Episode 233 - Milk and meat are safe, H5N1 bulk tank testing data, H5N1 seroconversion in impacted populations - UMN Extension's The Moos Room
What is up, everybody? This is doctor Joe Armstrong. It is 11 AM on 5/21/24. It's been a little bit since we talked, but had a lot going on trying to get some research going, trying to figure out the best questions to ask and the best way to spend some funds to get those questions answered. And that's what I've been working on for the most part, besides trying to keep up with all the new information that's coming out about our situation.
Dr. Joe Armstrong:So let's jump in, get an update on where we're at, and then we'll get into some new data that's out. So as of today, we have Texas, New Mexico, Colorado, Kansas, South Dakota, Idaho, Michigan, Ohio, and North Carolina on the official list. There continues to be new detections in new herds around the country. There also continues to be many poultry flocks impacted by HPAI, including flocks in Minnesota. We had several HPAI detections in flocks in Minnesota over the weekend.
Dr. Joe Armstrong:And with much of that sequencing going public and being made available, we are going to know if this strain has been in cows before it made its way to these poultry flocks. That's gonna be really important because are there ways for this virus to move around, and can it be transferred by wild birds from area to area? Absolutely. Can it be transferred by cats? Probably.
Dr. Joe Armstrong:But what we're looking at is the amount of virus in the environment. And when we have a dairy that is impacted and affected by the virus, there's likely a large amount of virus in the area. So can we for sure say that dairies that are impacted are posing a bigger risk to poultry flocks in the area? We can't say a 100%, but the evidence is really stacking up to say and show that if we have a impacted dairy with the virus, it may pose a risk to those around it because of the local area spread, whether that's through wild birds or cats or some other means that we do not know yet. The evidence is pointing to the fact that a dairy that is impacted with the virus increases the risk to other operations in that area, both other dairies and poultry operations as well.
Dr. Joe Armstrong:So the biggest concern for me when we talk about this situation is that we are set up for the industries to butt heads, and we can't afford that. We've talked about that on the show already about ag fighting ag, and we can't have that. We need agriculture to all be on the same side in this. But that is predicated on us doing something to control, whether that is just notifying those around us if we are impacted so that other operations can take extra steps to make sure they're protected a little bit more than they already are, or true control measures where we're looking at what can we do in terms of biocontainment to truly keep this virus on the premise once we've identified it's there. That is biocontainment.
Dr. Joe Armstrong:We need to biocontain, keep the virus on the premise as much as possible once we've identified that it's there. Alright. Enough of soapboxing issues. Let's get to the facts. On May 10th, FDA came out with more information basically confirming what we already knew.
Dr. Joe Armstrong:Milk is safe. They had preliminary results already telling us that those PCR positive samples were taken to the next step and were showing that there was no live infectious virus and that pasteurization works. And on May 10th, FDA came out with more data to say the same thing. Pasteurization works. Milk is safe.
Dr. Joe Armstrong:No live or infectious virus detected at all in any on the shelf milk samples that were taken, including samples from 1%, 2%, skim milk, whole milk, yogurt, sour cream, and sour cream like products, all of those things. Everything is safe. Along those same lines, we had some ongoing research from USDA about ground beef. Now initially, they collected ground beef from the shelf from several different locations, and they found no virus. Zero virus.
Dr. Joe Armstrong:But as a follow-up, they wanted to do a ground beef cooking study. In this ground beef cooking study, they made burgers. They made beef patties with ground beef and then they added h five n one virus to the patties. And then they cooked them at different either a 120, 145, or 160 degrees Fahrenheit. There was no virus present in the burgers cooked to a 145 or a 160 degrees.
Dr. Joe Armstrong:Those are recommended cooking temperatures from FSIS. In addition to that, even cooking burgers to a 100 and 20 degrees, which is well below the recommended temperature from FSIS, inactivated the virus. So even cooking to a 120 degrees, we have no live virus anymore. Meaning that cooking meat, even if the virus was present, even low to a 120 degrees Fahrenheit, it would still be safe. I'm not saying to cook your burgers to a 120 degrees, but cooking meat, even if the virus was there, which it is not, has not been found in meat, it would still be safe.
Dr. Joe Armstrong:So, again, more information to tell us what we already knew. Meat is safe. Okay. I promised you new information. This is just purely informational things that I've learned from some of my colleagues who had the opportunity to take samples and look at things before the federal order came down.
Dr. Joe Armstrong:So these are all results from before things were reportable when research was pretty much unimpeded. So keep that in mind. We have samples from before the federal order, and we have that data. The likelihood of us getting more at this point is very low unless there's some exception for research or the reporting requirements at the federal level change in some way. Okay.
Dr. Joe Armstrong:This is from a AABP webinar where we had the opportunity to hear from Drew Megstead, who is a veterinarian who works at the Iowa State University Veterinary Diagnostic Lab. Drew had the opportunity to work with a herd that milks about 26 100 cows, and they were impacted by the virus in mid March. We don't have time to go through everything, but I will hit the highlights and the things that surprised me the most and things that I think are relevant as we move forward looking at what are we gonna do with this in the future. So similar with what we've talked about on this podcast before, we have some clinical case definition things that just add to what are we looking for, what do we see, all of those kind of things. So important when we're talking about this specific set of data.
Dr. Joe Armstrong:They chose to make day 0 the 1st day that the dairy noticed major clinical changes, and they had big increases in the number of clinically affected animals. And the 1st day, they really saw, hey. Something's not right. We're pulling way too many cattle to the hospital pen. That is day 0 when we're talking about this data set.
Dr. Joe Armstrong:So like we've talked about in the past, we have some dry matter decrease with the lowest point of our dry matter intakes being 7 at day 7. So 7 days after we saw the big increase in clinical cases. Over that same stretch of time, we saw our somatic cell go from about 80,000 to a 160,000. So doubled our somatic cell during that peak of our clinical issues. About 16% of the total milking population was clinical at some point and polled.
Dr. Joe Armstrong:So that's all. Just a little bit of background confirms what we kinda saw with the herd dynamics of this and how it works on a herd level and what that case description looks like. The biggest and most valuable piece of this dataset was done with bulk tank testing. This farm had banked frozen samples from every load that went out during a stretch that we wanted to look at, which was right around when they were impacted by H5N1. So Drew and his team at Iowa State took samples and tested them with PCR and with some other methods to look at how did things act over time.
Dr. Joe Armstrong:They had samples from day negative 29 all the way through day 32. So when we talk about that, remember, day 0 is the day that they saw the major increase in clinical cases and pulls to the hospital pen. So we have samples all the way out to 29 days before that and 32 days after that. Now with the dataset, they did some other things. Right?
Dr. Joe Armstrong:They had multiple tankers coming out of this one farm, so they averaged some of the data for the tests that were from 2 days before each data point and 2 days after. So we have a 5 day rolling average for each data point represented in the set. Here is where things get interesting, because day 0, remember, 1st day that we have a noticeable change in how many animals are clinical, how many animals are pulled and going to the hospital pen. Our first PCR positive on bulk tank samples is 16 days before that, on day negative 16. So 16 days before we have a noticeable clinical issue in this herd, we have a positive PCR on the bulk tank.
Dr. Joe Armstrong:When we look at the data, there is a change somewhere around day negative 8 where we have a very sharp spike in how positive the bulk tank is. And that continues to rise. The positivity continues to rise on PCR all the way out till day 5. So 5 days after we have that big jump in clinical animals. From day 5, where we hit our most positive sample on bulk tanks, we have then a gradual decrease, or actually quite a sharp decrease to day 20.
Dr. Joe Armstrong:And then after day 20, we have all samples negative out to day 32, which is the end of this data set. So this is a really, really cool study, and I'm really, really glad that Drew was happy to share this information with everyone and make it so available. The other cool part of what Drew did is he was taking those bulk tank samples and not only testing them with PCR, but he was looking at using an NP ELISA test to look for antibodies in the milk to decide if we can use that to show whether or not this herd has been exposed or are they recovering or where does that fall in line with the PCR testing at the bulk tank. Very, very, very good idea. Very, very unlikely to have more of this kind of data as well due to serology being reportable.
Dr. Joe Armstrong:And as long as that stays that way, again, we are not going to see more data like this, most likely. The value in a data set like this is being able to sample serially, so over and over again to see the clinical picture over time. As the federal order sits right now, if I had an impacted herd, and I wanted to look at what's going on over time, every time I get a positive result on either PCR or serology, my 30 days of not being able to move animals interstate lactating animals would extend another 30 days. So I'm drawing out this stoppage of movement every time I test, but the most valuable testing is to do it serially, because then we get the most information and we can see how it changes over time. That's not possible when we don't have exceptions for research or we're insisting that this is how it's going to work once we know a herd is impacted.
Dr. Joe Armstrong:The only way to learn more about this is to get more data, and the only way to have evidence based policy go into place that has science behind it is to get more data. And currently, the rules and the way they're written as far as the federal order do not allow for that. All right. We slid into a little soapboxing there, and we'll go back to Doctor. Megsat's data.
Dr. Joe Armstrong:So what did he see when he looked for antibodies in the milk? Well, not super surprising, because this is flu. We have a immediate and pretty robust response with antibodies. So remember, day 0 is the 1st day they had a noticeable change in the number of clinical animals on their farm, and we saw big numbers spike for polls. The big change in antibodies is between day 5 day 7.
Dr. Joe Armstrong:Before day 5, all of our antibody testing was negative. After day 7, all of our antibody testing is positive in the bulk tank milk. That is a fast response. Now if we overlap that with our PCR data, the presence of antibodies in the milk detectable between day 5 and day 7 is also a time when we're still seeing PCR positives on the bulk tank. Is that surprising?
Dr. Joe Armstrong:No. Remember that PCR does not give you information about the viability of virus. Most PCR tests don't. This one that doctor Megsat used does not give you information about viability of that virus. The most powerful thing that we have for testing, in my opinion, is to combine the 2, looking at PCR and serology.
Dr. Joe Armstrong:So if we see serology positive, we know that animal's been exposed and they have mounted a response, which is really important because when we talk about flu and specific strains, once you have seen it and you've seroconverted, you've mounted a response and you have antibodies, you're no longer naive, you are resistant. The likelihood of you getting that same virus, that same strain again, is very low. So it's very important to know if animals and herds have seen the virus already or not. Now we'll get into a little more discussion about populations and what it looks like for seroconversion at a population level because we have a little data on that as well. But for now, it's really cool to look at the bulk tank and say, has this herd seen this disease or not?
Dr. Joe Armstrong:Because if we have antibodies in the bulk tank, and we know this herd has seen the disease already, and we combine that with a negative PCR result, that is now a risk assessment tool. With positive serology and negative PCR, that herd would be in a lower risk category than a herd that is completely naive because we know they've already seen it, and they're not currently infected. It was really, really cool information, great study, and I really appreciate doctor Megstead being willing to share everything so openly. All right. Let's move on to a brief other study that I think is really good to talk about, and that is a study from Doctor.
Dr. Joe Armstrong:Scanlan Daniels, who is a swine vet, but who has been working because of his experience in outbreaks and diseases that need to get under control on the swine side. He's been working with a couple of dairies, and he had some data to share with us. Now the sample size isn't huge. It's 56 samples, but the key to these samples is when they were taken. So in this dairy, this was an impacted dairy, and we are looking at serum samples and serology data from animals 43 days after they were impacted by the virus.
Dr. Joe Armstrong:So we've been hearing a lot about mid and long days in milk cows or mid to late lactation cows and how they might be more impacted than other populations. When we pull that group out in this dataset to look at who seroconverted and who didn't, we found, I think, some concerning data. In that mid to late lactation group, 43 days after seeing the virus at the herd level, there are 20% of those animals that did not seroconvert. So 80% of them did, and they have an antibody response. They are sero positive, but 20% of that group is sero negative.
Dr. Joe Armstrong:When we look at seropositive versus seronegative, what we're concerned about is that a seronegative animal or a seronegative group is still naive to the virus. They are still at risk and potentially could be infected and impacted by the virus. Whereas a seropositive group, like we talked about earlier, is resistant, and they likely will not succumb to that same virus. We see some similar trends when we look at first lactation cows as well. So these would have been the animals that were present during the outbreak and either freshened before the outbreak or after.
Dr. Joe Armstrong:Did they seroconvert or not? And we see an even bigger proportion of this group did not seroconvert. So depending on the cutoff that we use, whether it's a 0.5 or 0.6, we can see that anywhere from 70 to 50% of these animals did not seroconvert. So anywhere from 33% to 50% of these animals did seroconvert. That's a huge proportion that did not seroconvert and did not apparently become infected with the virus.
Dr. Joe Armstrong:So on the surface, that might seem like a good thing because it's just not infecting that many animals. But when we look at the way influenza works, it is concerning because, ideally, we would have complete uniform exposure. Everyone sees it. Everyone seroconverts. Everyone becomes resistant.
Dr. Joe Armstrong:When we don't have uniform exposure and we have large proportions of the population that are still naive, it opens the door for influenza to circulate again in that naive population. What we worry about is the more that influenza circulates, the more it has the opportunity to change. As it changes and if it circulates enough in a naive population, it might change enough that it can go back to that group that already saw the previous version and reinfect that group. Now we have a problem with it becoming endemic in a given population. That is the whole reasoning behind not introducing new animals to a herd when you are impacted.
Dr. Joe Armstrong:Because the more you bring in naive animals that have never seen the virus to a population that is currently infected, the more opportunities you give that virus to see new animals and circulate further. So, we have some big challenges ahead of us. Are we up to the challenge as a dairy industry, as a cattle industry as a whole? Absolutely. Do we need to reinvent the wheel?
Dr. Joe Armstrong:No. We have some amazing colleagues on the poultry and the swine side that can help us and have laid the groundwork. We can ask them for advice, and they are more than happy to share it because they've been through it before. Where do we go from here? It's a tricky road forward because of the federal order and the way it's set up.
Dr. Joe Armstrong:Without an exception for research, we're gonna have a hard time learning as much as we need to. But I think there's some other avenues to chase and things to look at that we we really need to know. And one of those things is what is this doing in the environment? Where is it going? How is it moving within a local area?
Dr. Joe Armstrong:Where is it on an impacted farm? What about manure? What about urine? What about cats? There's all sorts of ways that this virus could potentially move, and we need to find those.
Dr. Joe Armstrong:Just as important as identifying where it can move is identifying where it can't. Looking for those things is really important, and I think that's one of the steps that I'm gonna try to take next. Now we have to be very careful saying anything about what influenza cannot do, because it changes like we talked about. And as soon as you think you know the rules, they change again. The more information, the better.
Dr. Joe Armstrong:That is the way forward. With that, I'm done talking at you for today. If you have scathing rebuttals, questions, or comments, those go to themoosroom@umn.edu. You can call me at 612-624-3610. Check us out on the web at extension.umn.edu.
Dr. Joe Armstrong:That's where I'll end the plugs today. Thank you everybody for listening. I will talk to you soon.
