Science: Gorillas and Heart Disease

Cheryl Lyn Dybas , a freelance science journalist specializing in wildlife biology, marine science and medicine will host an online discussion Monday, Aug. 21 at Noon ET .

For Monday's Science Page feature, Dybas writes about the growing number of captive gorillas who are dying from an unexplained heart condition. Read more in the story: Success Beats in the Heart of a Captive Gorilla .

During her research for the story, she also found interesting correlations of heart disease between gorillas and humans.

The transcript follows.

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Cheryl Lyn Dybas: Hello, everyone, welcome to the noontime science discussion.

Researching and writing this article has been like being a detective in a mystery story.

The heroes and heroines are the scientists trying to solve the puzzle, a young Alabama girl named Sadie Chapman who has a similar disease to the gorillas...and the gorillas themselves.

I'm looking forward to hearing your thoughts on unexplained heart disease in gorillas.

Again, welcome!

Cheryl Lyn Dybas

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Washington, D.C.: How old were all the gorillas who died that you talked about in your article? I had no idea that this was happening to so many of the gorillas in zoos around the country! Thank you.

Cheryl Lyn Dybas: Hello, the gorillas in the article were all in their mid-20s to mid-30s, except for the one female gorilla, Pogo, who was in her late 40s. Most of the gorillas affected are males in their 30s.

Thanks for your question!

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Washington, D.C.: This is odd, I realize, is it true that monkeys peel a banana from the bottom, that is the non stem end. I have asked the national zoo, several forums and no one will answer... please solve this office mystery for us! Thanks

Cheryl Lyn Dybas: Hello, I don't know the full answer to that question, but from what I learned, gorillas, at least, tend to peel away the outer covering of the roots and shoots they eat, and consume the tender interiors.

Hope that helps!

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Washington, D.C.: Question about gorillas. They seem like amazing creatures from watching shows on Discovery channel and others. What was it like to get your first close encounter with one of them?

Cheryl Lyn Dybas: Hi, I watched many gorillas from the borders of their "outdoor gorilla yards," and had a chance to "meet" Babec up close and personal, although with a barrier between us, at the Birmingham Zoo.

In gorilla society, eye contact is minimized with strangers, so I waited to be "invited in" when they came closer to me and met my eyes, out of curiosity. They usually do the same with visitors to zoos around the country, when the visitors approach cautiously and respectfully.

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Wheaton, Ill.: Is the lack of exercise in captive gorillas related to this heart disease like it would be in humans?

What species has the larger heart - gorilla or human?

From Katie and Caroline

Cheryl Lyn Dybas: Hello, lack of exercise might be related to this disease, no one knows for sure. Gorillas in the wild forage for their plant foods for many hours every day. In captivity it's spread around their enclosures so they have to find it, but they don't get the same amount of exercise they would in the wild.

Thanks, Katie and Caroline, for your question!

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Arlington, Va.: Hi, how did Babec and Sadie Chapman first meet?

Cheryl Lyn Dybas: Hi, Sadie, who's 9, was diagnosed with a heart condition when she was small. She read about Babec's heart condition and contacted the Birmingham Zoo and asked to meet him. Zoo officials arranged for the two to meet, and they're now "patient care mates."

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Lake George, N.Y.: How long is the life expectancy of these gorillas?

Cheryl Lyn Dybas: Hello, gorillas in the wild live around 35 years, while those in captivity might reach 50 or even 55. No one knows for sure how long gorillas in the wild live, however, so more study by scientists is needed.

For those in captivity, Pogo, the gorilla who recently died in San Francisco, attained the ripe old age of 49.

Thanks for a great question.

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Annapolis, Md.: Would it be possible for the zookeepers to add Aframomum to the captive gorilla diet and possibly protect the gorillas from heart disease?

Cheryl Lyn Dybas: Hello, great question. Zoos try to feed gorillas in captivity diets as close to the animals' diets in the wild as possible. Aframomum is available outside of Africa mainly as a spice called Grains of Paradise. Interestingly, in this country, one of the main users of that spice is Samuel Adams Brewing Company, which uses it to make its Summer Ale beer.

Aframomum is just one of several native African plants that may antiviral or antibacterial substances in them.

Perhaps this is something zoos could look into further. Scientists are discussing this possibility.

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Hilton Head, S.C.: I am shocked--any indication how long these captive gorilla deaths have been going on? Do zoos communicate this kind of information among themselves? (prior to establishing the specialized database you mentioned). Has anybody tried consulting with botanists to add local ginger relatives or similar antiviral/antibacterial edible plants to captive gorilla diets? Ellen

Cheryl Lyn Dybas: Hello, gorilla deaths from heart disease have been happening for a number of years, although scientists have begun to document these deaths in earnest only in the past decade or more, as they learn more about heart disease not only in gorillas, but in people.

Zoos communicate information, and work together, under something called a Species Survival Plan (SSP), in addition to the National Gorilla Cardiac Database mentioned in the article. Western lowland gorillas have an SSP, under which recommendations for how best to care for gorillas are made.

Veterinarians and cardiologists are discussing ways of solving the heart disease problem in these endangered primates. Looking at the possibility of adding plants from the ginger family is one of the many ideas under consideration.

Thanks for your question!

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Arlington, Va.: Hi, could you talk about how gorilla hearts are similar to or different from human hearts? They're a lot bigger animals than we are, but it sounds like our hearts are very similar.

Cheryl Lyn Dybas: Hi, gorilla hearts and human hearts are actually very similar, although gorilla hearts are larger--because they're bigger animals.

Some cardiologists say that in looking at echocardiograms of these animals, they can't tell a gorilla heart from a human heart on first glance, the hearts are so similar.

Interesting things scientists have found are:

Gorillas have very high cholesterol levels compared to ours, but that doesn't seem to be the reason for their heart disease. Some cardiologists think they may have a different way of processing cholesterol from ours.

Also, heart specialists have discovered that the electrical conduction system in their hearts is actually more advanced than ours, in terms of evolution.

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Annapolis, Md.: Do scientists believe that Aframomum can have application to human health?

Cheryl Lyn Dybas: Hello, no one knows for sure, but it's interesting to think about ways in which plants like Aframomum might have applications to human health...if they do serve as antiviral or antibacterial "drugs" for gorillas, what might be hidden in them that humans could learn from, and possibly develop new drugs from?

Hidden in the African lowlands may be answers to disease for gorillas, and for humans.

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Arlington, Va.: Are these gorillas in breeding programs, and if so, has the genetic factor been considered? Joe

Cheryl Lyn Dybas: Hi, these gorillas are all managed under the SSP, the Species Survival Plan, I mentioned above. Under that plan, gorillas are bred in captivity according to carefully managed plans for the population.

At this time, there are about 375 Western lowland gorillas in captivity in this country; the SSP calls for a total of about 400 to maintain the population in a healthy way.

The "gene factor" is another possibility for why gorillas may be developing heart diseases like cardiomyopathy. There is a particular gene called MMP3 that has links to heart disease, and there are also other genes, currently under study.

Thanks for a great question!

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Bethesda, Md.: Hello, is there a link between all the gorillas in Africa that have died because of the Ebola virus, and these gorilla deaths in the U.S.?

Cheryl Lyn Dybas: Ebola, which is the virus that has caused so many of the gorilla deaths in the wild in Africa, has very different symptoms, like heavy bleeding, from the heart disease that gorillas in captivity are developing.

Captive gorillas' heart disease may well be caused by a virus, but if it is, it might be something like the Coxsackie B virus, which often causes viral cardiomyopathy in people.

This area, viruses, is one in which zoo veterinarians and consulting human cardiologists are very interested.

If heart biopsies are someday done on gorillas, this will give scientists a very good way of determining more information about this unexplained heart disease.

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Annapolis, Md.: Is it possible that gorilla heart disease is caused by a virus and if so, how is it transmitted from gorilla to gorilla and from zoo to zoo?

Cheryl Lyn Dybas: Captive gorillas' heart disease may well be caused by a virus, please see answer above.

If it is, it could possibly be transmitted from zoo to zoo. Scientists who study infectious diseases say that could happen via people (zookeepers who move from zoo to zoo, or visitors who come and go), or by something else that moves from zoo to zoo, like some piece of equipment or various supplies.

But scientists are a long way from knowing for sure what is causing captive gorillas' heart disease. If they discover that a virus is the culprit, then they can begin to look for how that virus could get from place to place.

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Anonymous: If it has been determined that a member of the ginger family is a "potent antibacterial" (natural drug) why is this not incorporated into the captive gorilla's diet. A good source of preventive medicine would seem a solution rather then expensive pacemaker implanted into the gorilla's body. Would the ginger be difficult to grow in this the U.S. and couldn't it be planted in the gorilla's compound and they could graze on it when needed?

Cheryl Lyn Dybas: Hello, you have some great ideas that might work, and which scientists are looking into now.

Studies need to be done to determine which exact plants these substances are coming from (there may be more than one plant, and likely is).

Then, since Western lowland gorillas live in swampy, tropical lowlands in West Africa, botanists would need to figure out ways of either growing the plants here, if that were possible, or getting the "natural drug" compounds from the plants in a form that could be brought here, and still retain the important substances.

In the wild, gorillas strip off the outer coverings of plants and eat them "on the spot." It may be that eating these plants "fresh" is important, no one really knows.

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Bethesda, Md.: I was shocked to instantly recognize the gorilla as I glanced over my husband's shoulder and said, "I know that Gorilla - where is he from?" We moved here from Birmingham almost 15 years ago and had spent many, many hours at the zoo with my young son observing this gorilla and his family behind the glass. I'm saddened to learn of his and other's ill health - as a dietician - I wonder if the lack of Omega-3 fatty acids in the zoo diet contributes to this

Cheryl Lyn Dybas: Hello, the happy news is that Babec is doing very well now, and everyone hopes he will for a long time into the future.

Vitamin E has been one of the things under consideration in captive gorillas diets, along with how much iron they are taking in, and other dietary considerations such as those you mention.

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Bowling Green, Ky.: I am not a physician, so someone please correct me if I state this incorrectly. Aren't there certain bacteria such as histoplasmosis (spelling uncertain) that cause thinning of heart valves, and might it be possible that these bacteria are more prevalent in the human population and the gorillas, when exposed to the human population, become themselves more exposed to such bacteria (or viruses, sorry for not recalling which can damage the heart.)

Cheryl Lyn Dybas: Hello, in humans, there's something called Mitral Valve Prolapse, a very common and usually benign "floppy" heart valve. The mitral valve, if it's a floppy one, can accumulate bacteria and cause something called endocarditis. Some people with Mitral Valve Prolapse need to take antibiotics before they visit the dentist, because of the likelihood of bacteria spreading to the valve.

In times past, rheumatic fever, when it was prevalent, damaged heart valves in people.

In gorillas, since they're prone to dental problems, bacterial infections may be a connection to heart disease, although, again, no one knows for sure.

I don't know the answer to your specific question about histoplasmosis, if there's anyone reading along who does, please let me know and I'll share the answer.

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Bowie: Seeing as the age of these gorillas seems to be a little older than their life expectancy in the wild, is it possible that this disease would be very common in the wild, but gorillas tend to die of other causes before getting it?

Cheryl Lyn Dybas: It'd be great to know the answer to that. Projects that are ongoing in Africa by veterinarians doing research there are looking at the health of Western lowland gorillas. It'll be great when results of that research are known.

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West Orange, N.J.: Apes are mainly vegetarian, yet not known for longevity. Intestinal parasites may kill most in the wild. What kills most in captivity? Lack of exercise? How do their cholesterol and arterial plaque levels compare to those in humans? Any lessons on cause and effect?

Cheryl Lyn Dybas: Gorillas' cholesterol levels are very high, but this doesn't seem to affect them in the same ways it would us.

Their arterial plaque levels, in spite of that high cholesterol, are very low, so they must have some way of processing cholesterol.

Scientists have found that gorillas have high amounts of LDL, the "bad" cholesterol, and low amounts of HDL, the "good" cholesterol, but when veterinarians do autopsies on gorillas who have died, they don't find much, if any, plaque in gorillas' arteries.

More of the mystery.

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Arlington, Va.: This is very important research that could also benefit humans. Has research been done on the human heart and it's potential benefit from Aframomum? The gorilla's could teach us something!! Judy

Cheryl Lyn Dybas: Hello, I'm not sure of the answer to that, although it's a very intriguing question! Maybe we all should be eating "Grains of Paradise," who knows? Gorillas and humans can definitely teach each other something, especially about heart disease.

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Rockville, Md.: I can see how heart disease has roots in our behavior. It is a recent disease as they go and was once called "the doctor's disease." How can we fix things?

Cheryl Lyn Dybas: Hello, I'm not sure we'll know how to fix this, until we know why it's happening. Basic biological and biomedical research by scientists is the key: without that basic understanding of what's happening, we won't know how best to treat the disease.

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Rockville, Md.: I know it's not always feasible, but are the gorillas being maintained in captivity in group sizes that are similar to those in the wild? Stress due to less-ideal troupe sizes and therefore fewer social contacts?

Cheryl Lyn Dybas: Gorillas in captivity are indeed maintained in group sizes very similar to those in the wild. If anything, in captivity, gorillas probably have more social contacts than fewer, as they are together in smaller spaces than in the spread-out lowlands of Africa.

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Arlington, Va.: Your answer to the question about virus, and the possibility of this having come from zoo-keepers, makes me wonder if there have been any studies of the human populations in the same area to determine if they suffer from the same disease. Joe

Cheryl Lyn Dybas: That sounds like an interesting idea. As far as I know, no such studies have yet been undertaken, in terms of correlating fibrosing cardiomyopathy in gorillas and humans in the same general area.

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Turmeric?: I found that plant you mentioned interesting. Turmeric, a root, is used in Indian folk medicine and has similar anti-inflammatory properties, and is widely available in America. Human populations with the highest turmeric consumption also have the lowest incidence of Alzheimer's. What are the thoughts of trying and adding turmeric to gorilla diets, pending actual ability to cultivate said natural gorilla medicine plant?

Cheryl Lyn Dybas: I haven't heard of tumeric in relation to captive gorillas, but it's another plant that scientists should perhaps investigate...

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Silver Spring, Md.: What percentage of the captive population that are old enough to reproduce do these deaths represent? How will the deaths impact the ability of the captive gorilla population to maintain itself?

Cheryl Lyn Dybas: I'm not sure what percent of the captive population these deaths represent, but thus far, the deaths don't seem to have impacted the population's ability to maintain itself.

The gorilla SSP I mentioned earlier, and those who manage the SSP, keep careful track of captive gorilla population numbers.

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Hypercholesteremia?: Has the issue of hypothyroidism been studied in gorillas? Many things in America (PVC, phalates, perchlorate) etc. can cause hypothyroidism, as well as the lack of iodine in their diet. The EPA water safety standards are based on humans, and even these may need to be revised to make drinking water safer in terms of perchlorate. Dog hypothyroidism is also at a high in the US and I'm not certain that is genetic, when I see my dog drink twice the water I do when he's half the weight. I filter our drinking water. Both hyperthyroidism and hypothyroidism can affect heart disease. The peridontal disease, though, makes me think of hypothyroidism. I developed early stage peridontal disease when I was untreated for hypothyroidism. After I returned to normal levels, a year or so later I saw my dentist and he denied I had any sign of gum disease, and my mouth did look better then.

Cheryl Lyn Dybas: Hello, I'm not sure whether hypothyroidism is on the list of things being studied in captive gorillas, although I think that is likely being looked at in blood tests done on a routine basis. Your own history sounds of interest to those reading this.

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Silver Spring, Md.: Hi, Do you track this problem globally in Zoo's around the world or just in the US? In Berlin/Germany right now one of our Gorilla Lady "Fatou" seem to die of the same problem. Poor thing has lost already 30 kg in a very short amount of time and it looks like she is not going to live much longer, she is 51 years old. Will maybe a global exchange program for breeding help, if the cause is genetic?

Cheryl Lyn Dybas: Hello, I'm sorry to hear about Lady Fatou.

Although this article looked primarily at captive Western lowland gorillas in the United States, I've heard that the same problem exists on a worldwide basis, so whatever process is causing heart disease in captive gorillas, is likely present in captive populations in the U.S., Europe, and elsewhere.

Perhaps that's a clue.

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Cheryl Lyn Dybas: One of the main issues is the importance of studying gorillas as a population to understand the scientific principles at work, say researchers who specialize in infectious diseases, cardiology, and related areas.

Many people have asked about whether this cardiac disease, if viral, could "spread" to humans.

There's still some distance to go before there is a proven cause-and-effect between any viral infection/disease in gorillas, so it would be very premature to worry about this finding its way to humans, scientists say.

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Cheryl Lyn Dybas: We're unfortunately out of time for this Post on-line discussion today.

Thanks so much to all of you for participating, and for your interesting questions and thoughts on gorillas and heart disease.

Hopefully scientists will soon find the answer to this mystery.

Thanks again!

Cheryl Lyn Dybas

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