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University of Minnesota Extension Swine team gives research updates through podcasts.
Sarah Schieck Boelke:
Hello and welcome to Minnesota Swine and U podcast series a University of Minnesota Extension Swine program. Today's podcast is a research update on African Swine Fever preparedness for the US.
My name is Sarah Schieck Boelke, your host, and I'm a Swine Extension Educator with the University of Minnesota. Joining me today is Rachel Schambow, who is a postdoctoral researcher in the University of Minnesota's Center for Animal Health and Food Safety
To get us started today, Rachel, would you introduce yourself? And kind of yeah, briefly explain who you work with and what you do.
Rachel Schambow:
Yeah, thanks so much, Sarah, for having me on today. So as you said, my name is Rachel Schambow. I am a veterinarian and a veterinary epidemiologist here at the University of Minnesota Center for Animal Health and Food Safety, or CAHFS, as we call it. That’s C-A-H-F-S. CAHFS. So we are a part of the College of Veterinary Medicine. And our center really focuses on international programs and trying to connect Minnesota in the world for solutions to veterinary public health.
My work within the center focuses largely on learning more about the epidemiology of African Swine Fever, or ASF, using both quantitative and qualitative research methods. And so the work that I'll be talking about today around ASF preparedness represents the combined efforts of many, many people on our cast team, so I certainly cannot take credit for all of this work. A lot of post docs, graduate students, residents, and faculty, have helped out with this work.
Sarah Schieck Boelke:
I'm excited to learn more about your project that you have and that you'll be talking about today. So can you say specifically, what research topic will you be sharing today?
Rachel Schambow:
So I'll be sharing more about some of our recent work in the past year or 2 about ASF epidemiology and the Dominican Republic, and in the Philippines, and talking about how these experiences and the lessons that we've learned can be applied to improve our preparedness here in the United States.
Sarah Schieck Boelke:
Now I know as somebody that works within the university as well as works on projects. I know that stuff like this can't happen without funding, so are you able to share either what source or sources funded this project.
Rachel Schambow:
Yeah, absolutely and really happy to recognize these organizations. So this is a series of projects that have various sources of funding depending on the specific project. But generally we've been supported by USDA partners including APHIS, Foreign Ag Service, Ag Research Service and the Center for Epidemiology and Animal Health. That's CEAH. And also our partners at the National Pork Board and the Swine Health Information Center. So we really appreciate all of their support and the expertise that they've lended to help with these projects.
Sarah Schieck Boelke:
Thanks for sharing all those funding sources. Like you said, it's important to acknowledge them. Because yeah, a lot of the work that we do is not possible without those funding sources. So thanks for giving a shout out to them.
So next, let's get a little bit more into talking about specifics, about your research that you did. Can you give a brief introduction to this research project, and why it was a valuable project to do for the industry?
Rachel Schambow:
Yeah, of course. So as I'm sure, probably everybody that's listening to this podcast. Or most people listening to this podcast. Are already familiar with ASF remains a pretty tremendous threat to the United States. If we look at the past couple of years, outbreaks have continued to spread globally into new countries. We've seen a lot of new introductions into parts of Europe and Southeast Asia, and have also reemerged into regions where it seemed to have quieted down for a little bit. So, for example, South Korea has seen some reemergences in the past year as well.
So this really shows us that ASF is a continuing threat that is not likely to go away anytime soon, and we know that the impact to the US would be tremendous. It's been estimated in a previous study that over 50 billion dollars it could cost us across about a 10 year scenario due to those lost export markets and control measures.
And that's because, partially in the US we would apply what's called a stamping out approach. That means that we want to totally eradicate any ASF that would be in our country if it were detected, and this, you know, ultimately, would happen through a lot the total depopulation of affected herds.
There's also not still a widely approved or available vaccine for ASF, despite a lot of research and a lot of promising results so far, globally. So, the control measures that we would be able to use in the United States are largely limited to things like biosecurity, quarantine and movement controls and surveillance that would help us to detect infected herds.
So given that that's kind of our tool set. It's highly valuable that we understand how these are being used in countries that are currently affected by ASF. This way we can both help these countries to control the disease in their region, ultimately reducing the global ASF burden and apply the lessons that we learn to improve our preparedness here.
So we've been conducting a series of research projects that I'll highlight more as we talk about it that ultimately are characterizing the ASF spread and risk factors in the Dominican Republic and the Philippines. So both of these countries have been affected by ASF. So the Dominican Republic since 2021 and the Philippines since 2019.
Ultimately this work really helps us to learn what works and what doesn't work for ASF prevention and control, and interestingly, from different contexts and from a more holistic perspective that includes input from producers, veterinarians, and also that regulatory look as well. So veterinary authority or government officials.
Sarah Schieck Boelke:
As you were giving a little bit of a background, I was kind of thinking that it almost seems like for some of these countries and the work that you have done with those countries. It's almost like they're kind of like a trial run if you wanna say for us.
Rachel Schambow:
Yeah, definitely. It's definitely a great win win scenario for everyone. We get to support them and help them and share information. But they're also sharing information back. So ultimately, it's a really great partnership to you know try these things together, and really try to help solve this problem.
Sarah Schieck Boelke:
Yeah. So how did you complete this study? Or I should say studies, because it's a couple of them together, right? That you'll be talking about.
Rachel Schambow:
Yeah, so we have conducted these studies using both qualitative and quantitative approaches so qualitative projects have included things like assessing the advantages and disadvantages of various control strategies. So that's, you know, talking with producers, with veterinarians in a more systematic way and trying to understand the pros and cons. And how these types of strategies would affect them, and trying to understand the feasibility of implementing these particular mitigation measures with more of a you know, look at the field, and those veterinarians and producers.
And then the quantitative studies have included things like characterizing the occurrence of outbreaks across space and time within a country. So we call that spatial temporal analysis. And also identifying where clusters of outbreaks occur. So that's when you have multiple outbreaks occurring together in the same time and space. And then we wanna try to understand what factors are associated with the occurrences of the disease, cause that helps us to start to understand what increases or decreases your risk for ASF at an individual farm or at country level.
And then in some of these, we've also ranked the relative importance or influence of these various risk factors. So you know, these can be things like, you know. Are you swill feeding? Do you have a fence? What's your biosecurity measures that you implement? Or what protocols do you have?
We also have an ongoing project in the Dominican Republic to understand the potential use and application of point of care tests. And sometimes we call these pen side tests. So this specific project is focused on assessing both the accuracy of this test, using samples from the Dominican Republic, but then also assessing how feasible it is to implement these tests in the field, or how useful they would be on farms.
And then I'll also highlight a couple of smaller projects that we have ongoing. So we have a series of projects in the US looking at ASF surveillance, particularly the Sick Pig Program. That's testing case compatible submissions through veterinary diagnostic labs. And we're really trying to identify ways to support the program and decrease the time that it takes to detect ASF in a herd and in the US.
And then, lastly, I just wanna highlight an event that we held last year at the Leman Swine Conference, that kind of ties a lot of these projects together. So this was called Vets to Vets, and it was funded by the National Pork Board, and at this event we were able to bring vets working in ASF affected countries. So these were veterinarians that you know, we've worked with through all of these various projects and we're able to bring them here to the Leman Swine Conference to talk with us swine veterinarians about what they do to protect their herds from ASF in these infected regions, and many of the overall lessons that we learned from all these various research activities were also captured and discussed at this event. And there is a report available on our website, the CAHFS website. And I believe it was also previously highlighted in the UMN Extension Newsletter, as well.
Sarah Schieck Boelke:
Yeah, that's correct. Our June issue. I believe it was the June issue that I included it. So I should try to remember that when I post this podcast we'll put it in the show notes as well to link to those sources where folks can find more information.
Rachel Schambow:
Yeah, perfect. And then I will also add to you know, I've already thanked our sponsors and our funders, but I also want to thank all of our in-country partners and the veterinarians that we've worked with. You know. Clearly I'm listing a lot of different projects in different regions, and without those folks, you know, that would be pretty impossible. So we super appreciate all of the work and support from all of those collaborators, as well.
Sarah Schieck Boelke:
So what have been some lessons that have been learned through all different pieces, I guess, of this larger project, I'll call it, whether it's the vets to vets discussion, or some of the other stuff that this study has been doing.
Rachel Schambow:
Yeah, so there's been a lot of different lessons learned. And I'm gonna try to point out some of the key ones. From some of these projects that we've been doing so 1st off, you know, the important epidemiological drivers are basically those factors that greatly influence the spread of ASF differ somewhat by region depending on the makeup of swine production and the presence of other risk factors in that region. So, for example, in Europe, wild boars have been a huge factor for the spread and maintenance of ASF.
You know. This, though, is important to remember that these epidemiological drivers and factors are different country to country. So it's really important that we don't just, you know, copy and paste what other places are doing that we consider our own countries. You know commercial swine production makeup. You know, our own socioeconomic factors kind of all of that stuff.
However, probably the most universally important factor in the spread of ASF is human mediated factors. So ASF is a really really hardy virus, and it's easily spread through contaminated fomites, such as vehicles, movements of people, things like swill feeding. So all these human mediated factors become a really important driver for that ASF spread especially for these long distance jumps. But it also becomes an important intervention point for us.
And I just wanna highlight some of the other factors that we've identified through our work in the Philippines and the Dominican Republic. So an analysis that we did, using surveillance data from the Dominican Republic, from 2022 to 2023, we found that ASF was most commonly affecting backyard producers that had limited biosecurity and outbreaks were tending to cluster amongst neighboring backyard farms and based on the other information that was collected about these farms. It's most likely because one, they were really spatially close to each other.
And they also had shared practices or contact. So, for example, some of these farms have free, ranging pigs. They share equipment between neighboring farms, or they share a boar. So they have all of these linkages to each other. That's causing this continued disease transmission.
In the Philippines our analyses found a seasonal pattern that coincided with the rainy season, and that has been indicated in other places as well and also cultural practices around swine production. So again, emphasizing that influence and importance of human factors on ASF spread.
And they also did further analysis into the specific risk factors and identified that swill or contaminated feed, inadequate biosecurity protocols, and the movement of personnel as being the top contributors to ASF spread. And this is from the perspective of veterinarians who had extensive experience with the outbreaks.
Sarah Schieck Boelke:
Yeah, as you were talking about in some of those other countries. I know my colleague, Diane DeWitte, was able to travel to the Dominican Republic.
I think it was a farmer to farmer program. I think. She was doing some education there. And yeah, she shared stories of some of what she learned from. I don't know that she was out in the countryside as much with her project. But at least interacting with the folks that came to her for the workshops. Yeah, just talking about the differences in how they raise pigs and, like you mentioned in some of the, you know, villages or communities.
Yeah, they'll share a boar, so he'll be kind of the community boar, and with some of the practices that we do within the industry, we might gasp and say, what? But for some of these other countries. Yeah, that's what they do.
Rachel Schambow:
Yeah, it's their normal. And I think it also highlights. Again, it's important to remember, like everybody's different contexts and how these control, you know, strategies are applied, and you're kind of translating that back into what will work or potentially not work for us as well.
Sarah Schieck Boelke:
Yeah, that is good. And also I was thinking, too, here in the US I mean, we're a little bit different as well where you were talking about in Europe, how that with the wild boar, I mean, there's certainly, you know, a lot of our Southern States here in the US do have feral pig populations. So again, even within the US, I'm sure we'll have some differences. So it seems like everything that you've been able to gather will for sure help us.
So then, moving on, what have you learned about surveillance and early detection as you've been working with these other countries?
Rachel Schambow:
Yeah. So especially from our Vets to Vet, an event that we held at Leman Conference last year, we've learned the continued difficulty in the early detection of ASF. So, despite its really high mortality, ASF spreads pretty slowly in herds, and in that initial time period after that 1st introduction. Not many pigs will have clinical signs, and mortality will still be pretty low.
Also, ASF can appear very similar to common diseases like PRRS. So especially in the US where we don't have ASF yet. It might be really difficult to recognize that 1st occurrence, and we've also learned that ASF doesn't always appear in that, you know, traditional, highly acute, highly lethal form. Experiences from veterinarians and producers in the Dominican Republic, some of our collaborators, have shown and reported more of this mixed presentation, so pigs may not appear to be very sick. Mortality may be low to moderate, and in some cases, you know, they report. Oh, we gave the pigs antibiotics, and then they recovered, or appeared to recover afterwards. So that can really confuse you as to what you're seeing, and may not raise that suspicion of ASF.
Interestingly, you know, these anecdotal reports were corroborated by experimental studies that were done with the ASF strain by the Ag Research Service, where they experimentally inoculated pigs and those pigs had again that mixed presentation. So they weren't all, you know, getting that super high fever. Hemorrhagic signs and dying in a few days. Some of them kind of had more of this, you know, sub acute even potentially chronic presentation. So it's important to remember that, you know, depending on different contexts. The disease might not look, you know, like it does in the textbook. So we definitely need to stay vigilant there.
And from Vets to Vets we learned that vets and producers in affected countries have implemented pretty stringent measures for early detection. So, for example, in sow farms. In affected countries. They will have workers walk the pens, you know, at least once to twice a day, doing daily observation of sows, looking for things like, you know.
Does the sow have a fever? Does she appear off? Is she eating? Is she lethargic? you know, even if they get kind of a sense of any of those things. They just remove her even before you know, applying diagnostic tests, because for them, you know, in these regions where, you know, it's important to note that they can do partial depopulation for them. It's worth taking that sow out to catch that infection early rather than waiting, you know, to make sure that it's ASF or see if it's something else. They just don't take risk there. So they're applying these super super stringent daily observation protocols
Also our work in various places really highlights the importance of passive surveillance for the early detection component of ASF. so passive surveillance refers to observer initiated reporting. So that's basically detection by the producers and veterinarians who detect suspicious clinical signs and new necropsy findings and then make a report to a government or veterinary authority. It's gonna be really important for farms to identify a system that works for them to improve their detection of clinical signs and necropsy findings.
And there have been some projects and methods out there doing things like using statistical methods that can use production data to identify anomalously high mortalities or abortions. But I think it's important to remember that, you know, because of ASF slow spread and also the limitations of entering data into computer system, right? That creates a time delay.
Overall. That could be a little delayed for early detection. We, I remember, from the Vets to Vets events. Them saying, you know, it can take up to 6 months for you to really notice that abortions are high enough and heard that, you know it's above kind of that baseline or background.
So those kinds of tools are really really interesting, and I think they will be super helpful. But it's always important to remember that training personnel to recognize and report suspicious signs and necropsy findings on that daily basis. That's gonna really be the, you know, the core key element to early ASF detection.
Sarah Schieck Boelke:
Yeah, it sounds like it, especially when you said it can look like, you know, some of the other diseases that we have, you know, fairly regular in the industry. So talking about ASF detection, what can you share about your work on the use of point of care diagnostic tests?
Rachel Schambow:
Yeah. So our work on characterizing point of care test is still ongoing. This is being done in the Dominican Republic using swine samples there. And in, you know, we, even though that work is still ongoing to understand the accuracy, we have been able to take a look at some of that, you know, feasibility and fitness for purpose. So one of our post docs, Sylvester Ochwell, is leading this work, and he does have one paper out. That's kind of describing the attributes that are important for a pen side or a field test.
And you know, when we use that framework to think about all of these different point of care tests that are coming out. For, ASF you know, we feel that these tests could support the early detection of diseases. or in the case of an ASF control area, so an ASF control area would be a region where you have an ASF detection and you have geographically around that control measures applied. In that case we might end up in a situation where you have many farms, and you know, we might have limited staff or resources, so they could be helpful in trying to prioritize which herds need further confirmatory testing. You're saying, Hey, I need you to come out and test this herd. You know, as soon as possible.
Also in resource limited settings or countries, these tests might be particularly advantageous there, because they can be pretty cheap, and they can be a versatile alternative to more expensive testing.
However, I do wanna note a couple of caveats to this, and we've kind of learned this through using the systems. 1st off, these types of tests have not been approved yet for ASF diagnosis in the United States, so as of today. The only available test for ASF. Here are those that are conducted at official VDLs. So it's not something that you know at this moment could be used by veterinarians or producers in the field. I believe there are, though, some for domestic diseases that are being developed as well. So you know, this next section will still kind of apply to those, too.
And that's that. Not all point of care tests have the same fitness or feasibility to be implemented on a farm or in all farm settings. So some actually require, you know, personnel, to be trained in pretty extensive lab techniques. You know, things like being able to pipette small volumes, which sounds very simple when you say it out loud. But for those who've had to do it's actually quite tricky and requires some practice and some training. Other systems are essentially kind of at home or you know, at farm PCR machines that can be mobile and go on the road. And so those actually still require pretty expensive equipment as well.
So they, you know, can be really complex and require that technical expertise to implement, and not all situations or farms might have that, or that might not be advantageous for all farms. Additionally, these tests can have a greatly reduced ability to detect positive animals. So they have a potentially lower sensitivity than our in lab tests like our traditional PCR, that we'd use with whole blood that you'd send to an official VDL, so they might not be as accurate as those, and they also can have a higher rate of false positives as well, so those might make them, you know, not so much a suitable alternative.
So ultimately the decision of implementing these types of tests, you know, if they were approved to be used, it would really need to be considered by the farm or farm system and their veterinarian on a case by case basis. But I would also mention to like ultimately, it's important that the test results be interpreted by someone who understands the context around these tests. So understanding their accuracy and their limitations, as well.
Sarah Schieck Boelke:
And I know that I've heard you know about work that's being done on, you know, trying to find other tests to help us confirm African swine fever, so interesting to hear about some of these other things.
So based off of your results of these different projects, what conclusions can be made from the research so far, because I know you've mentioned it's still ongoing.
Rachel Schambow:
Yeah, still ongoing. But definitely, there are some takeaways. So far, so probably the biggest takeaway is that ASF control is very complicated and requires extensive coordination between public and private partners. It's really important that the private industry and the public veterinary authority are aligned, and that everybody understands their roles and responsibilities toward ASF control.
So continuing that dialogue between and amongst industry and regulatory officials is going to be really important for the US. Second, the more that we can do in advance the better. Especially talking with the folks that went to the Vets to Vets event, you know, they said time and time again, that you know, when that ASF introduction occurs, everyone kind of is really shifting into that emergency response mode. And we are really really limited on time, personnel and resources.
So there's not really going to be a lot of time to test out new strategies. And also there's really not a lot of time for decision making. So, having that plan in place for your farm in advance will help you to be better prepared if control measures, like movement, restrictions, quarantine or surveillance requirements were to occur.
And then, finally, again, I'm emphasizing what I said before, human factors really are the biggest concern for ASF spread, and while this is a really complex issue, and it doesn't have easy fixes. Necessarily, it also does represent a great opportunity in some ways, because it is something that we can affect through various policies and outreach strategies and from the individual producer perspective. I like to think that this means you have a lot of control over protecting your own farm through the choices you make about biosecurity and surveillance, and how you try to implement those.
Sarah Schieck Boelke:
Good. Your one point sticks out in my mind about the one you know. Be prepared upfront. Because, yeah, when and if we get a foreign animal disease here in the US. That affects our pig population.
Yeah, there's not going to be a lot of time to come up with either enhanced biosecurity protocols which are part of like Secure Pork Supply or some of those other things. Yeah, like you said, we're gonna be in emergency response mode. So we basically need to have that stuff in place. And then. Now, we can implement it. So good points.
So why are the results you shared important takeaways from your study?
Rachel Schambow:
So these are important because overall again, they're really highlighting that complexity around ASF prevention and eradication. So you know, past experiences and current experiences with ASF, you know, have shown that, like, when that introduction occurs, eradication is not always a short term goal. So in past global outbreaks of ASF in the sixties and the seventies.
It took about 30 years of combined effort for Portugal and Spain to fully eradicate ASF. Another example, you know the Dominican Republic, and Haiti had ASF also through that series of global outbreaks.
And their response was to depopulate the entire island. And I think by today's standards that would seem like quite a severe response. But that was their way to, you know, get to total eradication. So it's certainly not a simple solution. Once you get ASF and in the current outbreaks only the Czech Republic and Belgium have self declared ASF freedom after their initial introductions, and it is important to remember that they only had cases in wild boar, and it did not reach their domestic swine population, and in 2022 it was redetected again in the Czech Republic. So you know, when you are in a region where you have ASF surrounding you, it's really difficult to stay ASF free. So really the best thing that the Us can do is to focus on keeping ASF out, continuing to do that and continuing to work with and support our international partners in reducing ASF's impact. So this will both help us to again reduce the global ASF burden and help us to learn from what's being done in those affected countries.
Sarah Schieck Boelke:
So to wrap up our discussion here, Rachel, are there any closing remarks that you would like to make that either? You wanna remind us of points you made already. Or maybe it's something that comes to mind that you haven't talked about yet.
Rachel Schambow:
Yeah, so I do. Wanna validate that feeling of ASF fatigue. I think that can be a really real factor for producers and veterinarians in the field, especially considering right the many, many competing priorities that swine producers, veterinarians, our rural communities have. So sometimes ASF doesn't feel like top of the list, but unfortunately we can't predict with certainty if or when an ASF introduction could occur.
So I guess I would encourage producers and veterinarians to really kind of identify their most critical needs and try to apply meaningful changes in biosecurity and surveillance things that you know you could do now to improve your preparedness, like, you know you already mentioned Sarah, like having that Secure Pork Supply plan. Having that preparedness plan in place. Maybe it's doing some training for your staff or kind of assessing what your needs are. You might even find that these can help you control and endemic diseases to like PRRS, so it can be a bit of a win win in that scenario.
And then the last point I'll make is just, you know, to let folks know where to find us. So if you want more information on our work at CAHFS, you can visit the CAHFS website. So if you just Google UMN CAHFS, and you'll find us right there. We hope to hold more events to you in the future similar to what we did with Vets to Vets last year that allow producers and veterinarians to learn more about ASF control and to give you the ability to give input on the development of new prevention and control strategies. And finally, I just wanna say, thank you again to all of our collaborators and funders for all of their cooperation and support, and of course, recognize all of our team members from CAHFS for all of their really hard work on these projects, so none of this would have been possible without all of those folks.
And of course I wanna say thank you to you as well, Sarah, for having me on to talk about this today.
Sarah Schieck Boelke:
Yeah, you're welcome.
Like I mentioned as we were chatting before we started to record. Yeah, this is one of the if you wanna say Extension deliverables to help get in valuable information that I mean, like you and others are doing in terms of research and preparedness, that we need to get out to the rest of the industry so that they know about it. So thank you for your time in sharing with us the African swine fever prevention and control that you had and others have been working on.
And I will also make note about the CAHFS website in the show notes. So when folks listen to the podcast they'll be able to find that link, too.
And thank you to everyone who listens to this University of Minnesota Swine & U podcast this has been Sarah Schieck Boelke, Swine Extension Educator, along with Rachel Schambow, Post Doctoral Researcher in the University of Minnesota Center for Animal Health and Food Safety.
To further connect with the University of Minnesota Swine Extension please visit our swine specific web pages on the University of Minnesota Extensions website at www.extension.edu/swine and on those pages you'll find connections to our blog as well as our Facebook page.
To learn about research being done by our swine faculty in veterinary medicine, please visit their Swine in Minnesota blog at www.umnswinenews.com.