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http://www.livescience.com/animals/080406-ap-ape-disease.html

Deadly Ape Heart Disease Puzzles Zoos

By Todd Lewan, Associated Press

posted: 06 April 2008 10:00 am ET

Mopie looked the picture of ape fitness: His shoulders were broad and
imposing, his silver-haired back sculpted and muscular, his biceps
bulging as wide as a wrestler's thighs when he scratched his head.

He had a healthy appetite (he'd put away 7 pounds of food daily) and
Mopie was no couch gorilla, either: He'd nimbly scale the mesh of his
enclosures at the National Zoo in Washington, D.C., playfully chase
the younger gorillas, and perch himself high in an outdoor maple, as
if to show the world he was the king of the Great Ape House.

"The unique thing about Mopie was how extremely handsome he was," says
Lisa Stevens, curator of primates and giant pandas at the National
Zoo, and whenever the silverback sat, proudly, in the exhibit's trees,
"it just added to his impressiveness."

Which is why Stevens and the zoo's staff were so stunned when, on the
afternoon of July 3, 2006, this prized western lowland gorilla
suddenly collapsed after playing with some newly introduced mates. By
the time the keepers cleared out the other gorillas and tried CPR on
Mopie, the gentle, 430-pound giant was lifeless - a victim of heart
failure at 34.

Like his father, who had died the same way at the zoo in the early
1990s, Mopie had previously been diagnosed with an unexplained form of
heart disease known as fibrosing cardiomyopathy, in which healthy
heart muscle turns into fibrous bands unable to pump blood. And yet,
he had not shown any outward symptoms, and his diet and behavior were
normal.

"There was nothing to indicate he was feeling poorly or under the
weather," recalls Stevens. "That's what made it even more of a shock."

No less troubling, two days earlier the National Zoo had lost its only
other male group leader, a silverback named Kuja. Diagnosed just a
month earlier with congestive heart failure related to cardiomyopathy,
Kuja (pronounced KOO-yah) died while undergoing surgery to receive an
advanced pacemaker. He was 23.

Sadly, Mopie and Kuja were not alone.

Gorillas in zoos around the nation, particularly males and those in
their 20s and 30s, have been falling ill - and sometimes dying
suddenly - from progressive heart ailments ranging from aneurisms to
valvular disease to cardiomyopathy.

Just two months before the deaths at the National Zoo, the San
Francisco Zoo had lost a lowland gorilla named Pogo to heart disease.
A week before that, the Memphis Zoo lost one named Tumai the same way.
And in previous years, there were others: Akbar at the Toledo Zoo in
2005, and in 2000 both Sam at the Knoxville Zoo and Michael at the
Gorilla Foundation in California.

Now zookeepers are scrambling to understand what factors may be
causing the illnesses and what might be done to save the 368 lowland
gorillas that currently reside in 52 zoos across North America.

A 1994 study of 74 captive gorilla deaths, published by veterinarians
Tom Meehan of the Brookfield Zoo in Chicago and Linda Lowenstine of
the University of California at Davis, found that 41 percent - and 70
percent of males older than 30 - were from heart disease, mainly
fibrosing cardiomyopathy.

"That study was a wake up call," says Meehan, now the vice president
for veterinary services at the Chicago Zoological Society. It showed
the need to "go to the next level of evaluating the animals and
figuring out how their lifestyle related to their health."

In the mid-1990s, when the study was published, about 100,000 western
lowland gorillas roamed freely within vast forests in Cameroon, the
Central African Republic, the Republic of Congo, Equatorial Guinea,
Gabon, Angola and Nigeria. Far less endangered than their relatives,
the mountain gorillas, these apes were officially considered only as
"vulnerable."

Since then, however, lowland gorillas in the wild have been dying at
an accelerating rate. Poaching, logging, a dramatic expansion in the
trade of bushmeat, and outbreaks of Ebola have reduced their numbers
to roughly 30,000 - and in September, the species was reclassified as
"critically endangered." At their current rate of decline, the
gorillas are projected to disappear from the wild by 2050.

"Soon, these great apes may only exist in captivity," says Haley
Murphy, director of veterinary services at Zoo New England, which runs
Boston's Franklin Park Zoo and the Stone Zoo in Stoneham, Mass. The
zoos are home to seven western lowland gorillas, the only species kept
in captivity.

In 2000, Murphy, together with Dr. Ilana Kutinsky, a cardiologist with
the Michigan Heart Group, began reviewing cardiac ultrasounds of zoo
gorillas in hopes of discovering why the animals were at risk for
heart trouble. It was part of a broad, veterinary detective effort to
help save what Murphy calls "our closest living relatives,
evolutionarily."

Problem was, no one had defined how a normal gorilla heart operated.

But as ultrasound information was entered into a database and compared
to necropsy reports on deceased gorillas, clues began to appear. "We
started noticing that some gorilla hearts were grossly abnormal from
others," Kutinsky says. "The abnormal ones were mildly enlarged, very
thick, and weren't pumping as much blood."

The findings raised more questions: Were the heart abnormalities the
result of genetic differences? The gorilla's sex? Did climate play a
role? How big a factor was diet? Were the gorillas getting enough
exercise in their enclosures? Or too much? Was heart disease being
caused by bacterial or viral infections?

Some even asked: Were gorillas developing heart disease because of the
way they were reared or socially grouped at the zoos?

As the scope of the mystery widened, the number of cases of apes
developing heart problems steadily climbed.

One was Babec, a 24-year-old lowland gorilla at the Birmingham Zoo in
Alabama. Male gorillas in zoos have lived to age 54, and median life
expectancy is 30; so when Babec started coughing, eating less and
clutching at his chest in early 2003, the staff veterinarians examined
him, and identified his nemesis: cardiomyopathy.

Although the gorilla was given medications for heart disease in
humans, his condition kept deteriorating. He lost 80 pounds (20
percent of his body weight), was accumulating fluid in his abdomen.
And by the summer of 2004, his heart pumped just 10 percent of the
blood his body needed.

With Babec in the final stage of heart failure, the zoo risked a
procedure never before attempted on a gorilla: the implantation in
Babec's chest of an advanced pacemaker that corrects the heart's
electrical circuitry and restores its ability to contract properly.

Today, Babec's prognosis is excellent. He's dropped the excess water
weight, his heart and other organs work more efficiently, and his
heart and pacemaker are continuously monitored.

Neal Kay, a cardiologist at the University of Alabama at Birmingham's
Heart and Vascular Center who volunteered to perform the operation,
later remarked that the only reason Babec still greets visitors to the
Birmingham Zoo is that "we got to him in time."

Such intervention could save individuals like Babec - but still
largely unaddressed were questions of why gorillas develop heart
disease in the first place, and how to halt the disease's progression.

That's why in November 2006 - three months after Mopie and Kuja died
at the National Zoo - ape experts, human cardiologists, and zoo
epidemiologists, pathologists and managers from around the country
gathered at the Brookfield Zoo in Chicago to establish what they
called the "Gorilla Health Project."

Their first task: To build a National Gorilla Cardiac Database. With
it, veterinarians could track rates of heart disease and death and try
to learn why scar tissue was replacing cardiac muscle in apes.

To Kristen Lukas, chair of the Gorilla Species Survival Plan for the
Association of Zoos and Aquariums, the project marks "a sea change" in
how zoos will care not only for gorillas, but a host of other
endangered species in captivity.

This level of networking between veterinary and human medical experts
from universities, hospitals and animals rights groups "just never
happened before," she says.

Meehan, the Chicago veterinarian who has worked with gorillas since
1979, expects the initiative to bring animal care forward a quantum
leap from, say, the 1960s, when gorillas were originally brought to
North American zoos and staff struggled just to keep the captive
population alive.

Gathering new data will present challenges, of course. One is the need
for echocardiograms of apes. To do the test, a gorilla must be
anesthetized, "which carries a certain amount of risk," says
cardiologist David Liang of Stanford University, a consultant to the
Gorilla Foundation in California.

Another option, some experts say, might be to perform biopsies on
affected gorillas to obtain tiny samples of heart muscle. This, too,
would require anesthesia.

Many primatologists and veterinarians consider diet a prime suspect of
heart disease in captive animals. And exploring that may require
extensive study of the mortality of western lowland gorillas in the
wild, they say - which, for many reasons, is tricky.

Gorillas in the wild tend to die younger, meaning not as many live
long enough for age-related disorders to show up. Moreover, male
silverbacks - the king of gorilla society - often hide symptoms of
illness because they fear they may be challenged by younger males.

Still, research in the wild has paid off before. Not long ago, for
example, it was learned that lowland gorillas, which are primarily
herbivores, wade into swampy lake areas and eat vegetation growing
underwater.

"There was no way of knowing that sort of thing was happening until
somebody went out there to Africa and noticed what the gorillas were
doing," says primatologist Joseph Erwin of the Foundation for
Comparative and Conservation Biology in Needmore, Pa.

Ellen Dierenfeld, a gorilla nutritionist at the St. Louis Zoo, says
that a member of the ginger family, Aframomum melegueta, is a staple
food of western lowland gorillas in their native environments.

Some scientists say Aframomum is a powerful antibacterial, antiviral,
antifungal and anti-inflammatory "natural drug," which may serve as a
preventive medicine for the gorillas. But this and other native
African plants are often not part of zoo gorillas' daily diets.

The Gorilla Health Project's diet and other data should be gathered by
early 2009, analyzed and shared later that year, says Pam Dennis, a
veterinarian in charge of analyzing the information.

"The important thing is that we're now working to prevent the diseases
in the first place," says Dennis, an epidemiologist with the Cleveland
Metroparks Zoo and Ohio State University.

"We started out trying to figure out human health by studying animals.
Now we're turning to our findings in humans to figure out how to treat
animals," she says with a chuckle. "It's come full circle, which is
sort of a beautiful thing."