Baa's and Bleat's - The AASRP Podcast
Baa's and Bleat's - The AASRP Podcast
New World Screwworm with USDA's Dr. Rosemary Sifford
This month we sat down with Dr. Rosemary Sifford - Deputy Administrator and Chief Veterinary Officer for USDA-APHIS to discuss a zoonotic health threat that is creeping closer to the United States: New World Screwworm. Dr. Sifford explains what New World Screwworm is, why it is a threat to US livestock, and what veterinarians should do if they suspect they are dealing with an infected animal. Veterinarians play a key role in surveillance for diseases such as NWS and early reporting is imperative.
*Note: There are no known cases of NWS in livestock in the US as of the publication of this podcast.*
To learn more about New World Screwworm, visit the USDA-APHIS website: https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm
For updates on the current outbreak in Mexico and Central America, visit the USDA website: https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm/outbreak-central-america
For veterinarians who need help identifying their State Animal Health Official, visit the US Animal Health Association website: https://usaha.org/saho/
To review the USDA fact sheet on NWS for veterinarians, follow this link: https://www.aphis.usda.gov/sites/default/files/factsheet-nws-private-veterinarians.pdf
To complete the NWS module for veterinarians, visit the NAVP Training Module website and complete Module 41: https://www.aphis.usda.gov/nvap/training-modules#:~:text=Module%2041:%20New%20World%20Screwworm,not%20play%20on%20mobile%20devices
To watch the USDA webinar on NWS for veterinarians and animal health officials, follow this link: https://www.youtube.com/watch?v=LxPTfFPxlIk
For insights on treatment options (not prevention) visit the FDA website: https://www.fda.gov/animal-veterinary/safety-health/new-world-screwworm-information-veterinarians
If your company or organization would like to sponsor an episode or if you have questions about today's show, please email Office@AASRP.org
Hello and welcome to Baas and Bleats, the American Association of Small Ruminant Practitioners podcast. Today we have a very special guest, Dr. Rosemary Sifford from the USDA, and she is going to talk to us about New World Screwworm. So, Dr. Sifford, can you tell us a little bit about yourself and your role with USDA?
Rosemary:Yes, thank you all for having me with you today. I am the deputy administrator for USDA's Animal and Plant Health Inspection Service, Veterinary Services, and our unit is responsible for domestic animal health programs as well as trade in animals and animal products.
Michelle:Awesome. Welcome, Dr. Sifford. Thank you so much for joining us. We also are joined by our other host today, Dr. Sarah Lowry. So we're tag teaming this because this is such an important topic that we both wanted to make sure that we helped get the word out. So the other voice that you're going to hear today besides mine is Sarah's. And we're so excited to finally all be on a call together. It's taken a while to get this coordinated.
Sarah:Yeah, thank you. And one of the reasons that Dr. Buckley and I are doing this together is because Dr. Buckley is based down in Texas, where this is a very like real world threat. And me being way up here in New York, it's not something we talk about. It's not something we're as concerned. And so I'm just really, I mean, I've done a lot of reading before we sat down here today, but you know, I was just not as informed on this topic. So I thought we'd be kind of be a good like two ends of the spectrum. Somebody who it's like a an actual, like real world daily concern versus someone who's like, yeah, I've kind of heard of that. So so yeah, so we're gonna tag team, we're gonna learn together. Obviously, this has been in Dr. Buckley's horizon much more than mine. So yeah, I think this is a great topic for us to hit. So, Dr. Sifford, if you could just kind of start us out with kind of even just a basis of like what is New World Screwworm, where you're seeing it, you know, why we're having this conversation, just kind of like the basics to start.
Rosemary:Yeah, so so New World Screwworm is uh a pest that's present in many parts of the world. It's a fly, and the larvae or the maggots from that fly can burrow into the flesh of animals and cause some really serious damage. They can do this on any warm-blooded animal, livestock pets, wildlife, and in rare cases, people. Uh, and what makes these flies unique from other flies is that they, once they're attracted to the wound, unlike other flies that might eat the decaying flesh, these maggots from the screw worm fly will eat living flesh. And so they're a real danger to any animal that has any kind of wound, whether that's you know an animal that's recently given birth or had an injury or a surgical procedure or even a really tiny wound like a scrape or a scratch could be really dangerous. And the the adult screw worm flies generally don't fly very far themselves, particularly if they have animals that they, you know, can lay their eggs in in the area that they are, but they can be very easily moved with animal movements. And so that's one of the reasons that even Dr. Lowry should keep it in mind, because we do have animals coming into the United States from many countries of the world that are affected with screw worms. And those animals, you know, often present to us in airports as well. And and we've had those cases in the past, and it's those accredited veterinarians that first see those pets that are really our first line of defense. And so that's the reason that we think it's really, really important for all veterinarians to be aware of this. And then in terms of where it is, it was eradicated from the United States in the 60s, and we've worked since then with our partners in Central America. We used the sterile insect technique to drive it down to the Darien Gap at the southern edge of Panama, so just between Central America and South America, and we've worked with our partners there to keep it there since that time. In 2024, we started to see cases up into Mexico, the first one in November 2024. And so while we still do not have screwworm here in the United States, because it has moved so far northward, it is of great interest to us, and we're working very closely with Mexico and our partners in Central America to work to drive it back down, you know, as far south as possible, with our goal being the dairying gap again.
Michelle:Great. So yeah, I think it's really important to emphasize New World Screw Room is not currently in the US in livestock, but it is definitely a concern that we need to be aware of that's headed our way. And I also, like Sarah said, I think it's important to emphasize that, you know, there is animal movement, and and Dr. Siffer said animal movement internationally, and even, you know, people from up north in Minnesota and New York are sending their calves down to calf ranches down here in Texas and other warm climates that are going to be the first line if screw worm does come to the US. And so these calves are gonna head back up. And so to me, that's just one of the domestic threats that everyone needs to be aware of this pathogen because we do have so much animal movement here in the US and internationally. So, Dr. Sifford, you kind of mentioned already, but can you tell us a little bit more about what's being done to prevent New World Screwworm from getting to the US?
Rosemary:Yeah, so let me say start a little bit with the work that we've done over all of these years since it was eradicated to the United States. We have a joint facility that we operate with Panama in Panama to produce sterile insects. Sterile insects are the most effective method for eradicating the screw worm fly because a female screw worm only mates once. And so if we put sterile males in the environment and that female mates with a sterile male, then she will not produce any larvae. So that's the reason the sterile insect technique is effective for eliminating the fly populations. And we've jointly had that sterile insect production facility in Panama for a number of years and worked very closely with the Panamanian government to keep the sterile insects in the dairying gap to prevent the flies from moving northward. As they moved northward across Central America, we were working with those countries to try to push them back. And as I said, they made it all the way to Mexico in November. So now we're working very, very closely with the government of Mexico, the National Service for Agrifood, Health, Safety and Quality, which is the Mexican equivalent of the USDA, to work with them to distribute the sterile flies and to do surveillance to make sure we're distributing those sterile flies in the right areas, as well as to work with them on their animal movement control and their treatment of animals that are affected in Mexico. So we're working really closely with them on a number of fronts to try to help them have as much support as they can have to begin to push the fly southward, and then we'll continue that work. We also invested $21 million to help them renovate an existing fruit fly production facility that will allow us to produce 100 million more sterile flies a week. So we have about 100 million a week produced in Panama, and being able to double that production would really help us have more coverage of the areas of concern, both in Mexico and other Central American countries. You might have also heard that on August the 15th, Secretary Rollins had a press conference with the Texas governor Greg Abbott and announced some additional efforts that USDA is taking. So the first is that USDA is investing $750 million to construct a domestic production facility in the United States. That facility is expected to be able to produce 300 million flies a week. And that will, as you can tell, really greatly increase our production ability so that if we need to address multiple areas at once, we'd have that capacity to do that. We're also investing $100 million in new technologies. And so that will involve putting out a request for proposals to have folks put in information about what strategies for treatment or for eradication or control that we might not be fully aware of so that we can support those projects coming forward. We're increasing the number of tick riders along the southern border. Those are part of our team at USDA who normally do surveillance along the border for any stray animals to make sure no animals are bringing cattle fever ticks across. We're going to add to that staff because they're also helping to make sure we don't have any stray animals that might carry new world screw worm larvae across. We're working to train Beagle Brigade dogs to identify New World Screwworm. And then we can use those dogs as a part of our of our tools at our both our land border ports as well as potentially at airports receiving flights from affected countries. And then we're really working hard, as I said, with Mexico to try to make sure that we address all the needs that they have for surveillance and training to help them to make sure to effectively deal with the cases that they have and push them back southward.
Sarah:Great. Man, I wish Beagle Brigades could solve all of our problems because that sounds like the most fun in my mind.
Michelle:I wish that the listeners could have seen both of our faces light up when she said the word Beagle Brigade. Right. I know. But we should probably just carry on with the interview.
Sarah:I feel like you kind of already addressed the next questions, but I'll go ahead and ask it if there's anything you want to add. If it, if the New World Scroom did get to the US, how would we treat infected animals? And let me add to this. So I live right on the Canadian border, right? So say I have a farm that just got a nobody does this really, but a load of cattle from Canada that came from, you know, somewhere else. And I identified it. What would I do? You know, how would I treat those cows? This is a big question. I was actually just reading the FDA Center for Vet Med. They have a page that they're keeping a page updated. It said it was updated last, just on the fourth of this month. So they're keeping it updated, but the treatment things on there are not great. And obviously, as small ruminant people, we're really concerned about people going insane with our dewormers that we're already having so many issues with, with resistance. So I guess I would just like to kind of hear your two cents on all of that.
Rosemary:Yeah. So definitely the first thing I would say is, you know, it's really important for all of us to be vigilant. And so if a producer sees maggots or fly larvae that, you know, that they are concerned about, particularly if they see, you know, an oozing wound and it seems like it's getting larger or things that just don't look like your normal fly strike. But honestly, if you're just not sure if it's normal fly strike, we would strongly encourage them to get in touch with their veterinarian and submit samples. We have a system in place that the larvae can be submitted to the National Veterinary Services Laboratory for identification. And then, of course, if if it's not New World Screwworm, fabulous, you can handle it as your normal fly strike situation. But if it is, that early identification is the really, really important piece for us. We do treat a new world screw worm as a foreign animal disease. And so, you know, if a producer or an accredited veterinarian does see something that they think that they have a concern about and they got in touch with their state veterinarian or their APHIS area veterinarian in charge, and those contacts are on our website, uh, they could, you know, we would facilitate then getting from them the samples, making sure those got into the National Veterinary Services Laboratory for identification very quickly. And we have a system in place there so that, you know, if they're talking to the veterinarian and the veterinarian is highly suspicious, that that goes in as a very high priority. Or, you know, if you're talking to the veterinarian and the veterinarian's like, I think it might just be grubs, you know, we'd still identify it, but but we might not put quite as high a priority on the turnaround time. But but that's the really the first and foremost piece is vigilance is really important, and we're happy to receive samples and identify those, and we're happy to rule out a screw worm and tell you what other species of whether it's grubs or some other blowfile larvae or anything of that nature. But as far as treatment, I mean there's no need for prophylactic treatment. And as you mentioned, prophylactic treatments probably aren't useful and might be and might be harmful in other ways. It's really about that vigilance and identification. And then if we do identify, as you mentioned, FDA Center for Veterinary Medicine has been working hard to provide new information about what treatments are available. So the treatments that are available in the United States do fall under FDA authority. And we've been working very closely with them to keep them informed of the work that they're doing, and they have in turn informed us. And they are working really hard to update their the information available, and they also have added quite a bit of good information for extra label drug use. As you mentioned, there's not really anything that's approved in the United States at this time for New World Screwworm treatment. Because we haven't had new world screwworm, there's no been no reason for anybody to label in that way. But they have a lot of good information there about extra label use. And of course, as you all know, it's really important for particularly food animal veterinarians to be aware of the requirements for extra label use in food-producing animals. In addition to that work that FDA has done, the EPA is also responsible for registered pesticides that might be used against screw worm, and they have a list available for the pesticides that might be valuable. And then we also have a link to that list on our website as well. So I think I would just emphasize again that vigilance and early reporting is the most important thing for us at this time. I would not recommend prophylactic treatment, but be prepared to talk with your veterinarian about the treatments that are available and potential extra label uses.
Sarah:Is there a place that you would recommend veterinarians go to kind of see what the flies and the grubs and the to help them identify like the wounds looking different or something like that? Like, is there I I was on Google there are pictures, but you know, you can't you never know. And I didn't even see any anything on the FDA site about like pictures to help you identify. The flies are pretty different, right? They're pretty striking.
Rosemary:Um, they can be, but I will say, you know, like if you get into a whole bunch of blowflies, it it can be difficult to identify them. And the and the same is true for the larvae. They do have distinctive characteristics, but you know, we've seen cases where there's, you know, a couple thousand larvae with many different species involved. And in those situations, it it could be really difficult, even for you know, someone with a reasonable amount of knowledge to say, yes, this one is is the one that we're looking for. But we do, we just recently posted some some new information on our website, which is the USDA AFUS website under livestock and poultry diseases. You can find our information on screw worms, and we and we put in, we put some information there that does have some pictures. It has some fact sheets for veterinarians, as well as I mentioned that this would happen as a foreign animal disease investigation. So we have our foreign animal disease investigation guide there and some additional information about submitting samples for any veterinarian who might be interested in that.
Sarah:Okay. So I guess the takeaway from that is if you're collecting grubs to send in, collect a lot, because there could be many, many species present, right? Like you want to get a kind of swath of what's there.
Rosemary:Yeah, if you're seeing multiple species, but we would encourage you to, you know, to make sure to properly preserve anything that you're gonna send in. So, you know, putting it in alcohol or something of that nature and not, you know, sending us just a bag is not useful because they won't be in good shape by the time they get to us.
Michelle:I will make sure to include all of these websites that we're listing in our show notes so that listeners have easy access to these resources if they haven't already identified them themselves. So make sure you take a look there. So I I think what else I heard you say, Dr. Sifford, in that last segment is we're not recommend recommending prophylactic treatment at this time. I think, especially in our our our flocks and herds that are you know out on range or folks that are dealing with captive cervids, there's a lot of call for some kind of preventative recommendations. Is there anything that that we know is going to be effective at preventing this drug-wise at this time? What is the USDA's position on that?
Rosemary:Yeah, I mean, so again, you you know, the the the FDA products that they that they you know have available that are are you know could be used to treat similar conditions as as they've mentioned would be the recommended for extra label use. But but I think from our perspective, the most important piece again is the surveillance. And I and for folks who aren't seeing their animals, you know, on a regular basis, or it might be difficult for them to be doing that really close look. You know, I think in our experience, these are the kinds of wounds that you're more likely to notice. I mean, you might not notice it right away when the first fly appears, but they definitely have a different smell and appearance because they tend to be growing rather than shrinking, and and you'll and you tend to notice the the change in the animal because they do you know have concerns about the their ability to keep going because the the larvae are eating living tissue and it and it expands rather rapidly. We do have surveillance along the southern border of the United States underway that involves trapping for flies. We're doing that out of an abundance of caution because we are working closely with Mexico and understand their surveillance scheme and our and are tracking the cases that they see. But out of an abundance of caution, we've also placed traps along our southern border to monitor and make sure that we don't see any flies making their way to the United States. We're also working very closely again, using our tick riders to look for any stray animals or wildlife that might cross the border with an infestation. So we have a high level of confidence that we won't have an incursion come across that we don't identify early. And probably the most important then other factor is those animals that might be imported through other means such as airports. And so, you know, again, if if a person is returning with a pit and they notice an unusual wound returning from a screw worm-affected country, it'd be really important for them to see their accredited veterinarian with that animal. And and so, in terms of preventative treatments, there it is very limited. And as you guys are all too aware, there are fewer FDA approved approved drugs for from the species that that you guys are working with than for a lot of other species. And then, as we mentioned, none of those are currently labeled for New World Screwworm. But FDA has you know clarified some of the extra label drug use requirements, which would be important in this case. And so we would definitely encourage veterinarians to seek guidance from FDA or Fared or other sources on extra label drug use for those animals. But also, importantly, it's really important that. That you know that producers are doing good wound care, whether that is a an accidental wound or say a recovering surgical incision or something of that nature, because the the good wound care is would be really important for the early identification and then for making sure that you know we don't set up a situation that attracts the screwworm flaws.
Sarah:And I would say not many veterinarians are usually part of that process. You know, most producers are pretty good at doing their own wound care. And I mean, they might advise, but in my personal practice, I have a lot of pets, pet livestock for each animals and stuff like that. So I do, you know, kind of advise about that. And I have some heritage farms where we see like fly strike on their sheep because they're not tail dogging and stuff like that. So yeah, I think that's good for all of us to hear to be extra conscientious about wounds for sure when this is on the horizon. So moving forward, you know, this is gonna be an ongoing conversation. Obviously, it's just starting, and hopefully it isn't actually. Hopefully, the conversation dies and we don't talk about it and we're not worried about it anymore. I will say I I was talking to a new vet earlier today, and she's only been out of vet school maybe a year, and they were told that it is here that there has been cases in Florida when she was in vet school, which maybe is not true, but is concerning that people are, you know, that we're getting different storylines. I guess that kind of is concerning that we're not all on the same page. So, you know, I don't know if it's gossip or exactly what it is, but when she said that I wasn't like, no, no, no, it's not a kind of day. She's like, that's so we were told, and I was just like, okay, so how do we stay current on what's going on? And you know, we had kind of talked about the FDA, and I know you guys have a good page, but and obviously ASRP, we will do what we can to keep our members informed as we learn things. But do you have any specific recommendations?
Rosemary:Yeah, I mean, so we are we are definitely working to make sure that we update our website regularly and put new information. And as a matter of fact, we have recently updated our response guide and have and placed that there. So that might be something that veterinarians are interested in. But just to say a word about the you know, the presence in the United States. So I'm sure that that recent graduate was referring to the fact that we did have an isolated outbreak in the Florida Keys around 2017. And so that outbreak was identified by a pet owner who brought their animal in for examination when they had an unusual wound. And then it we were able to understand that it had also a population had established itself in the in some of the keys and was affecting the key deer. So we used the sterile insects to eradicate that population, but but that did take about six to seven months from the time that we identified that there was a population that existed there until that we were able to eradicate it. And during that time, in releasing the sterile insects, we also did surveillance and and monitoring and then continued that afterwards to make sure we had gotten all the flies. And we also do occasionally have, it's not terribly uncommon for us to have an animal or a person that arrives to the United States from an affected country arrive with a wound that that is affected. You might have seen earlier this week the announcement that we did have a human case that that came to the United States. And over the years, we see a few, not very many, but either pets or horses that arrive with wounds that are affected. That's one of the reasons that we, you know, we ask that folks stay vigilant and monitor and bring things to their veterinarian because when those kinds of cases happen, once the veterinarian has identified the situation and they send us samples, we will do very similar activities. You know, we would work with that veterinarian to talk with the owner about where the pet or horse, if it happens to be a horse, has been, and then do trapping or other activities in that area to make sure that there isn't a population that has managed to get established there.
Sarah:Well, obviously that's scary, but it also like teaches us how to deal with it, right? And helps us know what works and helps us be prepared if something you know bigger comes along. So that's that's interesting, good to know for sure. Especially for those of us that love to travel and like spend lots of time in South America and all those places. Yeah, don't ignore those wounds when you when you get back from your Chilean vacation for sure.
Rosemary:Yeah, absolutely. Well, and and you know, international travel is more and more common, and international travel with pets is more and more common. So, you know, that definitely is something important. Yes, don't ignore those wounds. That's great advice. And we will we will definitely keep our website updated, you know, as we receive more information, as we do more work for preparedness here in the United States, we will we will continue to add more information to our website and tools for for veterinarians, like the the webinars that we recently posted to give veterinarians a little more in-depth into this situation.
Sarah:Awesome, awesome. And then, yeah, that kind of leads right into my last question, which was how do we get more training on the disease just so you know we are as prepared as possible to be helpful, both in large and small animal. I mean, a ton of us that are large animal are mixed and see, you know, small animals also.
Rosemary:Yeah, and yeah, as I just mentioned, we we've just recently recorded a webinar and posted it on our website that goes into a good bit of detail. We also have updated our veterinary accreditation training module on New World Screwworm. And so if you're up for accreditation renewal, it's a great module to take at this time. And if you're not, you can take modules at any time. You don't have to just take them when you're up for renewal, but but we have updated that one and and put some additional information in it as well.
Sarah:That's good to know. We some of us get tired of doing the same modules every time we need to. You're like, uh, I always do the small ruminant one, I always do the same ones. And not that they aren't changed periodically, but it's good to know there's something new out there. And I mean, you have to do it anyway, so you might as well, you know, get your knowledge. So awesome, great. Can you tell us a is there are there countries where it's like known to be prevalent just for people who are traveling there? So they kind of have a heads up to uh, you know, just to be prepared.
Rosemary:So, yeah, so the New World screw worm exists and is considered endemic in South America and and in the Caribbean. So a lot of the places that that you know we tend to go on vacation do have endemic populations. Central America had been free until this current outbreak, but but most Central American countries are experiencing cases in this current outbreak. And as we've been talking about, you know, all the way up to uh Mexico.
Sarah:So all those beach places we love, right? Haiti, Dominican Republic, all those beautiful places you go on the cruise ships. Okay, good to know. Good to know.
Rosemary:Yeah, yeah, yeah. So yeah. So when you come back from your cruise, you know, if you're feeling something unusual or seeing a wound, do something that you are thinking that it should not do. For people, definitely important to see the physician, and for you know, for any pets or other animals to the veterinarian.
Sarah:Yes, don't show me your wound. I don't want to see your wound, people. I only want to see your pets, but people love to show their veterinarians their own medical issues. All right. Is there anything else that you would like to add on this topic? I mean, it is like it's such a weird line between that doesn't seem like a big deal to wow, that could really be a big deal. You know what I mean?
Rosemary:Yep, yep. And I think, I mean, I think it's like a lot of the other things that that you know that we work with in our space. It's we spend a lot of time trying to make nothing happen. And that's exactly where we are in this space as well, doing a lot of preparedness work and trying to make sure that nothing happens because we're able to keep the new world screw arm out of the United States. So yeah, another place to try to make sure that nothing happens.
Sarah:That's like half of a veterinarian's job between vaccines and prevention and all of that, making nothing happen. I like that. I'm gonna use that. All right. Well, unfortunately, Dr. Buckley had to step out, but we will go ahead and thank Dr. Sifford for taking the time to speak to us. And I hope this podcast kind of opens our eyes a little bit and gets us thinking and on the lookout for these things. And we will definitely put all these websites into the into the notes. And obviously, most of our large animal veterinarians are USCA accredited. So the next time you have to do those hours of CE before you can re-up to write all your CVIs, maybe think about doing the screwworm one. So thanks again so much. And yeah, good luck keeping this, keeping nothing happening.
Rosemary:All right. Thank you for your time. Nice to talk to you.
