Minnesota's Swine & U

Sarah Schieck Boelke:
Hello and welcome to Minnesota's Swine and U Podcast series, a Minnesota Extension Swine program. Today's Podcast is a project Update on laboratory surveillance for African and Classical Swine Fevers in the U.S.

My name is Sarah Schieck Boelke, your host, and I'm a swine extension educator with the University of Minnesota.

Joining me again today is Dr. Rachel Schambow, who is a researcher in the University of Minnesota's Center for Animal Health and Food Safety.

Welcome, Rachel.

Rachel Schambow:
Thank you, Sarah. Thanks for having me today.

Sarah Schieck Boelke:
To get us started, I know I've had you on a podcast previously, but just in case, folks have not listened to that podcast, would you just take a brief moment to introduce yourself?

Rachel Schambow:
Yeah. I am a researcher primarily in veterinary epidemiology at the University of Minnesota Center for Animal Health and Food Safety. We're a part of the College of Veterinary Medicine, and I primarily work on foreign animal disease research, like African swine fever.

Sarah Schieck Boelke:
I briefly shared, I guess, the title for the podcast but can you further explain what topic will you be sharing with us today?

Rachel Schambow:
So I'm going to be talking about an analysis that we did of USDA's sick pig surveillance component at the Iowa State University and University of Minnesota Veterinary Diagnostic Laboratories, and I might say, VDL for that throughout. So if I say VDL, I mean veterinary diagnostic laboratories
And I'll be talking about also that surveillance program in general, kind of how it works, and how producers and veterinarians can participate in it and support surveillance for ASF and CSF.

Sarah Schieck Boelke:
Yeah, that will be good because like you mentioned, maybe some folks aren't aware of the surveillance. So yeah, we can also try and educate them, too, about the program.

Before we get to you further explaining the analysis that you did. How was this project funded?

Rachel Schambow:
So I'd like to thank the USDA Center for Epidemiology and Animal Health for funding this project. And I also want to recognize both Iowa State University and University of Minnesota, Diagnostic Labs for collaborating with us and all of their support. With this project.

Sarah Schieck Boelke:
Thank you for sharing the funding source and the collaborators.

So before you explain how you analyzed USDA's sick pig surveillance program, can you explain what that program is exactly for anyone that may be unaware?

Rachel Schambow:
Yep. So USDA runs a pretty comprehensive surveillance program for both African and Classical Swine Fevers. So ASF and CSF is how we typically refer to those with the acronyms. Those are both two really important foreign animal diseases that we don't currently have in the U.S. But would cause really severe impacts both economically and to animal health if they were ever introduced.

So USDA operates the surveillance program and one of its components is what we call the Sick Pig Surveillance program at veterinary diagnostic laboratories. Sometimes we shorthand this to Sick Pig VDL component.

How this component works is that regular submissions that are sent in by producers or veterinarians from sick pigs in the U.S can also be tested for ASF and CSF if they meet some specific eligibility criteria, and they go to a lab that's approved to conduct this type of surveillance, such as UMN or ISU. Both operate this component.

To be eligible, a submission has to first have an approved sample type. Those include currently for this component spleen, spleen swabs, lymph nodes, tonsils, whole blood or whole blood swabs. They also need to have a history, clinical signs, or necropsy findings that are consistent with ASF or CSF. and they need to have a premise ID or a PIN, or a complete address listed with a submission.

And all of this testing for ASF and CSF is done at no cost to producers or veterinarians. It's all funded by the USDA.
This is a really valuable type of surveillance, because it uses a risk-based approach of targeting sick pigs. That really improves our capacity for early detection, and it also really helps support our claims of being free of ASF and CSF, when we get negative results.

Sarah Schieck Boelke:
Thank you for explaining the surveillance program.

Can you give a brief introduction to the analysis you conducted when you analyzed it, explaining why was it a valuable project to do?

Rachel Schambow:
Yeah, so there has been some evaluation of this component in the past. But implementation at specific VDLs hasn't been assessed yet. Such as how well the pigs that we test for ASF and CSF represent the general population of swine cases in the U.S.

So our research question was to evaluate the characteristics of ASF and CSF. Tested cases compared to general swine submissions at two VDLs that operate this program, the Iowa State University and the University of Minnesota diagnostic labs to really help us understand how well this component is capturing the swine population and ultimately to identify any areas that we can support with targeted education and outreach.

Sarah Schieck Boelke:
How did you complete the analysis of the USDA sick pig surveillance?

Rachel Schambow:
So we used a mixed methods approach. So that means we used both quantitative and qualitative methods in this project. So first, we did a quantitative analysis of the VDL data from UMN and ISU. And then we held a workshop with swine stakeholders to help us interpret those findings and discuss ways that the surveillance component could be supported or improved.

So we received and analyzed about 2 years of data that covered about 2022 to 2024 from both labs, and all the data that we had was de-identified. So, for example, any identifying information was replaced with generic ids. So farm one farm 2 vet. One vet. 2. So that way we're protecting client confidentiality.

The data that we received was then descriptively analyzed. We compared between cases that were tested for ASF and CSF and those that weren't. So for example, we looked at a lot of different factors like the state of origin, the types of specimens that were recorded on a case, the type of pathogens that they were tested for, age, production type and lots of other factors and I'll just be highlighting some of those today when I'll be talking about the results. I'll be referring to tissue cases here when I say tissue cases. I specifically mean those that were necropsy or histopathology, because basically, those are the ones that come in with tissues and would be potentially eligible for ASF and CSF testing as opposed to samples like serum or oral fluids, which are not approved under this surveillance component.
So after we did this quantitative analysis, we then discussed these preliminary results with a group of swine stakeholders at the 2024 Leman Swine Conference, and that group included veterinarians, producers, outreach and extension specialists, diagnostic Lab staff and USDA staff.

Sarah Schieck Boelke:
Interesting to hear that. Yeah, you not only analyze the data, but then you talk to stakeholders, to help you interpret that.

So what were the results of your analysis? What did you find?

Rachel Schambow:
So overall both labs appear to be implementing this surveillance component at a high level.So from about 2022 to 2024 University of Minnesota lab tested about 1,500 cases per ASF and CSF, which was about 56% of the tissue cases that they received during that time period, and then ISU tested about just under 7,000 cases for ASF and CSF, which was about 33% of the tissue cases that they received but after calculating that we next looked at the proportion of tissue cases that had approved sample types recorded with them, which is probably the most important criteria, one of the most important criteria for eligibility, for the surveillance component.

Sarah Schieck Boelke:
Are you able to remind listeners? What is an approved sample type again? So as you talk about that, yeah, what are some of those samples that might be included in this surveillance.

Rachel Schambow:
Yeah, great question. So when I say an approved sample type, generally, I'm referring to those sample types that Usda has approved and validated for ASF and CSF testing specifically for the sick pig, Vdl component. Those currently include spleen and spleen swabs, lymph nodes, tonsils, full blood and whole blood swabs.

So, considering just those sample types, when we looked closer at the cases that had one or more of those recorded with them, about 88% of those that had an approved sample type were tested at the University of Minnesota Lab, and about 64% were tested at Iowa State University Lab, and most of the ASF, CSF testing at both labs was done using spleen samples and both labs had very few recorded tonsils, lymph nodes, or whole blood samples that were submitted. With these types of cases.

However, we don't actually get a full list of tissues that are submitted with each case. So we can't determine the exact percentage of cases that had an approved sample type with them. So that's an important limitation of our analysis to keep in mind.

Sarah Schieck Boelke:
And was there a difference in where tested and non-tested cases came from at all?

Rachel Schambow:
So we looked at this on a state level, and for the most part they were really similar. So University of Minnesota received submissions overall from 35 different States, and they had ASF, CSF tested cases from 18 different States for both the overall submissions and those that were tested for ASF and CSF. It was mainly Minnesota, Iowa, and Oklahoma for Isu. They received submissions from 46 different States overall, and they had tested cases for ASF. And CSF from 39 different States. Again, mainly Iowa, North Carolina, and Indiana.

Proportionally, those top 6 submitting States had about 25 to 40% of their submitted tissue cases ruled out for ASF or CSF. And really overall when we looked at a map of testing, you know, for all the cases or a map of where all of the cases came from versus those that were tested for ASF and CSF. There was very large overlap where those large commercial populations appear to be so kind of suggesting that those you know commercial states are really well captured by this surveillance component at the labs.

Sarah Schieck Boelke:
That is reassuring to hear of the samples that were being tested. What types of cases were they? Because, if I understand correctly, for the surveillance program. The samples were coming in for something else, but resembled African swine, fever, or classical swine fever. Is that correct?

Rachel Schambow:
Yeah, exactly. So this surveillance component is really intended to test for ASF and CSF, in sick pig cases where the producer or the veterinarian doesn't suspect a foreign animal disease, right? They're suspecting something like Pers.

But we know that some of those types of pathogens can cause similar clinical signs. So pers erysipelas or salmon nellosis, for example, amongst others, they can share similar clinical signs and presentations as foreign animal diseases like ASF or CSF.

So having this program in place is like having that extra safety net just to, you know. Make sure we're, you know, we're pretty sure that it's not this. But we have this kind of operating in the background just to do that double check.

So with the data that we had, we were able to see what types of pathogens. Each case was tested for, and then we compared that to which also had ASF and CSF ruled out. There was a lot of variability here. So I'll just highlight that pers testing was, as we expected, by far the most common just overall.

So like I said, Pers virus can be a differential for ASF and CSF, they can share similar clinical signs. And then, considering just those that were tested for Pers at umn and Isu, about 20% and 40% of tissue cases tested for Pers were also tested for ASF and CSF.

Sarah Schieck Boelke:
I think that's a good point that you made that some of the common diseases that the industry experiences do have some similar signs, such as our African swine fever and classical swine fever. I think that's good to point out. And like you said, Yeah, the surveillance program here seems like a nice, if you want to say, like a safety net, to be able to rule out those foreign animal diseases.

Rachel Schambow:
Yeah, exactly.

Sarah Schieck Boelke:
Were you able to see any differences in testing between farm or pig specific factors like age or farm type at all?

Rachel Schambow:
So we did see some slight differences. So this type of data isn't always available for every case, but for those that we were able to see it.

Rachel Schambow:
The vast majority of tissue cases overall came from nursery and finishing pigs and overall. There were relatively few submissions from adult pig groups, so sows or boars. When we talked to our workshop participants, they confirmed that that was to be expected, and is consistent with the makeup of the industry. So really no concerns there.

When we analyzed this further submissions that were from pigs under a year of age were nearly twice as likely to be tested for ASF and CSF. Compared to those cases that came from older pigs. Again, we talked to our workshop participants about this, and they discussed that they typically see increased disease incidence in those younger production groups, and also that tissue collection is just more difficult to do in adult pigs. So non-tissue samples are preferred. So things like oral fluids and serum are overall. They really weren't surprised by that.

And additionally, it seems that, you know, while we're capturing a lot of the commercial swine pretty well by this components, we're not getting as many submissions. And really there's very few overall from other types of farms or pig owners so like hobbies or show herds.

Sarah Schieck Boelke:
I was on another call this morning, not talking about this, but talking about our foreign animal disease preparedness. And that was you referred to feeling that maybe the hobby and the show pigs were not well represented. I think that's something in all of the things, especially like some of the educational pieces that I'm doing. Yeah. Trying to reach those folks isn't always as easy as our commercial herds. So yeah, not surprising. That in your analysis. There wasn't that many submissions from those groups.

Rachel Schambow:
Yeah. And this was something that we were able to take to again to our workshop participants and ask them.

So you know, when we did the workshop. We kind of showed them all of these preliminary results, and they felt again that it was running really well in the commercial swine population. They felt that given industry practices, financial constraints, other concerns that trying to increase testing, sampling, and testing from those groups would be kind of limited gains there. But to your point. One of the ideas that came out from that workshop was about, how do we reach? You know those other types of swine farmers and pig owners, and one of the ideas was through education of mixed animal veterinarians. So, for example, particularly in some of these non swine dense regions, where there's less commercial swine or high intensive commercial swine.

You know, we don't necessarily have as many swine specific vets. And also we just generally have a lot of food, animal vet shortages going on. So what we think we're going to have happen, or what we might already have happen is that more and more small and mixed animal vets that don't necessarily have that specific swine training might be seeing swine clients, but because they don't have that specific swine training. They might not be aware

That these swine for enamel diseases are a concern, and they might not know what to keep an eye out for or what to look for. So one of the discussions we had at that workshop was that training those types of vets could be a really valuable way to help us reach those populations, and conduct ASF and surveillance in those groups of pigs.

Sarah Schieck Boelke:
Yeah, those are good points. That was something I was gonna ask you, as well as yeah. You think? Maybe with the smaller size herds, and or maybe our show pigs. Maybe they could be seen by veterinarians that are not. You know, your swine specific, but more of like a mixed practice, or either just focus on large animals. And yeah, maybe maybe we just haven't reached that group. Very well, in educating them about some of this stuff so good, good additional points there moving on. What were the results of your analysis?

So Rachel based off your results. What overall conclusions can be made from the analysis of the surveillance programs for Asf and classical swine fever.

Rachel Schambow:
So overall, we feel that you know it appears that the sick pig surveillance component is being implemented at a high level at both University of Minnesota and Iowa State University Veterinary Diagnostic Labs, and that the majority of cases that come in with compatible tissues, at least that we can see have compatible tissues are being rolled out for Asf. And Csf.

It also appears that the component is operating well for the commercial swine industry, but that we could help improve submission and testing. Amongst other swine groups and pig owners.

Sarah Schieck Boelke:
The next. Why are the results you shared important takeaways from your analysis?

Rachel Schambow:
So these results help us to demonstrate the effectiveness of the sick pig component, which is important both for early detection of these diseases, and also for demonstrating that we are free of Asf and Csf to our trading partners. So when we can show that these programs are working well, it increases confidence for our trading partners, which really helps support exports and other things as well.

Again, not, you know, not just the early detection, but those negative results are very, very valuable as well. And we also have identified some specific areas that we can focus on with some targeted outreach and education with the hope of increasing producers and veterinarians. Awareness of this really valuable surveillance component.

Sarah Schieck Boelke:
And I'm sure, too, not only does it help add confidence, and also see where there could be some areas of improvement, but I'm sure, too, for the funding source of this program. They also can help answer the question as to how those dollars are being used.

Rachel Schambow:
Yeah, exactly. And I think all of the type of information that we gather through this type of work really helps the folks at Usda and other parts of veterinary services. You know, when they're changing the program, updating the program, you know, having that, you know, such as input from the workshop like those kinds of things really help them when they go through and make those updates.

Sarah Schieck Boelke:
So to wrap up our discussion here today. Are there any closing remarks that you would like to make?

Rachel Schambow:
Yeah. So the last thing that I want to leave the listeners with is just to let producers and veterinarians know how they can participate in the surveillance component.

So any us swine are eligible can be large. Small farms, commercial, non-commercial. They just need to originate from the United States when you're submitting samples to diagnose sick pigs you might consider, including an eligible sample type for ASF and CSF testing. So in particular, veterinarians should consider submitting a compatible sample with their case. If they see signs, including morbidity or mortality, above a farm's regular level, especially things like sudden death.

red or purple, blotchy skin, hemorrhagic symptoms or organs, large spleen or abortions in pregnant sows. Remember, though, if you ever do suspect a foreign animal disease, contact your state or federal animal health official immediately.

and then talking more about the eligible sample types. Again, I want to remind you that, according to Usda for this component, those are currently spleen and spleen swabs, tonsil, lymph nodes, and whole blood and whole blood swabs.

Then, when you're filling out the submission form for the case, include any relevant clinical signs or history. So, for example, if pigs are dying, you might just write high mortality.

even if you don't include this information on the form, the pathologist or diagnostician that receives your case at the lab, will still review the entire case and look at things like the pathology findings and make that decision of whether it should be tested or not, because ultimately it's the decision of the pathologist or diagnostician whether it should be conducted for Asf Csf testing

also on the submission form. Make sure you include your premise. Id number, if you have one. Otherwise a complete address. So a Po box doesn't work for this. You do have to have a complete address with the submission or your PIN. And then, finally, you just submit it to an approved veterinary diagnostic laboratory that operates this program, and you can find a list of those on Usda's website. So usually, I just search for like

veterinary diagnostic labs approved for ASF surveillance. And usually that pulls it up.
And again, staff that receive your sick pig case will review it, and then make that determination whether it'll be tested for ASF and CSF as well. And then finally, Asf CSF testing is free for producers and veterinarians. So it doesn't cost anything. All of those costs are covered by Usda again, having that extra safety net just to make sure we don't think it's ASF. We don't think it's CSF. But kind of just having that extra layer of protection. There.

Sarah Schieck Boelke:
Great. I thought you had some really good reminders there, Well, thank you, Rachel, for sharing your project with us on African swine fever and classical swine fever, sick pig, surveillance component

and thank you to those listening to the University of Minnesota swine podcast. Once again, this is Sarah Sheikh, Belke, swine extension educator, along with Dr. Rachel Chambeau, Researcher in the University of Minnesota Center for Animal Health and Food Safety.

To further connect with Minnesota Swine Extension. Please visit the swine specific web pages on University of Minnesota Extension's website at I'll say that again, since I messed that up to further connect with University of Minnesota Swine extension, please visit the swine specific web pages on University of Minnesota's extension website at www.extension.umnedu backslash swine on those pages you will find connections to our blog and 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