Veterinary Vertex
Veterinary Vertex is a weekly podcast that takes you behind the scenes of the clinical and research discoveries published in the Journal of the American Veterinary Medical Association (JAVMA) and the American Journal of Veterinary Research (AJVR). Tune in to learn about cutting-edge veterinary research and gain in-depth insights you won’t find anywhere else. Come away with knowledge you can put to use in your own practice – along with a healthy dose of inspiration to remind you what you love about veterinary medicine.
Veterinary Vertex
When Wildlife Meets Urban Life: The Salmonella Connection
Salmonellosis is far more than just a risk from undercooked burgers. In this eye-opening conversation, wildlife health experts Dr. Sonia Hernandez and Dr. Kim Perez reveal how everyday environmental exposures may pose significant yet underrecognized transmission hazards for this dangerous bacteria.
The researchers unpack their fascinating studies of white ibises adapting to urban environments in Florida and the persistence of Salmonella on shared surfaces like picnic tables and bird feeders. Their findings challenge conventional wisdom about disease transmission, showing how dried bird droppings can harbor infectious bacteria long after they appear harmless. "A lot of times we see these fecal stains and we think, well, they're not wet, they're not fresh, but they don't necessarily have to be in order to still have infectious Salmonella in them," Dr. Hernandez explains.
The conversation explores surprising discoveries about immunity patterns in young birds and the concerning ineffectiveness of antimicrobial coatings on bird feeders. The researchers discuss how their work sits at the intersection of wildlife conservation, public health, and veterinary medicine—exemplifying the One Health approach. They raise important questions about wildlife feeding practices, noting that while bird feeders bring joy to many, they may create disease hotspots affecting not just birds but also squirrels, raccoons, household pets, and ultimately humans.
For veterinarians and the public alike, this episode offers practical insights into reducing Salmonella risks without sacrificing our connections to wildlife and pets. The key takeaway? Simple habits like handwashing after outdoor activities or pet handling remain our best defense against this widespread pathogen. As Dr. Hernandez notes, "I think when I was little, I was always taught wash your hands before you eat. I think we should bring that back."
JAVMA article: https://doi.org/10.2460/javma.25.03.0144
AJVR article: https://doi.org/10.2460/ajvr.24.12.0397
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Speaker 2:You're listening to Veterinary Vertex, a podcast of the AVMA Journals. In this episode, we chat about salmonellosis with our guests Sonia Hernandez and Kim Perez.
Speaker 3:Welcome listeners. I'm Editor-in-Chief Lisa Fortier, and I'm joined by Associate Editor Sarah Wright. Today, on this episode, we have Sonia and repeat guest Kim joining us. Sonia and Kim I was fascinated by these two articles and, as a kid who picnicked all the time, I can't believe I didn't get sick. So really appreciate you contributing these articles and for taking the time to be with us here today. Thanks very much, it's a pleasure. Thank you for having us.
Speaker 2:All right, let's dive right in. So, sonia, your Javmon AJBR Current Sin 1 Health articles discuss how salmonellosis is a significant public health threat. Please share with our listeners the background on these articles.
Speaker 5:I think the foundation for both of these articles is the fact that for a long time we've known that salmonellosis in people is a food safety issue, and I think that public health agencies and the CDC have done a great job of addressing that aspect of it with education, and veterinarians have also been a real big part of disseminating education on how to keep people healthy with regards to preparing eggs and meat, etc. But we've also known, and have grown to really understand, that salmonellosis can also be acquired through animal contact, and less perhaps well-known is through environmental contact, and that's the piece that we wanted to contribute to with various different studies is that growing number of human salmonellosis cases that are acquired in ways that are not so clear to public health agencies. By the way, these articles are also about the fact that salmonella is a one health issue and thus salmonella also impacts animals significantly, and of course, we care about animals.
Speaker 2:I feel like the case that always comes to mind is like the little boy goes to the pet store, picks out a turtle that he wants, gives the turtle a kiss and you're like, no, don't do it.
Speaker 5:I have such a question, a picture in one of my PowerPoints about salmonellosis.
Speaker 2:Oh yeah. So, Kim, what are the important take-home messages from these articles?
Speaker 4:Yeah, so I think these two studies really highlight that salmonella, you know, cannot only circulate amongst wild birds, like the white ibis, you know, but they can also persist on shared environmental surfaces. As you know, dr Hernandez alluded to creating opportunities, really nice opportunities for a transmission. So together these findings really reinforce that environmental contamination by wildlife feces. You know, specifically birds in our case, is a real and underestimated exposure route for salmonella. And even without, you know, clinical signs in birds, asymptomatic shedding can still present transmission hazards to pets and humans and other wildlife as well. They'll present transmission hazards to pets and humans and other wildlife as well.
Speaker 3:Yeah, I think it's really quite fascinating to think the picnic table part is what really. I was like whoa, that's crazy. It just says wash your hands, wash your hands, wash your hands.
Speaker 5:Well, and also just kind of look right, because a lot of times we see these fecal stains and we think, well, you know, they're not wet, they're not fresh, but, like we demonstrated, they don't necessarily have to be in order to still have infectious salmonella in them.
Speaker 3:Very good, point, Sonia, while I have you. What sparked your interest in salmonellosis?
Speaker 5:Wow, you know, I think you know I care a lot about animal health, right, and my whole career has been devoted to wildlife health, and salmonella is not one of those diseases that necessarily kills adult birds, except for some very interesting circumstances, and two of them are really like at the intersection of where I work. So we started studying white ibises 16 years ago, basically because we wanted to know how come this really cool but very unusual bird would adapt to urban settings, and we noticed that they left a lot of feces on the sidewalk. We were very concerned that they would adapt to cities, which was great for them because they were losing their natural wetlands, and that people would tolerate them for a time and they do, they feed them and they enjoy them but that they could maybe transition over to becoming pest species because they were leaving so much feces on the sidewalk. So we wanted to get ahead of that and kind of look at it, understand the real risk and then educate people about it, so that we don't end up having to manage these birds in ways that later become a real problem for the birds themselves. Right, Like the way that, for example, Australian ibises are managed.
Speaker 5:They've become a real problem in some places in Australia they go around to garbage cans, they steal food from people. They're noisy, they're dirty and people have started to associate them negatively. So we wanted to kind of get ahead of that issue, at least with the ibis, Now with the bird feeders. That's really, you know, simultaneously both a human health problem but also a bird problem. Tens of thousands of songbirds die every year from salmonellosis across the country and every once in a while we get these huge mortality outbreaks that almost blanket the entire nation. So I had an interest in that. So it's both sort of like an ecological conservation issue but also a wildlife health interest for me.
Speaker 3:Yeah, I think that's a really good point Resource provisioning maybe we can get you to write about that as well. And, in addition, to wash your hands, stop feeding the wildlife.
Speaker 5:Yeah, it's never good for either wildlife or people when we have animals that get habituated to getting fed. I mean, you've heard the old adage like a fed bear is a dead bear. You could probably say the same thing about populations of birds that get accustomed to being fed in cities, for sure.
Speaker 3:Or beaches. Kim, what sparked your interest in salmonellosis?
Speaker 4:Yeah, so I've always had an interest in the interface of wildlife, livestock, public health and the environment, and luckily for me, salmonella kind of sits right at that intersection and it's a pathogen that can circulate in wild animals. However, it can also be transmitted to pets and people and cause serious illness, as Dr Hernandez mentioned. And what specifically drew me into salmonellosis is the fact that it isn't just a foodborne issue, it's a one health issue. So in our work we've seen firsthand how simple actions like putting up a bird feeder or feeding ibis at a park can unintentionally set the stage for disease transmission. So studying salmonella helps us ask bigger questions about urban ecology, wildlife behavior and how human activity really shapes pathogen dynamics.
Speaker 3:There's two key opinion leaders in this area. You outlined some of the important take-home messages, but always, even if you're a key opinion leader in this area, you outlined some of the important take-home messages, but always, even if you're a key opinion leader, when you pull all this information together, there's something that surprises you. So for either one of you to go first Sonia, maybe you what was the most surprising finding from this set of articles? Oh boy.
Speaker 5:I mean, you know, lisa and I, anytime you do science, you think you've got the answers, and then you get surprised by so many different things. I mean, I'll talk about the white ibis study first and then Kim perhaps can chime in on the other one, but I will say first of all, we captured ibises from the Everglades young ibis and we knew that the adults were reservoirs. We knew that the prevalence of adult ibis was about 27%, but we did not expect that when we caught baby ibises and brought them in for an infection trial, that they would already be shedding salmonella at such high prevalences, shedding salmonella at such high prevalences. What was interesting, though, is that even though they were shedding after they matured, after their GI microbiome matured, then they stopped shedding altogether. So then we thought, okay, good, you know, we waited, and we had a long, long period where no bird was positive for salmonella. When we went to go infect them which is how you do infection trials with appropriate numbers of salmonella typhimurium and especially got a pathogenic strain of salmonella typhimurium, we could not infect them.
Speaker 5:Yeah, there weren't that many birds that we could successfully infect, and that kind of surprised me. I mean, if you read about salmonella and immunity to salmonella. The evidence for it is really scant, even in people, yeah. But we know, we suspect, that at the cellular level, like at the intestinal level, there probably is more immunity than one thinks, and so I wonder if that was what happened with our birds. Right, we know we did all the quality control to make sure that the salmonella we had was infectious. We checked before and after, and yet we still did not get that many birds. So it really does give me hope to the fact that if birds are exposed with low levels early on, then maybe that means immunity for them later.
Speaker 3:Yeah, huge opportunity, Kim. How about you? What surprised you in these articles?
Speaker 4:Yeah, so for me, in our American Journal of Veterinary Research, our salmonella persistence trial, I was really surprised that the antimicrobial coating that we utilize on our feeders didn't really significantly reduce salmonella persistence. Dr Hernandez mentioned earlier as well just the fact that salmonella can persist on these various surfaces for such a long time, even if it looks as she said. You know it's a little spot that's on the picnic table and you may think, oh it's. You know it's dried up, it's probably been there for you know, a few days. There's still something, there's the potential that something still could be there. So those were really the two kind of wow factors for me with our studies.
Speaker 2:Definitely very timely, especially with it being summer and people going out for picnics and things. So hopefully people that are listening to this are just hyper aware now of definitely public health concerns when they're out in these environments. So, sonia, what are the next steps to research in salmonellosis?
Speaker 5:Oh, wow, we have so many things. I mean, we are right now preparing another manuscript in which we actually looked at nestlings that are infected by both salmonella and vibrio. There are some different dynamics going on between vibrio and salmonella and Vibrio. There are some different dynamics going on between Vibrio and Salmonella, especially for coastal white ibises in Florida. But Kim's work is probably also really relevant.
Speaker 5:So she's currently working on bird feeder Salmonellosis and looking at both the prevalence and also, like, all of the dynamics that go on at the bird feeder. And, surprise, surprise, we're probably not going to find an avian reservoir, but rather we're going to find that the bird feeder itself is the issue. And you know wildlife health people, we've always thought that was the case, that bird feeders are a focus of transmission and of persistence, and, of course, we struggle with the concept of whether to recommend bird feeding or not. As far as salmonella is concerned, it's probably an issue. So we'll continue to look at these things for years to come. There's so many other questions we haven't answered. I mean, why type of merium and why some birds die and others don't? I mean, those are the kinds of things that we would like to know too.
Speaker 3:What about the squirrels that eat more of the bird food than the birds?
Speaker 5:Yeah, Kim, you want to say something about the squirrels.
Speaker 4:Yeah, so we did a I would say, a pilot trial. How many years ago was this, sonia Probably 2022 now where we actually captured squirrels and we found a decent persistence, uh in in some of the squirrel populations. But that, uh, I'll tease it a little bit. That paper is uh on my docket to to come out, so hopefully I can get that written up at some point between field work and and uh lab time and and office time. So, uh, maybe you'll have us back on for for that paper.
Speaker 5:I mean, squirrels, like most rodents, are really good at maintaining salmonella, but I'm not sure that they're the reservoir either, because their serotypes don't match what the birds have. And so then that leaves you the question with what about all the deer that come? What about all the raccoons? I mean, we had done work on raccoons and possums years ago, and their prevalence is always above 50%, and they do sometimes shed type femurium, but not always. They have a huge stereotype diversity, so the answer is probably not any one thing.
Speaker 3:Makes sense.
Speaker 2:My background is aquatic. So as soon as you said vibrio, my ears perked up a little bit.
Speaker 5:I was like oh, not that one, my background is aquatic, so as soon as you said Vibrio, my ears perked up a little bit. I was like oh, not that one no-transcript.
Speaker 2:Yeah, definitely something to keep an eye on, for sure, and for those of you just joining us, we're discussing salmonellosis with our guests Sonia and Kim hey.
Speaker 3:Sonia over to you. How does your training and your previous experience help you to write these articles and really even get across the finish line? What advice do you have for people who are in the field work trying to balance? You talked about earlier. I have another manuscript. How do you balance all that work and really get the work all the way done and shared with the public?
Speaker 5:Wow, that's a lot. I mean, my training was first as a clinical wildlife veterinarian. I think that understanding how an animal goes from being healthy to being sick and then having interventions that you can make them healthy again has been extremely helpful for me. But I am a researcher now and I have a PhD in ecology and I think putting together both the piece and the foundation from veterinary school and understanding the foundations of pathology and, you know, disease on top of the ecological details is really what gave me the edge or the advantage in understanding systems out in nature, right? So that's the piece about training. I'm sorry. What was the second part? Oh, how do I get it all done? Oh, I don't know. Ai.
Speaker 5:No just kidding. How do I get it all done? I have to say that my graduate students are extremely dedicated. Kim is probably one of those gold star students who really understands how to prioritize the time, how to respond to things in the way that should be done, how to get the work done regardless of the field conditions and lab conditions. I mean, she just recently had a major lab disaster with, you know, a leaky roof, and she was able to get over that, and field conditions are extremely challenging and unpredictable. So I think you have to build in the time and the space with the type of work that we do for plan B, c and D all the time. I love it.
Speaker 4:Kim, how about you?
Speaker 4:Yeah, so my previous work with one of my mentors really helped me understand the significance and interactions between animals and at the time it was primarily dairy cattle humans and the environment and what impacts each one have on one another and disease dynamics.
Speaker 4:And now I'm a PhD student under Dr Sonia Hernandez and Dr Aaron Lipp and you know my graduate work has really provided me with the knowledge and perspective and the passion for wildlife health because, again, I was in the livestock community and environmental systems with Dr Aaron Lipp. So I would say just working with the College of Public Health and Warnell School of Forestry and Natural Resources really highlighted this significance. You know both the good and the bad that organisms can have on these various systems. And then I guess that is kind of like my long-winded way of saying that you know working and thinking in all these various systems really opens your eyes and your mind and allows you to formulate these questions and see things from a different perspective. You know which helps write these articles and which helps get field work done and lab work done and helps you pivot and just keep going and always having your eye on the prize and the goal which is to produce. You know good science and you know hopefully make an impact.
Speaker 3:I hear a lot of the trending word perseverance in both of you too.
Speaker 4:Yes, you have to have a lot of it, I think, to get to where you know Dr Hernandez is, and you know, even in grad school, you have to just put that cap on and keep going.
Speaker 5:And perseverance builds resilience, which I would say is another major character or soft skill to have if you're going to work in wildlife. Health, very well said.
Speaker 2:Now next set of questions is going to be very important for our listeners, and the first one is going to deal with the veterinarian's perspective. So, Sonia, what is one piece of information the veterinarian should know about salmonellosis?
Speaker 5:I think salmonellosis, you know, in vet school, is taught to us as a food safety issue and I think that we need to understand as veterinarians that animal contact with a huge variety of animals can lead to people getting salmonella, but also that it can be easily transmitted among animals, in the clinic, in the wild, in the home.
Speaker 5:And I think it's important for us to sort of teach people very basic things. We assume that people understand that maybe you should need a sandwich right after you handle your pet turtle, or that if you're outside cleaning your bird feeder that you should really make sure to wash your hands afterwards. But these are not necessarily assumptions that we should go by. We should really understand that we play a role in educating people and that they appreciate that. And there's little like things Like, for example, your cat goes outside and catches a sick bird, it can come back and lay on your bed. It can become a reservoir of salmonella, it can pass it on to your dog, to the other cats or on to you. So you know lots of lessons, lots of little nuances that are important.
Speaker 3:What I like most about that is don't blame the burger all the time that's right and on the other side of the relationship.
Speaker 2:what's one thing that clients or the general public should know about salmonellosis?
Speaker 5:Well, I think you know, I think I said some of it. I think that we don't want to scare people away from having animal experiences. We just want them to make sure that they understand that they need to wash their hands after they play with turtles, baby birds, and that salmonella collects in certain environments you know, bird feeders, areas that have feces from animals and things like that and always to, just if you're in doubt, wash your hands. I think when I was little, I was always taught wash your hands before you eat. I think we should bring that back.
Speaker 3:Very good. As we wind down a little bit, we we like to ask a little bit more of a fun question. So we'll start with you, kim. What is the oldest or most interesting item on your desk or in your desk drawer? And, if you have it, feel free to show it on the camera.
Speaker 4:So it's definitely the most interesting thing that I have. I don't have it with me because I'm in my other office, but I have somewhat inherited a life-size cutout of Dean Winchester from Supernatural and he kind of is right in the center of my desk. We have little cubicles and he sits right atop of my book ledge and he stares down at me to make sure that I am doing all of my my tasks properly. So he is kind of like the overseer of the office and kind of the mascot of the lip lab in certain ways. So that's I don't know how, but he just migrated over to my desk one day and he stayed there since. So that's do you dress him up for Christmas? He always has lights on him, so he definitely always has something. But that's actually good. I think we'll do maybe a Christmas hat for Christmas, halloween, halloween, a good mask for Halloween. I think that would be great. I actually like that idea. Thank you so much.
Speaker 5:Sonia, how about you? So again, you caught me in my other office. This is kind of a weird week for us at UGA, but anyhow, I have a couple of things in my desk drawer that remind me of what I one of the reasons why I went to vet school, and that's to work with wildlife, and those are darts. I have a lot of darts sitting on my desk and that's because I remember, you know, as a wildlife, having to have my dart gun and my dart box filled with darts for a variety of different things, and I still miss all the time that I used to spend in the field, which now my grad students get to do.
Speaker 2:Yeah, my cat actually. I think heard you talking earlier about the cats. If you're watching the video, you probably saw her come over. I think, she's now our unofficial third co-host, but thank you so much, sonia and Kim. We appreciate you being here today and also for authoring these great Current. Some what Health articles.
Speaker 5:Thanks so much for the opportunity. It was great, great to talk to you guys and thanks again for highlighting One Health which is so important.
Speaker 2:Thank you, guys for having us and thanks again for highlighting One Health which is so important. Thank you, guys for having us and to our listeners. You can read Sonia and Kim's articles in Javma and AJPR. I'm Sarah Wright with Lisa Fortier. Be on the lookout for next week's episode and don't forget to leave us a rating and review on Apple Podcasts or whatever platform you listen to.
