Success Beats in the Heart of a Captive Gorilla
Monday, August 21, 2006
BIRMINGHAM, Ala. -- Gorilla gorilla gorilla .
The scientific name of the endangered western lowland gorilla echoes like a cry for help.
Adult western lowland gorillas in captivity are dying of an unexplained heart condition called fibrosing cardiomyopathy, which turns healthy heart muscle into fibrous bands unable to pump blood. The condition is similar to a human form of heart disease.
No one has kept track of exactly how many captive gorillas have succumbed, but veterinarians Tom Meehan of the Brookfield Zoo in Chicago and Linda Lowenstine of the University of California at Davis calculated that 41 percent of deaths of captive gorillas -- and 70 percent of deaths of the males older than 30 -- are the result of heart disease, primarily fibrosing cardiomyopathy.
The toll includes Mopie, National Zoo, July 3; Kuja, National Zoo, July 1; Pogo, San Francisco Zoo, May 24; Tumai, Memphis Zoo, May 18; Akbar, Toledo Zoo, Dec. 6, 2005; Sam, Knoxville Zoo, Nov. 17, 2000; Michael, the Gorilla Foundation in California, April 19, 2000.
Babec, a western lowland gorilla at Alabama's Birmingham Zoo, is a rare exception, having been successfully treated surgically for the condition.
Nearly two years ago, cardiologist Neal Kay, working with the zoo's chief veterinarian, Marie Rush, implanted an advanced pacemaker in Babec's chest. The procedure, called cardiac resynchronization therapy or CRT, corrected the breakdown in the heart's electrical circuitry that comes with fibrosing cardiomyopathy, and restored the organ's ability to contract properly.
On a steamy summer morning earlier this month, the 26-year-old gorilla, whose prognosis is now excellent, looked the picture of health as he pointed to his chest while a visitor looked on.
"Babec is a bright light at the end of an otherwise dark tunnel," said Kay, who treats his human patients at the University of Alabama at Birmingham's Heart and Vascular Center. "We got to him in time."
Medical technology may save the day for individual gorillas, but the answer to why captive gorillas are falling ill remains as tangled as vines in the gorillas' native West African swamps. Veterinarians and medical specialists are also treating ailing gorillas with heart drugs but "have few clues about why gorillas are succumbing to the disease," said cardiologist Ben Byrd of the Vanderbilt University Heart Institute in Nashville, who has advised veterinarians at the National Zoo.
"The thing that has us stumped," said Lowenstine of UC at Davis, "is that it doesn't appear to be related to coronary artery disease or cholesterol levels."
Meehan thinks that "it might be a bacterial or viral infection of the heart. It could be a response to stress, in which harmful substances called catecholamines are released, or something in gorillas' diet in captivity that wild gorillas either eat or don't eat."