More Science Talk
Some veterinarians treat animals much more exotic than the family pet. Jeffrey Boehm, executive director of the Marine Mammal Center, talks about the challenges of caring for sick sea mammals. And Alisa "Harley" Newton, a pathologist with the Wildlife Conservation Society, discusses how vets figured out that a pathogen attacking humans was in fact West Nile Virus. Plus, we'll test your knowledge of some recent science in the news. Web sites related to this episode include www.tmmc.org; www.wcs.org
Steve: Welcome to Science Talk, the weekly podcast of Scientific American for the seven days starting November 19th 2008. I am Steve Mirsky. This week we'll hear from a couple of veterinarians who deal with animals a bit more exotic than the family pet. Jeffrey Boehm runs the Marine Mammal Center in Sausalito, California, and Alisa "Harley" Newton is a pathologist with the Wildlife Conservation Society's Global Health Program. Plus, we will test your knowledge about some recent science in the news. Jeffrey Boehm recently became the executive director of the Marine Mammal Center which will be featured on an episode of NOVA that airs November 25th. He spent 16 years at the Shedd aquarium in Chicago where he was senior vice president of animal health and conservation science. Boehm was passing through New York this week and dropped by Scientific American.
Steve: Dr. Boehm; great to talk to you today.
Boehm: It's excellent to be here, Steve.
Steve: Tell me about the Marine Mammal Center: What is it, what you do?
Boehm: The Marine Mammal Center is, in basic terms, a hospital for distressed, sick, injured, seals and sea lions along the central California coast.
Steve: And there are tons of them.
Boehm: Well, there are plenty. We've typically 600 or so patients a year; [the] high-water mark, if you will, is about 1,200 patients that we saw one year back in 1998. But year
and [in], year out, we are seeing patients coming in from literally year around, but we start to see an influx in the late winter months, early spring months, all throughout the summer starting to decline a little bit coming fall.
Steve: When you say, you see patients coming in, I have heard of stories where somehow the word gets out, the animal community and there is some kind of rehab center and some of them just start showing up when they are sick.
Boehm: They are lining up with their medical card...
Steve: But how do most of them wind up there?
Boehm: Right, right, it's a great question. So, if you imagine anyone who is on a beach or at a marina or at a wharf, who happens to see a California sea lion or a harbor seal. We are centered in Sausalito, so if you think 100 or rather 300 miles north and 300 miles south of us, so up to Mendocino county and down to San Luis Obispo county, lots of coast, lots of buried coastline. So they are very populated areas, very rugged, very raw areas, but people encounter these animals commonly. Often they are encountering perfectly healthy animals but from time to time they are seeing an animal that clearly is in distress or to their mind need[s] some attention, and that's where we start to get involved. Typically, what we will do is we will avail ourselves of our 800-person volunteer crew; this is a phenomenal number of people who are committed to working with us, often in these remote locations, and they will be our first responders. They will get out there and get their eyes on the animal. Often, what we need to do is just monitor that animal; and as we get more and more friendly with our coastlines, we are finding ourselves overlapping with the communities of these wild animals more and more. So, these close encounters happen often. Typically a situation will occur where we just need to watch the animal, it will get back into the ocean and will find its way back to its (unclear 3:13) or back to an area that's a little more remote on its own. But if we need to, we have vehicles that we can deploy, safely pick the animal off the beach and then bring it to the Sausalito Hospital. On its way, if it's in the southern part of our range, it may stop at San Luis Obispo or at Moss Landing in Monterey County where we have two triage centers with staff and volunteers, but the whole focus is providing the best care for that animal. As I say sometimes the best care is just monitoring it, but sometimes these animals really do need a hospital setting, and that's when we bring them into the center in Sausalito.
Steve: Real quickly—[the] difference between seals and sea lions: ears are in there, what is it for people?
Boehm: The easiest thing—and this is hokey to say, but—the easiest thing for me is to have people imagine those story books from when they were a kid or that zoo encounter where you see a seal with a ball on its nose—that's typically a California sea lion that people will bring to mind. So that isn't eared, a sea lion. The distinguishing characteristics are the long fore flippers, the ability for those animals to rotate their hips up underneath them and actually walk on all fours.
Boehm: The elephant seals, the harbor seals that we see don't have that external ear flap and they also tend to angulate along on the their bellies more than to come up on all fours.
Steve: Because they probably can't; they're so huge.
Boehm: Well, it's size but it's also just morphometrics and morphology, I should say. So they just don't have the ability to come up on all fours. They have short, more stubby fore flippers and don't have the agility that a California sea lion or a stellar sea lion would have.
Steve: Now you mentioned the classic image of the sea lion balancing the ball, but that brings up the point that these are really intelligent animals. So what is it like working with these animals in a physician-patient relationship, when, you know, they can't really communicate but they are much smarter than most animals that most vets are dealing with.
Boehm: Yeah, I have an interesting perspective on this because I've trained as a vet but I also went into a veterinary school, worked at an aquarium at Sea World in San Diego. So I trained sea lions as well, and I can tell you, they are bright, they are wily, quite intelligent animals; and it's a fascinating piece of the puzzle but it's also a little bit of a challenge for us in the rehabilitation community. Sea lions—specifically the California sea lions and the stellar sea lions that we see—have a tendency to habituate really quickly. So as you discuss kind of the physician-patient relationship, that's the relationship that we really want to manage quite carefully with those species. The problem is that they get so familiar with us and they put two and two together quickly and they realize that this is not a bad deal: These folks are niece, they are friendly, they are coming in with buckets of fish ...
Steve: I mean, that's why they are so easy to train.
Boehm: This is an easy lay, and so if our success story is taking these animals in, appropriately caring for them and then bringing them back out into the ocean and releasing them. [It] get[s] hampered when this relationship gets strong and when they make these connections too well, so they find themselves up on beaches poking their noses into picnic baskets or more detrimentally following fishing boats where they run into all kinds of problems. So we have this kind of repeat offender, a fact where we will take in—classically we tend to see as an example, California sea lion yearlings. So natural history there is that mom will give birth, she will nurse that sea lion pup, when he is three, four or five months old, he will start decreasing his nursing and fishing on his own; come to the one-year birthday mark, she has been pregnant, she is delivering the next year's pup. She boots the first one out and that animal is either ready to fare well on its own or not. If not they tend to come into a facility like ours. And at that age, we tend to see often these animals imprinting or habituating in a profound way and within three weeks time—this past summer we had one animal come back to us three times—and they get to a point where they are simply not releasable and that's not a success story for us. Ultimately, we find appropriate homes for those animals but sadly the appropriate home in that case is not the wild.
Steve: The study of what's going on with these animals has to have some kind of a larger context that means
when if you are seeing these sick animals that must be a sign of some kind of environmental issue.
Boehm: Yeah. The way we tend to put it is that our first focus is the patient, the individual. What's going on with this animal, how [can]
come we address its need in the most humane way. Hopefully, carrying forward and releasing it, sometimes not; stepping back from that a level does need an enormous amount that we advance in the realm of science by working with these animals. And in simplest terms, we are amassing data on what is normal and what is abnormal for these animals. The Marine Mammal Center has been in existence since 1975 and we have a decade's long collection of samples in our tissue bank. So we have blood samples, we have tissue samples that go back decades. That's a resource for scientists in the future, the needs of what [which] we don't even know yet; but it is going to be a great library, [a] great resource for us. Right now we are learning things every year as we work with these animals. We are seeing syndromes emerge, we are seeing diseases manifest and we are starting to try to understand what's presented to us in this one patient, how it fits into what's going on with the population and how that population fits into the bigger environment. And the fascinating thing for many of us is that we are finding that that ultimate question surfaces a lot of connections between people and that environment. Not surprising when you think about it: I mean, we are all reliant upon a healthy planet, healthy oceans, we rely on the same fisheries that these seals and sea lions rely upon. So some of the diseases that manifest in these animals that solely eat fish, [we] would be wise to watch these and to follow them to see if there is any hint of an impact on us—the selfish argument—but also an impact on the environment in a more general sense and more altruistic and a bigger picture we are looking at.
Steve: Let's talk about some of the specific diseases you are seeing—this domoic acid situation. What is that?
Boehm: What occurs is that, as normally present algae matures,]
elaborates [it creates] a toxin—domoic acid; why we don't know, but it's present. As small animals ingest that algae, they ingest that toxin, doesn't appear to have any ill effect on them. Small fish then consume those smaller animals, whether that would be fish or crustaceans whatever they might be, and it goes up in the food chain in the biomagnification kind of process.
Steve: So it is getting concentrated at much higher levels than in the original algae.
Boehm: Exactly, so you see a top predator like a sea lion relying on these fishes, its sole food source, and they can sometimes be getting significant loads of these toxin. This first became evident to us back in the late '90s when we saw this enormous influx of animals present to us but also an array of signs and symptoms that were dramatically different than what the center had seen in the years prior. Primarily seizure activity, some abortion from pregnant animals that were aborting fetuses, and as we started to look into it, this whole syndrome of this domoic acid toxicity became apparent. What happens is that the toxin mimics a normal neurotransmitter in the brain, where the receptors
are for that neurotransmitter happen to be really focused in a concentrated way in the part of the brain that has to do with mental mapping, the hippocampus. And over years—this is many years and many cases of looking at this—we are finding that there is chronic changes to the brain of this [these] California sea lions that implies damage to the hippocampus and leaves these animals unable to navigate out in the wild. Best example was an animal that had chronic domoic acid poisoning; [it] was released and had a satellite tag on it. These are animals that come up on the shore and rest in (unclear 12:03) overnight. This animal made a beeline towards the Hawaiian Islands, not a normal behavior for these animals; notorious in our part of the country, our stories of California sea lions appearing upriver in small towns that [where they] have no business being—very notorious—and the animal took up residence on top of a California highway patrol car. It's a bit comical but it's obviously tragic. The same toxin is something that affects people and it's amnestic sea food poisoning. We are not typically ingesting fish with the frequency, with the volume, that a California sea lion is, but we are in an organization like many of our peers that collaborate extensively. Some of our collaborators ran something like this— are MD neurologists who are interested in understanding the impact of this toxin on the brain, understanding seizure activity in sea lions—and so a wealth of studies has been spawned by this as we try to get a handle on what's going on out in the ocean, what's changing. Was this occurring in great numbers before we were watching? How do we understand what the implications are as we look to the future and what are the reasons that this algae might be growing in a more prodigious way now compared to decades ago? And if you look at the nutrient loading from, you know, a heavily agricultural state and the effluent going out into the ocean, what is that changing in the dynamic? What are the, kind of, the epidemiologic factors at the individual? Where are we seeing these animals show up? Is it hitting specific gender, you know, one gender more than another, one age class more than another? All of these questions are answered by keeping meticulous records and looking at these things longterm over many years. But that just is one disease entity that we tend to see. Another interest, especially as we draw the line and connect a dot between these animals and humans is an incidence of cancer in California sea lions, so close to 18 percent, it is under 20 percent, of the adult California sea lions that we look at postmortem. So it's a, you know, small class of the animals within the population, the animals that we see. We have seen an incident of cancer, urogenital cancer, and what happens is that that tumor grows and then spreads to the lymph nodes in the region, eventually paralyzing the animal and leading to its stranding on the one hand, but certainly it's dead. This is a situation where when I talk about our rate of success, an animal like that that comes into the center is one that we will pretty quickly diagnose, make the decision to humanely use knives. But why are they getting this cancer and again have they been, is this study state or is this an uptake in the incidence of this cancer in these animals? Are there genetic factors that contribute to this? Are their levels of toxins, PCBs, etc., in their bladder that might help us understand a correlation between pollution and cancer in these animals?
Steve: Any leads yet on why the frequency is so great?
Boehm: Well, the suspicion now is that there is a link between the exposure to pollutants and the cancer but it is, again, it's a bit speculative and
that's [there's] a chance that, you know well of studies like this that are basically playing out dependent on animals that we encounter, so it's years before we are able to see a really clear picture emerge. But is there a genetic predisposition among the species or any other factors that might have contributed to it? We are still looking at that.
Steve: Well, these are not, most of these species [that you're dealing with] are not in danger. So what's the big picture:
of Why do this work at all? If these individuals can't make it, the species still [survives].
Boehm: Right, excellent point. At the Marine Mammal Center we see California sea lions, harbor seals and elephant seals—while elephant seals have declined decades ago they are doing really well now. So, from a population number point of view, we see a lot of problems out there, but their population numbers are sustained fairly well. And so the obvious question is why you are putting all this effort into it, and the answer is in three parts. First of all, it's the right thing to do and it's the humane response, it's the ethical thing to do. When you see an animal in need we provide a place, [and] second, address that need. Beyond that though, the information that we gain from a scientific point of view by assessing these animals, collecting data, sharing that data in scientific journals, in publications is tremendous and in an organization like ours that has really made a mark on advancing the clinical care of these animals but also the scientific research. Finally, by working with all of these animals that do have robust numbers, we learn a lot that we can apply to species that aren't in such a great shape. And two prime examples certainly on the west coast and into the Hawaiian Islands is the stellar sea lion population which is further up the coast from us, more typically on the west coast of North America, [a] population of animals that's in great decline. The California sea lion is an excellent model for that. So the work that we do [and have done for decades] is California sea lions [and that] informs our work with stellar sea lion pups. We are releasing every individual and it really does make a difference, not just obviously for that individual but for the population. The Hawaiian monk seal in the Hawaiian Islands is a population that stand[s] at about 1,100 animals. We currently have volunteers that are working in Hawaii with a pup this year right now and that work that we we're doing with a Hawaii monk seal pup we wouldn't be able to do had we not had decades of experience with elephant seal pups and Harbor seal pups, understanding what their nutritional needs are in the early weeks as they mature and ultimately taking them off of formula and putting them on to solid food. We have got a great expertise in that that we are able to share, but none of that would be possible if we weren't doing this work with kind of the bread and butter patients that we see.
Steve: For more on the Marine Mammal Center visit www.tmmc.org. The PBS program NOVA features the center on their November 25th episode called "Ocean Animal Emergency". The center has a new hospital opening in June 2009 which will include a necropsy room visible to the public. The necropsy is an animal autopsy. So it's a rare opportunity to see wildlife pathologists at work.
Steve: Alisa "Harley" Newton is a wildlife pathologist with the Wildlife Conservation Society. She is based at the Bronx Zoo and gave a public talk on November 6th about how wildlife vets unraveled a human disease mystery. Here's part of that talk.
Alisa: The WCS is really dedicated to the health and well being of wildlife both here in our collections and abroad and while we work in many ways to protect wildlife, one of our really critical roles is as disease investigators. And I am a pathologist and usually when I am asked to describe my job, I tell people, it's like CSI: Bronx Zoo.
Alisa: You know, we are disease detectives. It's just that, you know, our criminals are very, very smart. And this has led to some really exciting disease discoveries in the 21st century. One of these discoveries actually came just because of our role as disease investigators for the living institutions, which is the four zoos and the aquarium here. One of our jobs is to investigate the death of any wildlife that we find on zoo grounds, and we do this for a number of reasons. We do this to protect the animals that are in our collection. We do this to protect the health of the people who come and visit our zoos, and we also do it to, sort of, keep ourselves in contact with what kind of diseases are important to New York wildlife. And as many of you will remember in the late fall of 1999, there was a disease outbreak that began here in New York City. For us it began in the city zoos and particularly the Queen[s] Zoo, where they were finding lots of dead crows on zoo grounds. But it didn't actually stop there. Over the next few weeks, from August through September, 27 wild and exotic captive birds either became ill or were found dead and these were birds from eight different orders and 14 different species, and most of the animals that were sick ahead of time showed neurologic signs. So there was clearly something wrong with their brain. When we took tissues, what we saw was really severe inflammation. All of these birds had this, and they had encephalitis. So here is what's interesting. At the same time that we had all these birds die of encephalitis there were a lot of really sick humans in New York City who were also suffering from encephalitis
and [that] had been identified as St. Louis encephalitis. So that of course begs the question while we cut [had] all of these sick birds and all of these sick humans: Is it the same thing? The trouble is that the species that we were seeing sick, the species of birds don't get St. Louis encephalitis. So either we had two viruses running a mark [amok] in New York City that causes sort of the same symptoms or their identification of St. Louis encephalitis was actually incorrect. Tracey McNamara was the head of pathology at that time, and she was absolutely convinced that the birds and the humans had to have the same disease, and actually with the help of the Army, who supplied us with this lovely biosafety cabinet which is always wonderful when you are dealing with some new virus that you have no idea what it is going to be, really took this investigation to the next level. And what she did is she submitted our samples to have the virus cultured and then to have it genetically identified, and when you have those moments on those crime shows where they say, "Well, you left your DNA behind at the crime scene," so this was the criminal that was responsible for the deaths in all of our birds and that was West Nile virus. As soon as we made this identification, samples from the humans were actually taken from New York City were compared to the virus that we had isolated at the zoo and that's when they found that that they were the same virus and that this identification of St. Louis encephalitis had actually been incorrect. So this is a really critical discovery for us, for wildlife, because clearly this wildlife species that are [is] excruciatingly sensitive to this virus and it could potentially affect the population. Obviously this was a really critical discovery for humans—West Nile virus had never been seen in the Western Hemisphere before we identified it here in New York City. It was also important to domestic animals. The virus that we isolated from a flamingo at the Bronx zoo was actually used by Fort Dodge to create the animal vaccine for West Nile virus. So any of you who vaccinate horses for West Nile virus, it was generated from the virus that we found in our flamingos at the zoo. This also just demonstrates sort of the critical role that wildlife disease surveillance can, even on a basic level, can have on the health of all of us. Because it was only through this routine surveillance that we found this virus when it first emerged right here in New York City. The overlap between animal health and human health is actually, it's quite great.
Steve: Now it's time to play TOTALL....... Y BOGUS. Here are four science stories; only three are true. See if you know which story is TOTALL....... Y BOGUS.
Story number 1: The new animal leaping champion is the spittle bug, found to be able to jump 100 body lengths.
Story number 2: After almost being wiped out a century ago, over half a million bison now roam free across the U.S.
Story number 3: Solar power, meet shade conservation. A study finds that having less than 20 percent of a house in heavy shade can cut electricity usage by more than 10 percent.
And story number 4: Some of the compounds in marijuana may actually help memory.
Time is up.
Story number 4 is true. Ohio state researchers think that specific compounds in pot can be good for the aging brain by reducing inflammation and possibly even stimulating the formation of new brains cells. They presented these findings on November 19th at the Society for Neuroscience meeting in Washington, D.C. Alzheimer's disease appears in part due to inflammation. So the development of legal drugs for dementia could come out of marijuana research. Marijuana's THC thus joins nicotine, alcohol and caffeine as agents that have shown some protection against inflammation in the brain that might translate to better memory late in life.
Story number 3 is true. Researcher David Laband of the Auburn University School of Forestry and Wildlife Sciences found that heavy shade coverage on just 17.5 percent of a house could cut electricity usage in cost by 11.4 percent; that's compared to a house with no shade. Late afternoon shade and heavy foliage are the house keys to cost cutting.
And story number 1 is true. The spittle bug can jump 70 centimeters, which equals about 100 body lengths, better than a flea. The finding was published online in the journal, BMC Biology. The insects use a catapult mechanism; the slow contraction of a big bank of muscles stores energy in an elastic internal structure which is then released in less than a millisecond to power the explosive extension of the hind legs. [The] spittle bug's previous claim to fame was the ability to blow bubbles out of its rear end.
All of which means that story number 2, about half a million bison roaming free in America is TOTALL...... Y BOGUS. We do have half a million bison, but almost all of them are on ranches, just 16,000 free ranging bison live in North America. The Wildlife Conservation Society wants to up those numbers in part in a way that may surprise you. Kent Redford is vice president for a conservation strategy at the WCS, and he says "One road to bison conservation may be a pragmatic market based approach, namely to grow sustainable markets for wild free ranging bison meat." So for your next barbecue try some bison—tastes great and it's good for them, well, some of them.
Well that's it for this edition of Scientific American's Science Talk. Visit www.SciAm.com for all the latest science news, videos and our family of podcasts including 60-Second Psych and 60-Second Earth. For Science Talk, I'm Steve Mirsky. Thanks for clicking on us.