Science Friday - Autistic Researchers Studying Autism, Canned Salmon Insights, Medieval Friars’ Parasites. August 26, 2022, Part 1

Episode Date: August 26, 2022

California Accelerates Its Push For Electric Cars This week, air pollution regulators in California voted to phase out sales of new gasoline-powered vehicles, with a complete ban on gas car sales by 2035. The decision could have a larger impact on the automobile industry, however, as many states choose to follow California’s lead with regard to air quality and emissions decisions. Sophie Bushwick, technology editor at Scientific American, joins guest host Roxanne Khamsi to help unpack the decision. They also discuss some of the other science stories from this week, including a survey-based study showing that Americans really do care about climate change and support mitigation measures, a look at how sugar substitutes can change the microbiome, and an engineer’s advice for how to build the sturdiest sandcastles.   Meet Two Autistic Researchers Changing How Autism Research Is Done For many decades, autistic people have been defined by non-autistic people, including in science. Since the very beginning of research about autistic people, neurotypical scientists and institutions have been at the helm. The field has largely been defined by what neurotypical researchers are curious about learning, instead of prioritizing research that the autistic community asks for. Because of that, and the invisibility of autistic adults in our society, a large chunk of this research has neglected the needs of autistic people. In many cases, it’s caused harm to the very people the research aims to help. Until recently, there have been very few openly autistic researchers who study autism. But there is a growing body of openly autistic scientists who are using both their expertise and their own lived experiences to help shape the future of autism research. Guest host Roxanne Khamsi speaks with Dr. TC Waisman, a leadership coach and researcher studying autism and higher education, based in Vancouver, British Columbia, and Patrick Dwyer, a Ph.D. candidate studying sensory processing and attention in autism at the University of California, Davis. They talk about the history of autism research, why the inclusion of autistic people in research leads to more helpful outcomes, and how they see the future of autism research changing. Ira Kraemer consulted on this story.   Ecological Data From Deep In The Pantry Most people wouldn’t be excited by a call offering a basement full of canned salmon dating back to the 1970s. But for researchers trying to establish baselines for what’s normal and what’s not when it comes to aquatic parasite populations, the archive of fishy tins, maintained by the Seattle-area Seafood Products Association, was a valuable resource. Natalie Mastick and colleagues combed through the tins with tweezers, counting the numbers of parasitic anisakid worms they found. (Since the salmon was cooked, the worms—though gross—posed no risk to human eaters.) The team found that in their samples of chum and pink salmon, the incidence of parasitic infection increased over the 40 years covered by the salmon archive. The finding might be good news—an increase in the numbers of marine mammals in the area, key hosts for the parasites, could be responsible for the wormy increase. Natalie Mastick, a PhD candidate in the University of Washington’s School of Aquatic and Fishery Sciences, joins guest host Roxanne Khamsi to explain the study.   Medieval Friars’ Farming May Have Caused Tummy Troubles What was life like back in medieval England? You might think that the learned friars who lived in the town of Cambridge—scholars, with access to innovations like latrines and places to wash their hands—might have lived healthier lives than the common folk. But a recent study published in the International Journal of Paleopathology says that, at least when it comes to intestinal parasites, the friars may have been worse off. Dr. Piers Mitchell runs the Cambridge Ancient Parasites Laboratory and is a senior research associate in the McDonald Institute for Archaeological Research. Mitchell and colleagues excavated soil samples from around the pelvises of medieval skeletons in one Cambridge cemetery, then examined the soil microscopically looking for parasite eggs. They found that friars in the cemetery had almost twice the incidence of intestinal parasites as commoners in the town—a fact they speculate could be related to friars using human feces, from the friary latrine, to fertilize the gardens. Mitchell joins guest host Roxanne Khamsi to explain the study.   Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Roxanne Camsey in for Ira Flato. Later this hour, we'll talk to two autistic researchers adding their own lived experience and expertise to the study of autism. And we'll dig into our history with parasites. This week, air pollution regulators in California made a bold move to phase out sales of new gasoline-powered vehicles, with a complete ban on gas car sales by 2035. Joining me now to talk about this and other science stories of the week is Sophie Bushwick, technology editor at Scientific American based in New York City. Sophie, welcome back to Science Friday. Thanks for being here.

Thank you. I'm excited to be here. So let's talk first about this car decision. What exactly are these regulators in California banning? So California regulators have done. said that by 2035, no gas powered cars can be sold. So electric or hydrogen powered vehicles will be all of the new vehicles sold. Used vehicles can still be there. And the other interesting thing is that they're phasing them out. So by 2026, already 35% of new passenger vehicles have to produce zero emissions. Wow. So it's not so much about going cold turkey. Exactly. They're easing into it. But it is still a

significant change. And if other states follow them, this could affect a third of all automobile sales in the U.S. And so to make this change, is there going to be a need for a new infrastructure, new charging stations? What's needed to make this happen? Absolutely. So one of the things that electric vehicles require are charging stations so they can go distances. And California is also making moves to put money towards establishing those. Another issue is that if you have a lot of electric cars charging off the grid, you'll need to make sure that there's enough electricity for them. So that will also have to be addressed by 2035. Hmm.

California is super trendy. It's on trend. What is the likelihood that other states will make the similar kind of move? There's about 16 states that tend to follow California's lead when it comes to regulating auto emissions. And so those are pretty likely to follow suit. This could be a absolutely enormous impact on emissions. Transportation is the main source.

of greenhouse gas emissions in the United States. So not just cars, but the aviation industry as well. Still, cars are a big chunk of that. And if all these states do follow California's lead here, this could be just as significant as the passage of the Inflation Reduction Act in terms of the future of greenhouse gas emissions and climate change in the U.S. Whoa. And since we're talking about climate here, you have a related story this week about Americans' opinions about climate change mitigation. There's an unexpected. to twist here in what researchers found? Yes, this is fascinating. So measures like California's rule and like the IRA are actually pretty popular. A big majority of Americans think that climate change

is a bad thing and support measures to mitigate climate change and to try to prevent some of the worst harms from it. And yet, even though we think these things ourselves, we underestimate made hugely what our neighbors think of this. Something like 80 to 90 percent of people surveyed in this new survey underestimated how much public support there is for climate change mitigation measures. And this is a really big deal because if you think that you're the only one who is worried about climate change, you're less likely to speak up and perhaps less likely to, if you are a member of Congress, you might be less likely to put forward measures to to try to reduce the impact of climate change, when in reality, these measures are popular and

people think that they're necessary. I mean, this is a really fascinating insight into how we think others think about climate change. Do you think that this kind of false social reality shapes action on other issues as well? Yes, I think that our willingness to, for example, act on climate change, but also to act on a bunch of other measures, that's tempered by what we think other people will think. We don't want to necessarily support a policy if we think it's super unpopular with everyone else, even if we ourselves believe in it. So I think having an accurate idea of what our neighbors think could be pretty important. And it probably is up to the researchers who do these surveys and to the journalists who cover them to make sure people are aware of what their neighbors think and not just what they think their neighbors think.

Yeah, this is definitely making me rethink how I think about what others think. So moving to a different topic, many people turn to sugar substitutes in a desire to cut calories or because they're concerned about their blood sugar. Yet there's new research saying that those substitutes might actually affect blood sugar. How does that all work? So we tend to think of sugar substitutes as having zero calories and then just sort of moving through the body and not affecting us. But previous studies in rodents have found that these sugar substitutes do seem to affect blood sugar on the, the gut microbiome. And a new study in humans found that that is the case. So they got a cohort of people who don't typically eat calorie-free sweeteners. And then they gave them four sugar substitutes

or a filler, which is the non-active ingredient in, you know, the little packet of sugar substitute you might grab at a coffee shop. And in this study, two of the sugar substitutes, saccharin and sucralose, were linked to spikes in glucose levels, and all four of them were linked to changes in the gut microbiome. So what they did is they had people either eat a specific sugar substitute or not for two weeks, and then they had them take actual glucose and measured how their blood responded to it. And people who had been taking saccharin or sucralose, their blood sugar levels spiked more in reaction to glucose than those who hadn't been. And for all of them, when the researchers measured their gut microbiomes before and after, they did see changes. Well, definitely, it's finding that sweet spot, you could say.

But this next one we're going to talk about is a little creepy. People that look like you might actually share chunks of your DNA with you, even if you're not related at all. And that's the thing that surprised me the most. I think this is fascinating. So it started with an artist, actually, a photographer of Francois Brunel doing a photography project where he took pairs of people who were unrelated but looked alike and photographed them together. And what researchers have now done is they looked at 32 pairs from this photography project and they tested their DNA.

And what they found is in half of the pairs, there were genetic similarities in the DNA of these two people. who thought they were completely unrelated. And are there any practical applications here with this new binding? Well, it could be interesting to see how this affects, for instance, likelihood of developing a disease. So if you and your doppelganger have similar DNA, maybe you're both susceptible to cancer. So this could be used for that. But just as interesting as the fact that some of these doppelgangers had similar DNA was the fact that some of these doppelgangers didn't. So for about half the pairs, there weren't significant similarities in DNA, even though they looked so much alike.

And it suggests that there's only so many different combinations of features that you can put on a face before you start turning out faces that look different. So I think that's fascinating that someone who you're not that genetically close to could still look just like you. Yeah. Yeah. And it makes me want to find my doppelganger and maybe do some genetic analysis to see if we're related. Absolutely. I'm going to be staring at all the dark-haired women. I see, oh, are you, are you look, do you look like me? So now that we're approaching the end of summer, you also have a story about theories on how we can better engineer sandcastles. Can you say something about that? So this is a very important engineering project for anyone

who's planning to head to the beach before the end of summer. Yes. And the key to engineering the perfect sandcastle has to do with a couple things. One of them is the ratio of water. to sand. So in laboratory conditions, you would want to have one parts water to eight parts dry sand. But you don't necessarily, you're not in the lab when you're out on the shore. You know, you're dealing with yelling kids and birds and trying to find the spot in between everyone else's beach umbrellas. So geotechnical engineers would recommend maybe you want to go down to where, about where the tide line is at low tide and you want to take sand from that area. That's going to be your sort of sweet spot of sand to water.

And then the other really important thing is you've got to pack that sand as tight as possible. So you can do the classic traditional method of smushing sand down into a pale or into a mold and then flipping it upside down and using that to make blocks. But what this engineer actually recommends is creating a mound of compacted sand and then carving out your castle from it the way a sculptor carves a statue. from a block of marble. And if you're really serious about this, you might want to actually go beyond the beach. Apparently, having sand grains that are a little rougher and spikier and less regular actually lets them stick together better and gives you a better castle.

So professional sandcastle builders will actually import sand from rivers. So it's closer to the mountains. And apparently those grains are a little spikier and they stick together better and they let you make a more cohesive castle. Wow, it sounds like these castle engineers will build something that's going to last longer than the hour or two when I make them. Oh, yeah, my soon castles collapse almost immediately. I think that I would love to learn from this longevity. Finally, we might like to see familiar faces, but it turns out dogs do too. Can you tell us more about this new study? This is delightful. A researcher noticed that his dog's eyes seemed to be filled with tears when she interacted with her puppies. And then he also noticed that the dog seemed to be tearing up when she saw him.

So what he did was he studied a couple different things. First of all was do dogs eyes full with tears and what makes that happen? And he found that oxytocin, which is associated with social bonding, levels of oxytocin can cause a dog's eyes to well up. And the other thing is that, yes, when a dog's owner comes in the door, its eyes do fill with tears in a way that it wouldn't respond to, say, going to, to a doggy daycare. You know, it might be act excited, but its eyes don't water in the same way. So this suggests that dogs are reacting socially to the presence of this familiar human, and their reaction then intensifies our reaction to them. When humans looked at pictures of dogs where either their eyes were filled with tears or they weren't, we were more likely to want to cuddle and play

with the teary-eyed ones. So you could see this creating a feedback loop that helps dogs and owner's bond. And they're happy tears, just to be clear. I mean, I hope so. Yes, they seem to be mediated by this bonding hormone. We'll tell ourselves that. Well, thanks so much, Sophie. Thanks for having me. Sophie Bushwick is Technology Editor for Scientific American. When we come back, studies on autistic people have oftentimes been hurtful and harmful to the very communities they seek to help. But there is a growing number of autistic researchers who study autism. or trying to reshape the future of the field. We'll talk to two of them right after the break.

This is Science Friday. I'm Roxanne Kamsi. Since the very beginning of research about autistic people, neuropypical scientists have been at the helm. Because of that, plus the invisibility of autistic adults in our society, a big chunk of the research has neglected the needs of autistic people. Sometimes it's gone beyond that and even been hurtful. and harmful to the very people it aims to help. Until just recently, there have been very few

openly autistic researchers who are studying autism. But there's a growing group of autistic researchers who are bringing both their expertise and their own lived experiences to help shape the future of autism research. Here to tell us more are my guests. Dr. T.C. Weisman, a leadership coach and researcher studying autism and higher education based in Vancouver, British Columbia, and Patrick Dwyer, who is a PhD candidate studying sensory processing and attention in autism at the University of California, Davis. Welcome both of you to Science Friday. Thank you. Thank you so much for inviting us, yes.

So Patrick, what have neurotypical researchers historically focused on when it comes to autism research? Some people have been doing more basic biomedical type research, looking at the genetics of autism, looking at animal models, models doing various kinds of neuroscience work, it's been neglecting a lot of the most important barriers that we actually face. A lot of the challenges that are faced by autistic people, including those with high support needs, actually have to do with societal discrimination, with a lack of availability of supports, with a lack of inclusiveness, with stigma, all of these things. They're very important to all autistic people, regardless of ability, and that was being completely missed. Meanwhile, some of the efforts to promote secure were actually and still are harmful by, you know,

telling people that there's something wrong with them, by trying to force compliance. So yes, I would say that definitely our fields has a legacy of harm that is unfortunately very serious. T.C., what do you see as the biggest problems in autism research right now? Yeah, I totally agree. with what Patrick's saying. And to build on that, you know, our research typically and historically hasn't necessarily focused on creating better outcomes for autistic individuals in terms of our health, our education, our livelihood, our well-being. So unfortunately, that's translated to an emphasis on deficit perspectives and autism and looking at our lack of abilities rather than strengths, talents, et cetera. And it's also privileged non-autistic perspectives, research

focused on mainly white male representations of autism. So those generalizing, still exists either in plain or subtle ways today regarding what autism looks like in a person and how it's accepted societally. Also, you know, people like me were missing in research, people from different cultural backgrounds, people from different ages, and that kind of thing as well. So a few years ago, the two of you co-founded the Autistic Researchers Committee, which is under the International Society for Autism Research, known also as Inzar. What inspired you to do that? T.C., do you want to start? For me, I just didn't see myself. I didn't hear my voice in autism research. And because I was late diagnosed at 48 years old, it was really frustrating for me that the research sort of seemed kind of siloed in a lot of ways. And so for me, this was an act of resistance and an act of activism, bringing autistic voices to decision-making processes within Insar. And Insar was ready for it. And Insar was an agreement that this was needed.

One of the goals that we had was really to try and promote networking among autistic researchers, help our communities sort of come together a little, as well as to make the INSAR conference itself more accessible for autistic researchers, just because there's just a lot of barriers, a lot of things that unfortunately make quite difficult for autistic people to attend research conferences. And T.C., you mentioned that you were diagnosed with autism at age 48. Can you tell us a little bit more about your research and how you got into it? When I was diagnosed at 48, by the way, it was one month prior to starting my doctoral degree. So I knew very little about autism. And so I changed my research focus and focused really on, you know, how the heck did I get here? How am I autistic and in the education system? And I'm this old and this is happening. And I'm not getting the supports I know. need and, you know, I'd fallen through the cracks. So my research really focused on that,

how higher education leaders, faculty, and staff can enhance services and outcomes for autistic individuals and near-divergent individuals at the post-secondary level. Patrick, do you have a reason that you got inspired to study autism? Yeah, so because I am a privileged white male, at least in part, I got diagnosed earlier than T.C. I was 11. So, but, But it was still late enough that it answered a lot of questions. I knew I was different from other people. I was looking around for an explanation of autism provided that. And it connected me to a community of people.

And over the years after being diagnosed, I was able to see just how many challenges our community is facing, just how marginalized we are, just how much people are struggling with mental health, with employment, with just trying to exist in the world. And so, of course, I wanted to do something to see if, you know, we could break some of these barriers. And your research, I think, also focuses on sensory processing.

Is that right? How would you explain that to somebody who's not familiar with what that means? Well, that, too, you know, comes directly from my own experiences. I was struggling a lot with sensory overloads, especially when I was younger in the school system where there's just so much sensory stimulation. It's hard to describe, though, because it's so variable depending on the specific autistic person and the contacts that they're in

and what's our sensory stimuli they're exposed to. Sometimes it's that people have a real aversion to particular textures, scratchy fabrics, tastes and food can be a huge thing. And if we can't get some of the foods that we can actually tolerate, that can be a big problem. But then there's also the auditory aspects where you can just be distressed and completely overwhelmed if there's too much auditory stimulation, but then there's also particular

sounds that can be really aggravating and annoying, even if they're not overwhelming or quiet sounds, they can be really distracting and make it impossible to focus. And it's all very contextual. It depends on attention, I think. It depends on one's mood and mental state. And it's something that, unfortunately, is very difficult for other people to understand because it's perhaps a bit outside their experience. And because it's hard to understand because it's so very variable from context, context,

you know, often people can doubt that it's real. And I got a lot of that. I was younger people thinking that I was making some of it up for it trying to rationalize, you know, well, this environment is noisier than that environment. But Patrick's fine in that noisy environment, but not this somewhat quieter one, what's going on there. And there's still a lot of things that we don't fully understand about sensory processing and often.

Do you find that there's a disconnect between what neurotypical researchers more often focus on versus what autistic communities want out of research? And I don't want to generalize about neurotypical researchers and near divergent researchers' priorities, but I can tell you that coming from a particular community informs me in a different way about the priorities from within that community. So, for example, I'm Black, Indigenous, Pacifica, South Asian, and I'm autistic. And so my lived experiences, you know, I don't get to put those down.

I don't get to forget about it. The world treats me in a certain way every moment, every time I walk out the door. So when you come from inside that experience, there are subtle pieces of knowledge, there are questions, dreams, concerns that are relevant to us that wouldn't even land on the radar of someone who comes from my side of the experience. For example, for me, the barriers that existed to getting a diagnosis, you know, the cultural nuances that make it difficult to see us as autistic, the biases. You know, I was looked at as having behavioral issues rather than being autistic. And we're talking about a community, an autistic community

that is as deep as all the cultures in the world, as wide as the spectrum range of expressions of autism, as vast as the kinds of intersections, you know, that include age, co-occurring disabilities. So our research priorities from within the communities are already plentiful. And, you know, here we are in all our intersectional glory to represent ourselves fully in autism research. Absolutely. Yes. Yes. If you look at the distribution of where autism research money is going, you know, it's to things like neuroscience, understanding the causes and ideology of autism and doing surveillance to figure out how many autistic people there are. And really, it's only a very small pittance that is going to these very important priorities that TC is saying. And I'm not saying

that the things that I was named before are valuables, but there's clearly a difference in the priorities. And so I see that we tend to gravitate towards much more applied research that focusing, you know, on society and societal barriers to a much greater extent than research that's focused on like cure type things, obviously. You know, research that's exploring identity and intersectional identity and all of those barriers and challenges and discrimination. There's research looking at the accessibility of different systems. I think it is quite different on average. Your autistic autism researcher would most likely be studying versus an erypical autism researcher.

Tisi, I was actually curious if I could follow up and ask you what you think the reason is that more funding isn't going to research led by autistic people? Well, I think things are changing. And this is the wonderful thing that's happening. You know, things are changing and funding, for example, the autistic research is a review board, which I was a part of and Patrick is a part of, you know, so we're part of that sort of being able to review research that's coming out

and ensuring that there are certain, you know, aspects of the research that are being upheld, that are more respectful to us, such as participatory research. And, you know, it's partly being driven by social aspects of our disability community, pushing for more respect, pushing for more understanding, pushing for our voices to be included, to be heard, to be a part of the true collaboration throughout the research process,

from research question, all the way to findings, in a real true participatory manner. Like TC, I'm optimistic about the direction we're heading in. I just wanted to add, though, that it can be a bit slow to get there, because new things take time and people are frightened of them and people, you know, will do the kind of research that they're trained to do. So there's, it takes time. People's minions are shifting.

The attitudes are shifting, as T.C. says, what we're starting to prioritize is starting to shift. But there's still a lot of more work that needs to be done in that direction. This is Science Friday from WNYC Studios. I'm talking with two researchers who study autism, Dr. T.C. Weisman and Patrick Dwyer. I'm curious to ask you both what you think autistic researchers bring to the field of autism research that a neurotypical research might not. I think we bring our whole selves.

We bring our Linden intersectional experiences. And that's often missed in research all the way from inquiry to findings, you know, that our tapestry of understanding, we really are, you know, we're removing the one-dimensionality of research. A lot of research is siloed and focused on one aspect of an autistic trait or of autism. And we're much richer than that. You know, we're intersectional with our co-occurring disabilities. We're intersectional with our cultural aspects and, you know, all the nuances in between.

So we are, you know, we bring insight and awareness and knowledge and sometimes even, you know, a desire for practical solutions to problems that most non-autistic researchers are not even aware we need. So, you know, this perspective, I think, is really key. Patrick, there is this idea that people who are autistic shouldn't be included in research on autism because they can't study it objectively. How would you respond to that? I completely disagree with it. Why would neurotypicals be objective and autistic people uniquely bias? Yes, being autistic informs the perspective that we've been.

bring to our work. And it does so in ways that I think TC just very eloquently articulated are often very positive. But being non-autistic and looking from the outside at autism does not make one objective. It just means that one is differently biased and one is biased to value neurotypical norms and perhaps to not understand the sorts of challenges that we experience from the perspective that we have looking, you know, from our own experiences outwards, it's just a different positionality. You know, would you think that if we should say that, you know, gender studies should only be done by men because women would be biased when it comes to gender because that's a more marginalized gender? Of course, it's ridiculous. So we need people, you know, coming from all sorts

at different perspectives, especially those of those who have been marginalized and left out. Yeah, I mean, Patrick said so eloquently as well about, you know, can you imagine this being studied from the outside? For me, as a black person, for example, can you imagine there'd be research on black people without collaboration, without, you know, understanding the culture, you know, without inclusion, without true participatory inclusion in that? You know, when the question comes up about whether we're biased, when we're othering our people, our autistic people, anyway, from the perspective of outside of it, that in itself is a bias. And Patrick clearly defined that. And your research for your PhD focused on how higher education could be more supportive of

autistic students. So what do you see as some of the big barriers to being an autistic person in higher education? Yeah. So in my experience, by far from me personally, the biggest barrier is the lack of education about autism in, you know, in the universities and colleges, you know, everywhere from disability services to faculty, staff, students, and leaders. So for me, that's my personal experience. And we would like to see that there's recognition that near diversity be included in DEI. It's a DEI plus issue, you know, so diversity, equity, and inclusivity. You know, we make sure that our voices are included in the decision making and policies,

and changes that happen, you know, when we're talking about accommodations, that we establish disability cultural centers, you know, for institutional initiatives to promote near diversity and disability, inclusion, and acceptance. So to wrap up and just look to the future of autism research, what does that look like to you? T.C., do you want to start? Yeah, I really hope autism research continues to evolve, that we continue to center intersectional autistic voices in meaningful ways that participatory research becomes, you know, almost old hat because it's, you know, considered sort of the new standard that we,

include cultural lenses in our research that we value the priorities of older autistic people and that research becomes nuanced enough to include autistics who have other co-occurring disabilities that inevitably impact the research findings in ways that are not neat and tidy but are also necessary to know. Yeah, having more community partnership, especially with autistic voices, but really bringing people all dayholders together, including parents and professionals as relevant. and letting people set what the research agenda should be to a much greater extent, I think will address a lot of the issues that we're seeing right now. Well, thank you both so much for joining me today.

Thank you so much for having us. We really appreciate it. Indeed. Dr. T.C. Weisman is a leadership coach and researcher studying autism and higher education based in Vancouver, British Columbia, and Patrick Dwyer is a PhD student studying developmental psychology at the University of California, Davis. We want to say a special thanks to Ira Kramer for consulting on this story. After the break, delving into the world of parasite research. This is Science Friday. I'm Roxanne Kamsie. If you're about to eat lunch, fair warning. You might want to put down that sandwich for this next one. How do you map out a picture of how marine parasite

populations have changed over time. Unfortunately, there's no great archive of historical samples. Or is there? Researchers recently gained access to a trove of canned salmon, reaching back over 40 years, and they're using that information to try to build a baseline for what's normal and what's not in the seas. Joining me now to talk about this is Natalie Mastic, who's a PhD candidate at the University of Washington's School of Aquatic and Fisheries Sciences in Seattle. And she recently presented her work on this at the Ecological Society of America meeting. Welcome Natalie to Science Friday. Thank you for having me. So Natalie, can you talk to me about these salmon samples? Like, tell me a little bit more about where they came from. So the lab that I work in is Dr. Chelsea

Woods Lab at the School of Aquatic and Fisheries Sciences. And we have kind of made a reputation for ourselves as being historical ecologists. So we use any type of historical data we can get our hands on to reconstruct baselines that might have been lost, especially for parasites, which are understudied. And there's an organization local to Seattle called the Seafood Products Association that heard about us in our lab and said, we have a basement full of canned salmon from the 70s and on, are you interested? And after sitting on that invitation for a while, I heard about it and jumped on it because I've been trying to figure out how parasites have changed in salmon for a long time, but there really aren't that many museum specimens available for salmon.

And so all of a sudden there was this trove of salmon. But what does 40 years of salmon in cans look like? I was expecting to see like really old vintage labels. and like ruptured cans and things like that. I didn't see that at all. I saw plastic totes full of unlabeled aluminum cans. It looks a lot like can tuna. It's cooked fish inside of a can. It comes in different sizes.

Some of them are those traditional kind of squatty cans. Some of them are about the sinus of a can of beans. And then there are mega cans that are huge, like Costco size. So you got out. I would assume a can opener, but once you had the cans open, how do you analyze that salmon, flesh, whatever you call it? That was the question, because we're really used to analyzing frozen or fresh or museum specimens of fish, but we hadn't looked at cooked fish before for worms. So it took kind of some trial and error between me and a postdoc in our lab, Rachel Wallachie,

and eventually found out that the most effective way of finding these worms is by using two pairs of forceps, so basically two pairs of tweezers and picking through all of the meat. So you guys were picking through these specimens with your special tweezers. What do you actually see when you're looking? I assume with a microscope. These worms you can see with your naked eye. So once we picked through, we would find a worm that was about a centimeter long, usually, coiled up. And once you kind of get this search image in your head, you can pick them out

pretty easily. And they form these little pockets in the muscle. So you'll find kind of like a little pocket with this little worm coiled up and you can pull it out and see everything that you need to with your naked eye. What's the kind of name that these worms have? These are anasacid nematodes. So they are parasitic nematodes of the family anisacaday. And they are generalist parasites that infect a whole wide range of fish in the North Pacific and also throughout the world. And they use marine mammals as their definitive host. So these fish get eaten by a seal or a whale, and then those parasites infect that marine mammal and reproduce. And then those eggs are released into the ocean through the marine mammals' feces. So it's a cycle of life, but it seems like

we wouldn't have a risk of getting infected with them if we happen to eat some canned salmon or canned fish. I'm guessing that that's not going to hurt us. So these parasites are cooked and the cooking process completely kills them. So if you eat canned fish that have these types of parasites, you're completely fine. Raw fish, on the other hand, if it hasn't been frozen, those worms are still alive and kicking and they can hurt us. They cause food poisoning like symptoms for about a day or two. Well, I'm glad there's a vegan sushi place near my house. So you did all this searching, but can you say a little bit more about what you found?

Yes. So after dissecting a lot of cans, we found a significant increase in the number of these parasitic nematodes in pink and chum salmon over this 40-year period. And we also dissected cans of sock-eye and coho salmon, but did not find the same. same trend. So in some species of salmon like pink and chum, we're seeing this increase in parasite burden. And is it a lot? Is it like double or triple? It's hard to say. We are still running all of the numbers, but it varies. There are some cans that are worm-free. Of the cans that do have worms, the average is about three worms per can, which you definitely wouldn't notice if you were just the average consumer.

We did have one more recent can that had 115 worms in it. So they can reach pretty big quantities, but that's not typical. Yeah. Well, three is frankly too many. Yeah. Can you tell me if there's like any idea why there's this increase? Is it a bad thing? So there are a couple different possible reasons for this.

One that I think is pretty obvious to me is, that generally in this area, marine mammals have recovered. So in the early 1970s, marine mammals in the U.S. were protected by the Marine Mammal Protection Act. And with that increase in marine mammals, you're increasing the number of definitive hosts for these parasites. So there are more hosts in the environment that can eat these infected fish and release eggs into the environment. It also could be differences in these salmon diet or time spent in marine systems. There might have been a shift in their diets that could have led to an increase in eating prey that are parasitized.

But I think it's probably the marine mammal hypothesis. So it's not an appetizing story, but there's a real silver lining here because it means that mammal species in the waters are rebounding. Yes, that's exactly right. It seems to me like this is kind of a sign of ecosystem recovery. Because these parasites need so many different host species in the environment, if they're doing well, that means that their host species are also doing well. So I think this is actually a good thing.

Well, I'm glad we could get to a happy ending here. Natalie Mastic, she's a PhD candidate at the University of Washington School of Aquatic and Fishery Sciences in Seattle. Thanks so much, Natalie, for taking the time to talk with me today. Thank you so much for having me. Now turning the parasite way back machine to the medieval ages, you might think that the learned friars who lived in the town of Cambridge, scholars with access to innovations like latrines and places to wash their hands, might have lived healthier lives than the common folk.

But a recent study published in the International Journal of Paleo-Pathology says that at least when it comes to intestinal parasites, the friars might have been worse off. Dr. Pierce Mitchell is one of the authors of that paper. He runs the Cambridge Ancient Parasites Laboratory and is a senior research associate in the MacDonald Institute for Archaeological Research at the University of Cambridge.

Welcome, Pierce. Nice to talk to you. So you're talking to me from Cambridge in England. Let's take the clock way back. Can you give me a picture of what the population was like in Cambridge in the medieval times and who was there? The time period that we're looking at when we studied the skeletons for this project, we're looking at about 12, 13th, 14th, 15th century.

And at that time, Cambridge had a population of between 2 and 5,000. And the population was gradually expanding over that time because as the university became more established, more people moved into the town and became a slightly bigger centre. So what were the living conditions like back then? Well, it depends if you were poor or wealthy. So many people in Cambridge would have made part of their living or all their living from farming or from working as a trader or a merchant. Over time, more and more people joined the Cambridge population because of the academic role of the university. But there were also a disproportionately large number of friaries and monasteries and nunneries.

So there was a really big, long list of institutions. The friary that we studied was a studium generale for the Augustinian friars in England. So it was the main centre for academic writing and scholarly manuscript reproduction and so on. So Cambridge was quite a centre for these religious orders. And I know we're really used to sanitising our hands these days, but I guess back then it was a little bit less hygienic? Well, one of the key things is back then they didn't understand about infectious diseases and how diseases were spread, so they didn't see the need for a lot of the things we perceive as good hygiene. They thought that those kind of illnesses were as a result of an imbalance of your four humors. So they felt that if you had normal levels of phlegm, black bile, yellow bile,

and blood, and that they weren't corrupted by any disease process, then that cates you're healthy. So they really didn't understand that washing your hands might protect you from getting infectious diseases or intestinal problems. So you were looking at parasites, and particularly the parasites that these people might have been infected with. Can you say a bit more about how you spotted those parasites? The best way to try and work out how common parasites were are to look at skeletons in the ground and to take the soil from their pelvis where the intestines would have been when they had. these parasites. And then if you look at that soil down the microscope, you can see the microscopic things that are inside there. And while interstinal parasitic worms may be five,

10, 30 centimeters in length, and sometimes many feet in length, the eggs that they produce are tiny, so they may be fractions of a thousandth of a millimeter. So the only way to see those is using microscopy. And those are the ones that lasted in the archaeological record? Right. So the adult worms would die and decompose when their host dies and decomposes in the ground when they're buried. But the parasite eggs are much tougher and so we can find them hundreds of years later. Yum. So you're sampling the dirt from around the remains in the graveyard, specifically around the pelvis of the skeletons. Can you tell us a little bit about what the findings revealed after you did all that analysis? Sure. So we wanted to not just study one population, but to do a comparison.

of different populations who live different lifestyles. So we looked at the burials from a normal Paris cemetery called All Saints by the Castle. And then we compared them with the burials of friars inside the Augustinian friary. And what's special about this particular burial ground is that the friars are actually buried with their habits and their special belts on.

So you can tell which ones are friars and which ones might be members of town who are buried in the friary burial grounds, because you could do that if you paid extra by the fact that they still had their belts. on. So we knew we were definitely dealing with the friars' skeletons themselves. And by comparing those two, we can see is there any difference in parasite infection that might reflect the different lifestyles that the poor peasants in town versus the friars would have actually sustained?

We expected to find that the friars with their nice latrine brock and hand washing and rule of their order, which stressed the nature of hygiene and cleanliness, we expected them to have lower levels of parasite infection than we did in the general public, who many of them were very poor, they may not have even had a cesspit toilet themselves. And what we actually found was that compared with four members of the public, about 32% had intestinal worm infections. In the Augustinian friars, it was 58%. So that's nearly twice the percentage that had these intestinal worms. How surprised were you when you found out this paradoxical result? Well, we thought, crikey, this is not what we were expecting.

So now we had to take a step back and think, what is different about these two groups and the way they live their lives, and what is special about the kind of parasites that were present? The kind of parasites that were present were roundworm and whitworm, and these are spread by poor sanitation. We didn't find parasites that are spread by eating certain meats, like fish tapeworm from eating fish or pork tapeworm from eating pig. So we have to think,

what's special about the life cycle, and how might that fit in with what we know about the medieval period? Now, written sources from the time do talk about how people would fertilise their crops and their gardens with manure from animals, just as people often do today. But it was just as common them to use human feces to fertilise your food and your crops as well. So people would dig out the cesspits when they became full, because someone's got to make the toilet usable again, and then they would fertilize their crops with it. Because they didn't understand about infectious diseases and the fact that worms could be spread with fresh feces,

they would fertilize the crop straight away, rather than manuring it as the World Health Organization recommends today. Because if you manure the feces for a year or so, most of the parasite eggs die and it's much safer to do that. So that might explain why the friars had a higher level of parasite infection than the general public, because if they had a nice latrine block and if they were emptying out their latrines onto their friary gardens once, a year when they were filled up, then that might lead to reinfection of the friars with the parasites that we're seeing. And that might have explained why they had more parasites, the members of the general public who may not have had a toilet at all or may not have been in a position to use their cesspit contents to actually fertilize their own garden.

So what's so interesting to me is that you're studying historical parasites. What is it about these ancient parasites that is going to help us understand our world today? Well, many people are fascinated by our ancestors and the lives they lived and the health that they had, but it also helps us to understand the impact of the modern public health interventions that we take for granted so that now everyone expects that the water that comes out of their tap will be clean and healthy. They expect the food they buy in the supermarket to be clean and ready to eat. Everyone expects their children to survive to be a good age, whereas in the past, people expected most of their children to die before adulthood. So if we can study people who lived before all these public health interventions that we take for granted,

and then show the health consequences among people, and it hopefully reminds modern people, why they should be washing their hands, and why, if they go on holiday to places that don't have such good sanitation, they have to take extra care with the water they drink. They have to make sure they wash their hands, have to make sure they have cooked food rather than salads, because otherwise they will be at risk of getting the kind of parasites that the Augustinian fryers did back in the medieval period. Well, that was really interesting,

and it's all the more reason for us to remember these days to wash our hands, not that we need a reminder. Thank you so much. Lovedy to talk to you. Dr. Pierce Mitchell runs the Cambridge Ancient Parasites Laboratory, and is a senior research associate in the MacDonald Institute for Archaeological Research at the University of Cambridge. Here's Charles Berquist with some folks who helped make this show happen. Emma Gomez and D. Peter Schmidt are our digital producers.

Jordan Smudjik and Jason Rosenberg are our grants managers. Ariel Zitch is our director of audience. Beth Rami is our controller. And I'm radio director Charles Bergquist. Thanks for listening. Thanks, Charles. BJ Leatherman composed our theme music. I was back next week.

I'm Roxanne Camsey.