Episode 25 DWP- New World Screwworm w/Dr. Samantha Wisely

Dr. Samantha Wisely, PHD joins host Josh Newton for an update on New World Screwworm. Enjoy

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This podcast is built around real-world experience, collaboration with producers and veterinarians, and nearly three decades of hands-on work across North America. The goal is simple: provide practical insight that helps producers make better decisions for herd health, genetics, and long-term success.

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Transcript

SPEAKER_01 0:05

Welcome to the Deer Wizard Podcast, conversation shaping the deer industry. I'm your host, Josh Newton, the Deer Wizard. Through interviews, advocacy, and industry news, we deliver field-proven insights to help producers build better herds.

SPEAKER_02 0:20

Ladies and gentlemen, welcome back to another episode of the Deer Wizard Podcast. We have a great show for you today. We are talking New World Screwworm. We have some direct insights from the field. And we have back Dr. Samantha Wisely from the Cherry Lab at the University of Florida. She has direct insights into New World Screw Worm. We cover some of the basics. I ask her some pretty, you know, high-level uh questions just from a farmer's standpoint. And there's there's um lots of good insights emerging from this uh disease here that's now shown up in North America. I hope you enjoy the show and we want to welcome Dr. Wisley. Dr. Wisely, so good to see you again. Great to be here. So you know, in the world of animal health and disease, things come up and New World Screwworm has shown its face here in the United States officially. Uh, I know that uh with your background, you're very much involved in emerging disease and and um these types of things. Can you just give us like a high-level update on where things are at here in North America? And then we'll we'll jump back and we'll get into the history and um kind of the ecological uh impacts and such.

SPEAKER_00 1:51

Sure, sure. Yeah, so um New World Screwworm showed up approximately two weeks ago in some of the southernmost counties of Texas. That was not unexpected, it had been steadily marching north um all the way up to the border in Mexico for about the past year. And um it crossed the border. And so it was found almost immediately in a couple of counties in Texas, also one in New Mexico. They think that was a dog case, and so they think a dog was brought across the border from Mexico. The other cases have been in livestock, mostly cattle. I think one goat has been involved. There was a little bit of a lull, and then I saw today that there have been more cases in more counties. So we're definitely in an on an expansion phase um throughout Texas.

SPEAKER_02 2:46

Okay. I guess we'll just start in the beginning. What is New World Screwworm?

SPEAKER_00 2:53

Right. So it's a fly, um, and the the screw worm is the actual larva, the maggot. Um, what's unusual about it is that most maggots feed on feed on dead flesh or trash or garbage, but these actually eat live, healthy flesh. Um, and New World Screwworm is not an invasive pathogen. It was in North America and in the United States all the way through the 1970s. And anyone who raised cattle in the 1970s remembers New World Screwworm and the steps that people had to take to keep their cattle safe, to keep um any livestock safe. So this is a re-merging um parasite that we're seeing. Um, and unfortunately, um we're not gonna see it go away anytime soon. I think we're um gonna be in this for a while.

SPEAKER_02 3:52

What is a while?

SPEAKER_00 3:55

I was so I'm on the New World Screwworm Task Force in Florida, and um we're talking years to really beat it back. Um what is needed to beat it back is this the idea of sterile flies. So sterile male flies are released into the wild. Females can only mate once and then they die, and so if they mate with a sterile male, then they don't lay eggs, and so that reduces the population. That's how it was beat in the 1960s and 70s, and so that is um how it's gonna happen again. The problem is we can't make flies fast enough right now to keep up with the problem. And so it's gonna be a while until USDA gets these facilities online. We have one coming online in Texas, one coming online in Mexico, and then there's also gonna be some distribution centers around the United States as well. But but we're talking a year maybe before that comes online. And the flies that we have right now, which come from a USDA facility in Panama, which is where we had contained it for many years, um can't keep up with the sort of geographic area that we're talking about right now.

SPEAKER_02 5:17

Um over the past year, as this has gotten more publicity to it, and there's more articles, and of course, as it creeps further north, you know, you get more interested in in reading stuff, right? This isn't this isn't my uh my cup of tea, so to speak. I'm not super well versed on it. But my understanding is is that um as far as sterile fly production, you know, once it got into you know Mexico, there was there was kind of this this ramp up, that 700 mile mark kind of sticks out in my brain. That might have been you know six or eight months ago, and they were like, hey, we we should we should we have to do something in here because like I guess the facility in Panama I they make what 20 million a week or something like that of the sterile flies? Something hundred mil 100 million a week, 100 million a week. And we we need every bit of those just here, let alone you know what you know Central America needs. Um so what is that? Um, I guess they're what they're converting uh an old air force base or something like that. You want to do you have any additional insight on that?

SPEAKER_00 6:34

There's an air force base, there's another facility. I I know of I know of at least two facilities in the United States that are being built. One is the Air Force Base, one is the the base in Texas. I mean another facility in Texas. Um so right now, all of those Panama flies are being diverted to the United States, so they're not being put anywhere else, right? Okay, which is great, right? Because we want to keep it from spreading as quickly as possible. But it also means that now Mexico, Central America, the populations of flies are increasing because there's now no control there, right? So there's still a lot of population pressure that's building further south from us.

SPEAKER_02 7:17

Okay.

SPEAKER_00 7:18

Um, it's not a great situation. Um, and we're I we are going to have to be vigilant as a nation to really keep this from being devastating. And and I should say this is not just for livestock, right? Wildlife um can be impacted just as easily. Any animal, any animal can be impacted. And and we're talking the what happens is they get the the flies lay eggs into wounds, um, but they can be as small as like a tick bite, right? And then they eat their way inside, and an animal will be dead in about two weeks. So we're talking about deer populations, wild hog populations, you name it. Any of our game species are any of our non-game species are fair game for for this fly.

SPEAKER_02 8:11

I think some of the wildlife agencies that have to control feral hogs may not mind some of those hogs going away. But I I I get your point. And and so, like, obviously, you know, like all your warm-blooded mammals are are susceptible, that would include people. Uh, obviously, we have um we have um come a long way in our our hygiene practices and our our standard of living in our society. So I suspect that you know, if somebody's got a maggot crawling around on their their arm, they're gonna get that taken care of. But um it's it's interesting. Obviously, we've dealt with this before, so like, and there's still I've seen enough, I call them old timers, no offense to them, but I've seen a lot of the you know, especially the cattle ranchers, because we have so many cattle in the United States, right? That's our that's our bread and butter for our our food supply, and you know, beef beef is king. And and those old timers, you know, they they talk about it. I've seen lots of uh various posts of the old uh little vials that they were distributing of the sterile flies. Um it was really interesting. Is like, do you know how long that took for them to kind of quote unquote get that under control and then ultimately, you know, at least eradicate it from our borders to the best of our ability?

SPEAKER_00 9:35

Yeah, I mean it was a couple of decades. Yeah, it was a couple of decades. And and and really, I mean, I heard 10 years being being bantered around today. So 10 years before we can actually beat it back to where it was before. And that's if we're vigilant, right? That's if we sort of maintain what we're doing right now. And we don't, I don't think we have a sense of how far it could spread. I know here in Florida we're really worried about it. We had it here in Florida once before, you know, both Texas and Florida. This is a tropical fly, right? So um it when it gets very cold, when it gets cold, if there's frost, they die out. So in the northern parts, they can go all the way up, certainly to Pennsylvania, but there'll be a summer problem, right? They'll they'll come back down, but they can overwinter in Florida and in southern Texas. And so we're really worried about um about that here.

SPEAKER_02 10:32

Yeah, are they um like just from a visual identifier, not the larva, the fly themselves, are they easily identified? Like if they land on you, would you be like, oh, that's not a house fly, or you can't really tell?

SPEAKER_00 10:46

I I I am not an entomologist, and I do not think I could tell. No, there's no obvious, obvious descriptor.

SPEAKER_02 10:54

Okay. Um so there's other control mechanisms that are obviously going to be implemented. I I saw a couple press releases that uh USDA or FDA or whoever does the drug approvals, you know, they had scheduled Dectamax as a as an example as an emergency uh use for the treatment of of NWS. And um what do you think the the management kind of scheme in total looks like, right? Like we we obviously have a waiting period for these sterile flies. Yeah, like that's that's a fact. We we are going to be waiting. I suspect, I hope that they will just overproduce these things and they will just just dump distribution out to where they're needed, and we'll see collap collapses in population um fairly quickly because the way information spread, at least today with the internet, you know, there's no there was no internet back in the 60s and 70s, right? Well, you can reach the world instantly today. And so like everybody that I know knows what New World Scrum War is. What do you what do you think that overall management scope looks like?

SPEAKER_00 12:12

Yeah. So a couple of things. I mean, the the first one is rapid reporting, if if we find it in a new area. And uh, you know, I really want to make it clear to livestock producers, including deer producers, that um when an infestation zone has been identified, um that does not mean that you can't that that that you are quarantined, right? So so I really want to make that clear. Animals have to be inspected and they have to be cleared, but then they can still be transported within state, and if your state allows it, out of state. Um, so I just think that that's really important to get across because I don't want people to not report because they think it's gonna shut, shut down their business. And the faster they report, the faster they can get their property in that area cleared of those flies, right? And so then the problem goes away more quickly. So that's the first thing. Managing, the first part about managing is reporting when you see it so that we really do know where it is. The second one, I think is I think everybody is now gonna have to be a bit more vigilant about their animals and the treatments that we use for wounds, let's say when we're cutting horns or when um there's umbilical cord wounds, um, we're gonna have to treat those a little bit differently. And and I can't really talk about specific products because literally they are changing daily, and more and more are gonna be coming online. I I know that FDA and USDA are working hand in hand to get more products available, but that's gonna, we're really gonna be changing the way we manage wounds that we create, wounds that occur naturally, and we're just gonna have to be more vigilant in general. And that's tough for deer, right? Because we don't put our hands on our deer every single day. But really, keeping your eye on animals is gonna be super important.

SPEAKER_02 14:21

So I guess from a deer perspective, I think about you know, the fall, and it's still summery conditions. And when I say fall, I mean the end of August through October, right? Like I know that's technically still summer, but that's the fall season for deer farmers anyway. Um and like, you know, having to sedate a buck to move him into a breeding pen, let's say. And so we have a dart wound, right? And so we're gonna have to be aware. Um, even if NWS is not, you know, we're not in a quarantine zone, doesn't mean that those uh those flies aren't there, right? And so uh I suspect that there'll be protocols for these again, these these wound treatments. Um is that is that gonna be something fairly easy to to implement? It's is it gonna be more of a challenge to actually distribute the information to get it in people's hands and minds as opposed to physically implementing these things?

SPEAKER_00 15:27

Yeah. Yeah, that's a that's a good point. I mean, information is gonna be key. And I think getting that information out is gonna be really important. I mean, Cherry, UF, UF in general, Texas AM, I mean, all of us are working together right now to get those informations together. Screwworm.gov is the the national website that has all of that information on there. And they've been very good about keeping up to date about what treatment regimes are available. But I would and and so what these new treatment regimes basically have something that's like that ivermectin along with um antibiotics. Or so really we're we're gonna be treating for anti-parasite treatments along with antibiotics, like he normally would. And and and I'm hoping that that those will be combination drugs, so you don't have to apply a bunch of things at once, right? That we can get it all in one packet. So that's that's sort of I think what USDA and FDA are moving towards. And I think be a spectrum of things available.

SPEAKER_02 16:36

So one of the things I think that um again into the the deer world, I think deer farmers generally have been very resourceful in their fly management because of EHD, right? Different bug, similar protocol, right? And so um I feel like maybe as an industry that we might be a little further ahead in our our pest management, at least in those areas that have been consistently hit with EHD. And I suspect that not that there's a correlation, but climate and weather are are part of this, and where the midge can go as another subtropical bug. Um, I suspect that that NWS could as well. Um is is topical applications, do you think that's gonna be another thing that were gonna be helpful to repel these these um these flies?

SPEAKER_00 17:37

Yeah, absolutely. I think topical is gonna be definitely a part of it. Um I I think you know we want to be judicious. We don't, you know, you I don't think you want to apply it every day to your herd if you're not near an infestation zone. But that's certainly something that you're that that you we may be working towards when we know that a deer farm is in an infestation zone, but maybe they haven't seen that yet. And certainly being vigilant for wounds that either that we create or not. So yeah, and and I think you're absolutely right, you know. I mean, nobody observes every single one of their animals in the herd as much as a deer farmer, right? I mean, it's an everyday eyes on the animal uh thing. And so I think from that point of view, that's a leg up. Um, and you know, animals are not, you know, unless an animal is in a really terrible state of health because of those infestations, you know, the protocol is not to call the animal, it's to treat the animal until it's but it's back into good health, and then that animal can live out the rest of its life. If it's cleared of inspection of not having it, you can move it, you can sell it. So this is a very different beast than say chronic wasting disease and the types of quarantines that are implemented in that situation. So I just I really there's it's a night and day situation when we say the word quarantine.

SPEAKER_02 19:04

Um the only other thing that I I want to touch on with uh with screwworm is um identification. And so um how do you how do you go about telling the difference in these these maggots? Like let's say you had a wound and there was some maggots there, wherever it is, antlers on the body, whatever. What what do you do?

SPEAKER_00 19:28

Yeah, so there's really good resources that show those sorts of of wounds on screwworm.gov. Um, but in general, they're they make this very organized pattern when they feed, they feed head down and butt up, and so you'll see a bunch of maggots all facing downward, and and so you'll just see their little rear end sticking up out of the wound. Um and you know, it's that wound increases in size dramatically um over time. Um you know, we had New World Screw Worm here in Florida in 2016-2017 in the the Key Deer. And it was, I mean, it I am not someone who was familiar with New World Screwworm until we had it then. And it it was a little horrifying to see the amount of damage that they could do to an animal that was left untreated.

SPEAKER_02 20:29

Um so if you wanted to check, right? And again, I have I have screwworm.gov here and the it's gonna be in the show notes. So if you want to access that, you should access it and just just make sure you're updated on what that is. But you can um you can physically collect some of those, right? Like where you you brush them off to to verify, right? And then you take them to a lab or something like that. Is that yes? I thought I saw something on that.

SPEAKER_00 20:58

Yes, absolutely. So um any veterinarian right now has sort of been alerted to that. So you could take them to your public health department, you could take them to your veterinarian, um, uh if you and and they can help you get them to the right place where they need to be to positively identify. There are other maggots that look a bit similar, so definitely want to get those identified professionally.

SPEAKER_02 21:23

Yeah. Okay. Um well, I appreciate you kind of being on the front lines of the the task force, and and I suspect we'll be seeing uh updates from Cherry on on this. I there was something in the newsletter. I I I thought I just you guys had a newsletter last last week. Was it last week? Last week. We did, yeah. So that was I I look over them when I think when I when I get them. I appreciate you doing those because like there's so much stuff, right? There's like six or seven different topics in the last newsletter, they're all like directly related to to what I was we do. So thank you for doing those. Um okay, so uh we'll we'll leave it at that. Um, as you get more information on screwworm, because it is evolving rapidly. Uh if you don't mind, we'll hop on and we'll do a quick show to get it out to to folks.

SPEAKER_00 22:16

Absolutely, absolutely. And please do to check our our website. Um, if you Google UF IFUS Cherry, you'll find us on the website. You can ask an expert. Um if you we have that little part of it. We have lots of resources. Our screwworm resources are being updated almost daily. So yeah, do check in with us. But the the authoritative place and the most recent information, including the most recent indications of where screwworm has been located, is at screwworm.gov.

SPEAKER_02 22:50

Excellent. I'll make sure that both those are are linked in the show. Um thank you so much for coming on today and uh give us an update. We really appreciate it. And with that, stay tuned for another episode of the Deer Wizards Podcast.