mouths,
Speaker 2: and it's so awful, awful, and.
Speaker 3: So you're trying. I mean, imagine you have a herd
Speaker 3: of cattle and you have to spend so much of
Speaker 3: your time trying to do this. Like it was a
Speaker 3: losing battle too, because, as you mentioned, infected lesions will
Speaker 3: attract more flies, so they use a quote straw color
Speaker 3: and often bloody discharge that attracts more flies, resulting in
Speaker 3: multiple infestations by hundreds to thousands of maggots of all sizes.
Speaker 3: Death is inevitable unless the animal is found and treated.
Speaker 3: The horror of screwworm infestations was deepened by how inevitable
Speaker 3: they seemed. You could react, you could treat the animal,
Speaker 3: but how do you prevent them from attacking in the
Speaker 3: first place. Part of the issue was a misunderstanding of
Speaker 3: the screw worm's biology, which was only corrected in nineteen
Speaker 3: thirty three. So for decades the screw worm was misidentified
Speaker 3: as just a regular type of blowfly, one who primarily
Speaker 3: fed on carrion and only on live flesh sometimes. So
Speaker 3: it was like, okay, opportunistic live flesh feeder, And so
Speaker 3: it was thought, okay, well, if you get rid of
Speaker 3: all the carcasses on your range land, that is going
Speaker 3: to prevent the screw worm from see being a problem.
Speaker 3: But since its exclusively on live flesh, it actually doesn't
Speaker 3: really do anything right, And so recognizing that aspect of
Speaker 3: its biology was a huge step forward, and that happened
Speaker 3: in nineteen thirty three, and around the same time there
Speaker 3: was another development that would revolutionize the way that we
Speaker 3: dealt with screwworm, and that was a newly minted entomologist
Speaker 3: joining the cause. In nineteen thirty four, Edward F. Nipling,
Speaker 3: a recent master's graduate from Iowa State University, started work
Speaker 3: at the USDA, where he was tasked with, among other things,
Speaker 3: collecting and counting screwworm flies cotton traps. Nippling was no
Speaker 3: stranger to screwworm. He grew up on a farm in
Speaker 3: rural southern Texas. He was one of ten kids, and
Speaker 3: the farm is how they produced most of the food
Speaker 3: for this his big family, so they would all be,
Speaker 3: you know, take part in dealing with the livestock, and
Speaker 3: he described removing, having to remove and look out for
Speaker 3: screw worms among other agricultural pests. Before he went to college,
Speaker 3: he was aware of screwworm and the problems that it
Speaker 3: could cause, but it was at university that he gained
Speaker 3: a fuller perspective of how much insects have affected humanity,
Speaker 3: not just as livestock or agricultural pests, but also as
Speaker 3: vectors of disease, killing hundreds of millions of people around
Speaker 3: the world. He knew that control of these disease vectors
Speaker 3: and agricultural pests could save lives and livelihoods, and so
Speaker 3: while working at the USDA, he got to see firsthand
Speaker 3: how powerful some insecticides were, like DDT, which was just
Speaker 3: sort of like, you know, really this revolutionary thing, kill
Speaker 3: it all, and also how quickly they lost their potency
Speaker 3: as insects grew resistant. Not to mention the toxic impacts
Speaker 3: of some of these pesticides, right, and so he realized
Speaker 3: that a different, more proactive approach was needed. And play
Speaker 3: the clip titled screw Worm two.
Speaker 2: Okay, this is so fun. Screw Worm two.
Speaker 4: What we really need is some way to control the
Speaker 4: screw worm before they attack the animals. And rather than
Speaker 4: the just wait until after the animals had the tree worm,
Speaker 4: then try to control it. I realize that you would
Speaker 4: never never really control the screw worms that way. What
Speaker 4: we needed was some preventing major But how to control
Speaker 4: the screw worm on hundreds of thousands of square miles
Speaker 4: of territory, of course seem like tremendous undertaking, and the
Speaker 4: use of insecticides something like that seemed out of the question,
Speaker 4: and no doubt was. But then I conceived the idea
Speaker 4: that perhaps we could rear of the screw worm and
Speaker 4: have it some genetic deficiency, that then it would release
Speaker 4: and release those genetically deficient insects into the population. They
Speaker 4: would mate with the normal, normal flies and transmit to
Speaker 4: detrimental characteristics. Just how I came to that conclusion, I
Speaker 4: really have a little difficulty even today, but.
Speaker 3: Is amazing.
Speaker 2: He's like, I just kind of knew he had to
Speaker 2: do it. I don't know why I knew it, but
Speaker 2: I did.
Speaker 3: He's like I did. Yeah, He's like, I don't know.
Speaker 3: I have this brilliant idea and I have no idea
Speaker 3: how I came up with it.
Speaker 2: I love that.
Speaker 3: I love that. So that was Yeah, that was That
Speaker 3: was doctor Nippling himself, interviewed in January two thousand as
Speaker 3: part of an oral history project for the Rural Eradication Program. Yeah.
Speaker 2: Wow.
Speaker 3: And so what he's talking about here is what you
Speaker 3: mentioned AARON, which is the sterile insect technique, which is
Speaker 3: an insect control measure where large numbers of flies are
Speaker 3: made sterile and then released, ultimately leading to a massive
Speaker 3: decrease in wild population sizes, and the idea behind this
Speaker 3: is that the sterile males are really that are released,
Speaker 3: will mate with the females, they won't produce any eggs,
Speaker 3: and so there will be fewer and fewer screw worms
Speaker 3: over successive generations. And there are a few aspects of
Speaker 3: the screw worms biology that help this technique to be successful.
Speaker 3: The first is that screw worms, like you said aaron,
Speaker 3: tend to mate just once, and so if they mate
Speaker 3: with a sterile male, there's no viable offspring. Yeah, that's what.
Speaker 2: And the females mate once, but the males mate like
Speaker 2: up to ten tonal times. Yes, yes, so one sterile
Speaker 2: male could be mating with ten non sterile females and
Speaker 2: then they're not laying any eggs.
Speaker 3: Yep, yep, it's And then the second thing is that
Speaker 3: in the screw worm affected areas in the US, which
Speaker 3: is more like subtropical, only a small proportion can survive
Speaker 3: over the winter, and so if you hit that area
Speaker 3: hard enough with steril flies one year, you can really
Speaker 3: make a dramatic impact, and so that.
Speaker 2: Can really reduce that population size to begin with. That
Speaker 2: actually makes a lot of sense.
Speaker 3: Yeah, nippling wasn't the only one to come up with
Speaker 3: this idea or idea similar to this, like eradication or
Speaker 3: elimination via sterilization. There were a few other scientists that
Speaker 3: also proposed something similar in like the nineteen thirties and forties,
Speaker 3: but he was really the only one or the first
Speaker 3: one to get it off the ground, and for a
Speaker 3: number of years, you know, after coming up with this idea,
Speaker 3: he was like, Okay, he had the idea first, and
Speaker 3: then he was like, how do I actually implement this,
Speaker 3: Like what how do I make them sterile? Yeah, and
Speaker 3: he a colleague in nineteen fifty was like, hey, have
Speaker 3: you have you heard of this paper? Have you read
Speaker 3: this paper by HJ. Mueller? He used X rays to
Speaker 3: make Drosophola fruitflies steryl In nineteen twenty eight, that's when
Speaker 3: the paper was published, and Mueller had actually been awarded
Speaker 3: the Nobel Prize in Physiology or Medicine in nineteen forty
Speaker 3: six for what he had shown in that paper that
Speaker 3: mutations can be induced by X rays. And this, of
Speaker 3: course like alerted the public to the dangers of radiation
Speaker 3: and was like part of the whole like oh god,
Speaker 3: you know, oh no, when Nippling read this paper, he
Speaker 3: was like, oh my god, this this is it. This
Speaker 3: is what I've been looking for, right, you know, I mean.
Speaker 2: Paraphrase my flies.
Speaker 3: Yeah, And so he reached out to Miller to be like, hey,
Speaker 3: do you think that I could use X rays to
Speaker 3: make screw room sterile? And Mila was like sure, Like
Speaker 3: I think that sounds great real yeah, And so Nippling
Speaker 3: borrowed an Army hospital X ray unit to give it
Speaker 3: a go, and it worked, like not only were the
Speaker 3: males sterile, but the females that mate it with them
Speaker 3: were also effectively made sterile because again they only reproduced once.
Speaker 3: And later they switched from X rays to like other
Speaker 3: methods of radiation, which gave more consistent results. But you know,
Speaker 3: once they tested this out in the lab, all they
Speaker 3: had left to do was actually, you know, see if
Speaker 3: it worked in real world settings. And the first trials
Speaker 3: were carried out beginning in nineteen fifty one on Santabel
Speaker 3: Island in Florida, and when it was two hundred to
Speaker 3: three hundred steril flies were released each week. How did
Speaker 3: they get so many flies, you might ask? They had
Speaker 3: to rear them in the lab. And because these live
Speaker 3: on you know, like flesh. They used ground meat and blood. Iaine,
Speaker 3: just like the smell of that rearly.
Speaker 4: I feel like I.
Speaker 2: Read several papers where people were talking about the smell
Speaker 2: and like the process of finding the right Actually read
Speaker 2: a really interesting one about the lures that they use now,
Speaker 2: like when in their monitoring programs they have a loom.
Speaker 2: The lure is called swarm lure. I think we're on
Speaker 2: version four, and it's like this concoction that they made
Speaker 2: based on looking at what are all of the scents
Speaker 2: and the things that are emitted by the meats and
Speaker 2: the blood and the overposition fluid and all of this
Speaker 2: other stuff to try and make a lure to attract them.
Speaker 2: And it's like a lot.
Speaker 3: It's so gross. I love that though, I know. Yeah,
Speaker 3: I mean that, like I don't. That seems to me
Speaker 3: like complete alchemy, Like that's magic to be able to
Speaker 3: be like, what are these compounds? Let's make this.
Speaker 2: There was so many people that you have I doing
Speaker 2: stuff like that, but for agricultural pets.
Speaker 3: Agriculture, yeah, yeah, it was just it all sounds it
Speaker 3: all is amazing to me. I love it. Yeah. But anyway,
Speaker 3: so with the Sannibal Island, you know, real world experiment.
Speaker 3: The screwroom fly populations did drop over a couple of years,
Speaker 3: but they weren't erradical. I mean, and they dropped dramatically,
Speaker 3: but they weren't eradicated entirely. And that's probably because fertile
Speaker 3: female flies flew over from the mainland. But like, and
Speaker 3: what they really needed I think what the US government
Speaker 3: was looking for outside of the USDA, but like the
Speaker 3: you know, the people who were providing the funding, were like,
Speaker 3: we need one hundred percent perfect eradication, must be eradicated, right, yeah,
Speaker 3: and so this is kind of this yeah, and so
Speaker 3: they were like, we got to do something else, like
Speaker 3: what what else? What else? But this So there was
Speaker 3: a kind of a lukewarm reception to these results, and
Speaker 3: so the US government wasn't really keen on continuing trials.
Speaker 3: They were like, we tried it, but I'm not sure.
Speaker 3: But then there was an agricultural officer on the Dutch
Speaker 3: controlled island of Kurrasau who reached out to Nipling for
Speaker 3: help with their screwworm problem, which was huge in nineteen
Speaker 3: fifty four. Nippling was like, let's do this. So that
Speaker 3: dropped more sterile flies on to currasau and screw wrooms
Speaker 3: were eradicated within fourteen weeks, which is four to five generations.
Speaker 2: Fourteen weeks, Yeah, eradicated, eradicated. Wow, I didn't realize it
Speaker 2: was that fast. That's bananas fast.
Speaker 3: And so this, finally, this was like proof positive that
Speaker 3: Nipling's idea could work, and so the US government was like, Okay, sure,
Speaker 3: I guess and the dream of actual widespread screw worm
Speaker 3: eradication got a whole lot closer to reality, and it
Speaker 3: demonstrated that you could effectively control agricultural pests without the
Speaker 3: use of toxic substances like DDT and actually, in the
Speaker 3: like one of the last chapters of Silent Spring, Rachel
Speaker 3: Carson wrote about nipling work as like a hopeful path
Speaker 3: for the future, like we can use biocontrol in a
Speaker 3: way that doesn't like destroy the environment. Yeah, wow, it's
Speaker 3: very interesting. And so construction on bigger fly rearing facilities began,
Speaker 3: including one that was capable of producing two hundred million
Speaker 3: flies a week, which was a feat that required one
Speaker 3: hundred and twenty tons of meat, one hundred and fourteen
Speaker 3: thousand liters of water, and thirty eight thousand liters of
Speaker 3: blood each week. Would you like to know what kind
Speaker 3: of meat I really got into the the round? Okay,
Speaker 3: it included horse meat, whale meat, and ground up nutria.
Speaker 3: Those whale meat listen. I don't know. Later on, I
Speaker 3: don't think that this stretch. I think that they were like,
Speaker 3: this is not sustainable. We need to do something else.
Speaker 3: And so they developed like a gelled substrate that was
Speaker 3: like dried cow blood, egg milk substitute, and some formaldehyde
Speaker 3: to prevent it from spoil. So they found something else
Speaker 3: that was less not yeah, yeah, And so after they
Speaker 3: constructed these fly wearing facilities, they were like, let's get
Speaker 3: this going. And so in the early nineteen sixties and
Speaker 3: eradication program began that targeted the entire southwestern US. By
Speaker 3: this point in time, screworm had been eradicated from Florida
Speaker 3: by the late nineteen fifties, and so over that decade.
Speaker 3: Over the nineteen sixties, screwroom populations plummeted erin if you
Speaker 3: will play the clip titled screwworm three.
Speaker 5: Okay, in this half of our century, man has conquered
Speaker 5: the atom, the frontiers of space, the depths of the ocean,
Speaker 5: could not this advanced technology be applied to controlled pests
Speaker 5: with even greater effectiveness and safety. Within the last decade,
Speaker 5: radioactive cobalt sixty has been used to sterilize millions of
Speaker 5: pupie of the male screwworm fly, whose parasitic larvae breeding
Speaker 5: in the flesh of cattle, beer, and other animals posed
Speaker 5: a major problem to our livestock industry in the southern
Speaker 5: half of the nation. Once the pupie developed, huge numbers
Speaker 5: of sterile male flies were dropped over infested areas to
Speaker 5: mate with female flies, soon drastically reducing the population of
Speaker 5: a major threat in America.
Speaker 2: So that was them doing the irradiation, right, yep, Yeah,
Speaker 2: that was them dropping Yeah.
Speaker 3: So that video is from the same clip that I
Speaker 3: played at the start of this, from nineteen nineteen sixty
Speaker 3: nine clip. And despite the haunting music, like the narration
Speaker 3: ends quite optimistically, right, like this is the end of scrooms.
Speaker 3: We're starting to see like we are conquering right. This
Speaker 3: weird by the way that the video I don't know
Speaker 3: if I mentioned this, but the video is titled who
Speaker 3: Shall Reap? Yeah, it's kind of anyway, The whole video
Speaker 3: is great.
Speaker 2: So this is a total side note, But it's so
Speaker 2: interesting to watch these old videos that are so like
Speaker 2: slow and the way that they're like the narration is
Speaker 2: like this, and then like even the clips of everything,
Speaker 2: and I'm like, if this was today, it would be.
Speaker 3: Like screwworm like one thousand cuts, like a million cuts.
Speaker 2: Yeah, you never actually see a fly because it would
Speaker 2: just be like like.
Speaker 3: Anyways, education by a million cuts. It's true, but yeah,
Speaker 3: so but this, I feel like the optimistic ending from
Speaker 3: that clip did play out for a while, like that
Speaker 3: is the way that it was. It was looking at
Speaker 3: least in the southwestern US. But the feeling was unfortunately
Speaker 3: short lived because outbreaks of screw worm began popping up
Speaker 3: in nineteen seventy two to nineteen seventy six and then
Speaker 3: nineteen seventy eight as well, And you know what was
Speaker 3: going on. Part of it was suitable conditions for screw
Speaker 3: worm development, so like it was a period of warmer
Speaker 3: and wet weather that provided just more habitat. And then
Speaker 3: another was reduced care for livestock, so like fewer and
Speaker 3: less frequent inspections. Once you think screw worms are gone,
Speaker 3: one gets through that one starts.
Speaker 2: A huge problem you're not checking as much.
Speaker 3: Yeah, But these were I think relatively minor factors compared
Speaker 3: to the real reason for these outbreaks, and that is
Speaker 3: that parasites don't respect arbitrary political boundaries.
Speaker 2: No, they don't.
Speaker 3: They don't. And so the eradication program successful as they
Speaker 3: were only focused on the US side of the border
Speaker 3: with Mexico. And since these flies can travel up to
Speaker 3: one hundred and eighty miles or two hundred and ninety kilometers,
Speaker 3: fertile flies could easily travel to treated areas. That's a
Speaker 3: huge flight range. It's wild such a huge flight range. Yeah,
Speaker 3: and so the flight range though of these of these
Speaker 3: flies was not known when they started the eradication program.
Speaker 3: I think this was like one of the lessons learned
Speaker 3: right away. Yeah. And so after the first of these
Speaker 3: bad outbreaks in nineteen seventy two, which there was ninety
Speaker 3: five thousand cases were recorded, I'm sure that it was
Speaker 3: actually higher than that, the two governments, the US and
Speaker 3: Mexico signed the Mexico United States Screwworm Eradication Agreement, and
Speaker 3: about ten years and a giant fly rearing facility later
Speaker 3: capable of producing five hundred million sterile flies per week. Unbelievable.
Speaker 2: The numbers are unfathomable.
Speaker 3: Truly, truly, but things started to look pretty good. Things
Speaker 3: were looking actually pretty great. By nineteen ninety one, all
Speaker 3: of the US and Mexico were declared free of screwworm.
Speaker 3: And there was a scary blip from like nineteen eighty
Speaker 3: eight to nineteen ninety two when infected cattle were brought
Speaker 3: into Libya infested with the New World screw worm, and
Speaker 3: then that made people super concerned about like, hey, this
Speaker 3: is gonna take over, Like this is going to spread
Speaker 3: everywhere Africa, Middle East, Europe, And so a bunch of
Speaker 3: sterile flies were released, and by June nineteen ninety two,
Speaker 3: the region was declared screwworm free. And this really demonstrated
Speaker 3: the importance of well, first of all, it demonstrated the
Speaker 3: power of the steril fly, the sterile insect technique, and
Speaker 3: the importance of thoroughly inspecting livestock for possible sides of infection.
Speaker 3: But that can be difficult to do. But do you
Speaker 3: know who's really good at it? Dogs?
Speaker 4: Dogs.
Speaker 3: Yeah, there are dogs that have been trained for this
Speaker 3: purpose today. And I think the first screw worm detection
Speaker 3: dog was there's a paper. His name was Casador, which
Speaker 3: means hunter, and he was trained by researcher John Welch
Speaker 3: to work at quarantine and inspection stations and he had
Speaker 3: a success rate of ninety nine point seven percent. And
Speaker 3: the only time that he didn't identify is when he
Speaker 3: had like some gi bug and so he was sick
Speaker 3: and needed to rest.
Speaker 2: Oh, they made him work, even though we sit.
Speaker 3: I don't think they realized. Yeah, but it's like, it's
Speaker 3: so sweet the paper I have it. It'll be on
Speaker 3: our in our show notes or like our in our
Speaker 3: on our website, and it's he's thanked in the acknowledgments.
Speaker 2: Oh, that's so cute it is.
Speaker 3: And his leash and his ashes are in the National
Speaker 3: Agricultural Library in the schworm unit.
Speaker 2: Wow.
Speaker 3: No, anyway, isn't that. I just loved that. We'll put
Speaker 3: a picture of cat. We'll try to find a picture
Speaker 3: of KZ somewhere. There are lots of them. But so anyway.
Speaker 3: Over the nineteen nineties and into the two thousands, eradication
Speaker 3: efforts in the Western hemisphere continued into Central America and
Speaker 3: the Caribbean, and they were largely successful, at least for
Speaker 3: a time. But eradication has proved to be a moving target,
Speaker 3: and screwworm has re emerged in areas where it was
Speaker 3: previously declared eradicated. And in light of that, I want
Speaker 3: to play just one more clip for you, So play screwworm.
Speaker 4: For what lesson can we learn from the screw worm program? Well,
Speaker 4: to me, it's it's a remarkable program, and I sometimes
Speaker 4: wonder how it ever materialized in the first place. In
Speaker 4: our they were able to get this program underway, But
Speaker 4: it confirms something that I'm absolutely confident of, and this
Speaker 4: is that if we're going to deal with major insect
Speaker 4: pest problems, we're going to have to deal with from
Speaker 4: an area wide standpoint. That we cannot deal with these
Speaker 4: best problems by just trying to control them, uh a
Speaker 4: year after year on a farm or farm basics. Just
Speaker 4: like we never would have controlled the screw in that way,
Speaker 4: we will never control the bow weaver or or the
Speaker 4: corn airworm, or the cabbage loafer or carling moth or whatever.
Speaker 4: You will never control these insects this way. I mean,
Speaker 4: you control them, but you will not reduce eliminate the
Speaker 4: threat that but there is or possibility and that we
Speaker 4: can do the same thing for dozens of other insects.
Speaker 2: Oh, Aaron, I love that because that's like the conclusion
Speaker 2: at the end of my section as well.
Speaker 3: I know it. Just like I said, that interview was
Speaker 3: recorded in January two thousand and the lesson is as
Speaker 3: relevant today as it was then.
Speaker 2: And extends so far beyond just insect and agricultural pests.
Speaker 3: Yes, it's doctor, I mean, thank you. It's public health.
Speaker 3: Yeah yeah, like global yeah, global health, all of that.
Speaker 3: And so yeah, with that, Aaron, I'll turn it over
Speaker 3: to you to tell me where what the people really
Speaker 3: want to hear, which is where we are with screwworm today.
Speaker 2: Oh, let me tell you it's not great. Yeah yeah,
Speaker 2: every week still to this day, for decades now, planes
Speaker 2: drop millions of sterilized insects, which are grown and irradiated.
Speaker 2: They use slightly different techniques now in a lab in Panama.
Speaker 2: They've moved. The labs are no longer, the rearing facilities
Speaker 2: are no longer in the US, no longer in Mexico.
Speaker 2: They are in Panama, and millions of sterilized insects are
Speaker 2: dropped across the Darien Gap and the very first part
Speaker 2: of Columbia in an attempt to keep screw worms out
Speaker 2: of Central and North America. And yet despite all the
Speaker 2: success that you talked about Erin in twenty sixteen, I
Speaker 2: think is when the first like rumblings that things were
Speaker 2: not all perfect began in modern most modern times, because
Speaker 2: there was an outbreak in Key West, Florida. Right it
Speaker 2: was relatively quickly contained, but the deer population in Florida
Speaker 2: took a hit because of this. And despite the incredible
Speaker 2: successes of the program, the truth is that New World
Speaker 2: screwworms are still present. This fly is still present throughout
Speaker 2: nearly all of South America, as well as many islands
Speaker 2: in the Caribbean, including Cuba, Haiti, and the Dominican Republic.
Speaker 2: And so since twenty twenty three, so in the last
Speaker 2: two years, cases have increased within like North and Central
Speaker 2: America from an average of about twenty five cases per
Speaker 2: year to six thousand and five hundred in one year
Speaker 2: in twenty twenty three. Okay, And so since twenty twenty three,
Speaker 2: flies have been reported in Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua,
Speaker 2: and Mexico, with more than twenty thousand new outbreaks reported
Speaker 2: like individual outbreaks as of August twenty second, twenty twenty five,
Speaker 2: per the World Organization of Animal Health, the World Okay,
Speaker 2: most all of these outbreaks are in livestock animals. There
Speaker 2: are some cases in domestic animals. There have also been
Speaker 2: cases in humans, but some of these outbreaks have been hundreds,
Speaker 2: if not thousands of animals infected. So right now on
Speaker 2: the APHIS website, which is the Animal and Plant Health
Speaker 2: Inspection Service as of September second, twenty twenty five, there
Speaker 2: are several outbreaks ongoing in Mexico that are of serious
Speaker 2: concern to the US government, which has resulted in the
Speaker 2: US government shutting down all live livestock like live cattle
Speaker 2: trade between Mexico and the US. There have been over
Speaker 2: five thousand, five hundred total cases in Mexico currently as
Speaker 2: of September second, seven hundred and seventy seven active cases
Speaker 2: and at least one confirmed case in a human in
Speaker 2: the US, which was a travel associated case with someone
Speaker 2: traveling from Al Salvador and coming back with an infection
Speaker 2: they've recovered. In twenty twenty four, in Costa Rica, there
Speaker 2: were seven human cases that were reported, including one death,
Speaker 2: and in Nicaragua, there were one hundred and twenty four
Speaker 2: cases in humans in the last year. But this is
Speaker 2: not the case that we as humans need to start
Speaker 2: panicking that we're all going to be infected with screwworm.
Speaker 2: That's not the situation here. But what this does show
Speaker 2: us is the fragility of our eradication efforts and the
Speaker 2: necessity of these one health approaches, and that they don't
Speaker 2: face the kind of budgetary cuts that we see currently
Speaker 2: playing out across every single health agency in the.
Speaker 3: US budgetary and like intellectual cuts. Yes, I have a
Speaker 3: question about so in terms of the numbers, we've talked
Speaker 3: about humans, we've talked about livestock, maybe a little bit
Speaker 3: of like domestic animals. What about wildlife?
Speaker 2: Great question, what about wildlife? Certainly some of these infections
Speaker 2: are happening in wildlife, but we just don't have as
Speaker 2: good a numbers on wildlife populations. Okay, but that is
Speaker 2: definitely a huge concern, right because not only is that
Speaker 2: like a potential reservoir, but it's also just then we're
Speaker 2: affecting livestock populations and like the effects of this eradication
Speaker 2: program on benefiting the health of wildlife should not be
Speaker 2: understated as well too. Yeah, so that's kind of like
Speaker 2: where we stand with like what's going on with current
Speaker 2: with current outbreaks. The live cattle market in the US
Speaker 2: was valued in twenty twenty three at three billion dollars
Speaker 2: per year, and it's gone up since then. And the
Speaker 2: USDA says that estimates currently that an outbreak, like a
Speaker 2: true outbreak of screwworm in the US, could end up
Speaker 2: costing something like ten billion dollars in losses.
Speaker 3: So this is this is something that I kept coming
Speaker 3: across to was the screw worm eradication program, which has
Speaker 3: cost money.
Speaker 2: Cost money. It costs million dollars a year.
Speaker 3: Yeah, it has saved so much in terms of revenue
Speaker 3: from livestock people's livelihoods, And I think, what is like
Speaker 3: so it's like, okay, well we can do this. We
Speaker 3: did this here in the US, we did this in Mexico,
Speaker 3: we did this throughout a lot of Central America and
Speaker 3: in South America. It's like, well, they couldn't afford these programs,
Speaker 3: but they are losing money year after year. And so
Speaker 3: it's like again it comes back to this, has this
Speaker 3: is an area wide program. I lack the words the
Speaker 3: articulation needed to express this, but like this should be
Speaker 3: a continental a hemisphere effort one.
Speaker 2: Hundred and so right now what the US is doing
Speaker 2: is going absolute ham They are reopening facilities in Texas,
Speaker 2: they are rebuilding a facility in Mexico. They're going to
Speaker 2: spend tens of millions of more dollars to start breeding
Speaker 2: flies in the US and Mexico for sterile insect technique.
Speaker 2: It is going to take years, at least eighteen months
Speaker 2: is the current estimate for these to happen and get
Speaker 2: up and running. This is essential that it happens right now.
Speaker 2: And they have this like five point plan which all
Speaker 2: sounds very much like war language. But they are taking
Speaker 2: this very seriously. And I think there was a paper
Speaker 2: from two thousand actually that really exemplified what is the
Speaker 2: true kind of hero of the screwworm story, and that
Speaker 2: is that in order for the success that we have
Speaker 2: had thus far to happen, a ton of cooperative agreements
Speaker 2: had to exist between countries for this eradication program to
Speaker 2: take place and to be successful, because yeah, flies don't
Speaker 2: give a crap about our national borders, the same way
Speaker 2: that infectious diseases like COVID don't honor these artificial divisions.
Speaker 2: Even though this program is currently kind of at risk
Speaker 2: right and we're having to re up it.
Speaker 3: It was only.
Speaker 2: Possible in the first place because countries decided it was
Speaker 2: important enough to invest in and to work together, despite
Speaker 2: the difficulties and the financial agreements that had to be
Speaker 2: made to coordinate the implementation of this program, but they
Speaker 2: agreed it was important because they could make a lot
Speaker 2: more money.
Speaker 3: I mean, and because the vustock industry.
Speaker 2: Yeah, the livestock industry and the funding around this were
Speaker 2: considered important enough. The absence of these screw worms in
Speaker 2: the US is estimated at least at a minimum to
Speaker 2: be a one point three billion dollar benefit every single year,
Speaker 2: So spending a few million dollars to keep this program
Speaker 2: running is nothing compared to that benefit. It would be
Speaker 2: great if we could recognize that this is also true
Speaker 2: for so many other things besides just screwworm, and yes,
Speaker 2: expanding this to be able to eradicate it throughout its
Speaker 2: entire range rather than just stopping at the border of
Speaker 2: Columbia would go a really long way to improving the
Speaker 2: lives of humans and livestock and wildlife. Across the entire
Speaker 2: western hemisphere.
Speaker 3: Yep, uh huh.
Speaker 2: And it is also possible that this could happen for
Speaker 2: Old world screwworm. They have very similar mating habits, so
Speaker 2: they could also benefit from sterile insect technique programs. But
Speaker 2: there just hasn't been as much of this collective agreement,
Speaker 2: infrastructure build up, and the money upfront to be able
Speaker 2: to do this where Old World screwworm, that's really hard
Speaker 2: for to say, is endemic, and so the programs that
Speaker 2: have tried to get up and running there have not
Speaker 2: been as successful. There's a lot of interest too in
Speaker 2: like creating like newer techniques to make this even more
Speaker 2: effective and even more cost saving, like doing transgenic flies
Speaker 2: so that you're only really rearing male flies, because right
Speaker 2: now you're rearing indiscriminately female and male flies. So if
Speaker 2: you could kind of whittle down the female population so
Speaker 2: that you're only releasing male flies, you're kind of doubling
Speaker 2: your efforts but at a lower cost. But like all
Speaker 2: of that is amazing. This is an amazing program. It
Speaker 2: is incredible. Let us apply this success to other facets of.
Speaker 3: Public health, use it as a framework. Like this, I
Speaker 3: mean and it is like it's it is.
Speaker 2: But it's also not. Yeah, and that screw worm baby.
Speaker 2: Oh wow, what a fascinating thing. Though, like also just
Speaker 2: fe like the entomology of it all.
Speaker 3: I love the entomology. I just also I love I
Speaker 3: think this is when I was like, oh, I could
Speaker 3: spend weeks just digging around on the USDA, like the
Speaker 3: National Agricultural Library website, and that the archives, the Internet archive.
Speaker 3: Like I was having a blast looking through these oral
Speaker 3: histories and the transcripts, and I'm like, there are more
Speaker 3: that aren't digitized. I want them. I reached out to
Speaker 3: a library and was like, can you help me find this?
Speaker 3: And they did, and I'm just like, I love library.
Speaker 3: I love libraries. I love librarians. It's and also I
Speaker 3: think I had no concept how huge this program was
Speaker 3: because you can't find a lot of other agricultural well
Speaker 3: maybe agricultural pest videos, but like other disease videos from
Speaker 3: the nineteen fifties and sixties and so on, not so much.
Speaker 3: Like this is a huge effort and it was a
Speaker 3: huge success story and it can still be Yeah, and
Speaker 3: it will be.
Speaker 2: I think it will be successful. The funding is going there.
Speaker 2: It's happening. Yeah, but yeah, can it go further? That
Speaker 2: would be cool, That'd be cool.
Speaker 3: Should we tell the people where they can find more information?
Speaker 2: Should okay?
Speaker 3: Should I have linked to all of his videos? Love it?
Speaker 3: I have a ton of sources, but I'm going to
Speaker 3: shout out too in particular. So one was the website
Speaker 3: the Stop screw Worms. It's a it's an online like
Speaker 3: digital collection, so it's selections from the screwroom Eradication Collection
Speaker 3: on the National Agricultural Library USDA websites.
Speaker 5: Very cool.
Speaker 3: And then also there was fun, a couple of fun
Speaker 3: chapters in a book, a popular book published in nineteen
Speaker 3: eighty four called The Dragon Hunters by F. Graham, And
Speaker 3: it was these two chapters that I read focused on
Speaker 3: a screwroom and screwroom eradication.
Speaker 2: Love it. I had a bunch of papers I don't
Speaker 2: even know erin. The one that I mentioned already that
Speaker 2: I did really enjoy was by Wiss from two thousand
Speaker 2: called screwworm Eradication in the Americas that focused a lot
Speaker 2: on like the success of these collective agreements and things
Speaker 2: like that. There was also a paper from twenty seventeen
Speaker 2: that was review of research advances in the screwworm eradication
Speaker 2: program over the past twenty five years that was really interesting.
Speaker 2: And then a couple of papers that are like quite
Speaker 2: old from like the eighties and nineties about the screw
Speaker 2: worm behavior and biology and things like that. And then
Speaker 2: I also have links to the USDA website where they
Speaker 2: have their new World Screwworm Domestic Readiness and Response Policy
Speaker 2: Initiative document which is really interesting to read through. And
Speaker 2: then also the updates if you would like them, because
Speaker 2: I'm sure the numbers will be different by the time
Speaker 2: that this episode comes out, But on the APHIS website
Speaker 2: you can find those, like updated data on what the
Speaker 2: outbreaks look like in Mexico, what other cases have been reported,
Speaker 2: and things like that. You can find it all on
Speaker 2: our website This podcast will Kill You dot Com.
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