It’s a tricky situation. Like humans, apes have blood types and can react disastrously to mismatched donor blood, but unlike humans, great apes aren’t routinely blood-typed, so finding a suitable donor is very difficult.
Until recently, zoo veterinarians approached transfusion medicine with good guesswork and crossed fingers, waiting until they had both the donor and recipient animals under general anesthesia to test whether they were a blood match.
But new research from the Lincoln Park Zoo might change the way clinicians approach ape transfusions.
Dr. Kathryn Gamble, director of veterinary services and Jill Moyse, assistant lead keeper, spearheaded a global effort to type the blood of great apes – chimpanzees, gorillas, bonobos and orangutans – in zoos and in situ facilities, where animals are managed in their country of origin.
Their research, published online in Zoo Biology in September, typed collected blood samples and assigned human ABO blood groups to more than 680 great apes.
"Our initial foray was very clinical," Gamble said. "We had transfusion questions and we wanted to know how to answer them."
Despite past medical research and scientific interest in human-ape similarities, Gamble said little exhaustive information exists about blood types in great apes. There has also been buzz, including an October "60 Minutes" episode, about the possibility of blood transfusions between humans and great apes.
Gamble said ape blood, although it can be typed and genotyped similarly to human A, B, AB and O blood groups, is neither identical to nor interchangeable with human blood. In particular, protein molecules on the surface of red blood cells, called antigens, are different in humans and apes and can be recognized by the immune system as being foreign or what scientists call non-self.
"You're looking at the pattern of the proteins that are coded by the chromosome," Gamble said. Non-self antigens can trigger the immune system to respond, potentially causing a range of complications, from hives to full anaphylaxis -- a severe, full-body allergic reaction that can lead to death.
Gamble said the lack of information about great ape blood was problematic.
"In both medicine and veterinary medicine, it’s very clear that transfusions are important, and good transfusion medicine is critical, yet here we are with all these fabulous animals and we don’t even know where to start."
One roadblock is that great ape blood collection generally requires the animal to be under anesthesia, which an invasive procedure generally conducted every couple of yearsfor a full physical. Few researchers are willing to sedate their zoo animals simply for a blood draw.
The beauty of this study, according to Lincoln Park Zoo Primate Curator Maureen Leahy, is that Moyse and Gamble thought ahead, collecting blood samples from animals that were sedated during routine physical exams.
"Getting access to blood has historically been the challenge," Leahy said, "but by working with zoos, sanctuaries and populations from the wild, we’re getting really phenomenal information in an opportunistic way."
Moyse said participating facilities, from the U.S. and Canada to Borneo and Africa, collected blood during scheduled exams over the last five years. Blood-typing cards were photographed or mailed back to the Lincoln Park Zoo, which now maintains the first ape informational “blood bank” in a huge red binder.
The zoo included data from their 21 apes – 11 gorillas and 10 chimps.
Moyse is taking collection a step further with Kwan, a 21-year-old silverback gorilla. Through a training process called operant conditioning, he is working toward giving blood "voluntarily" – while awake. As a young, healthy male, Kwan is a potential blood donor for other gorillas in need.
Dr. Pam Dennis, veterinary epidemiologist at the Cleveland Metroparks Zoo, called the study cutting-edge.
"Anytime we need to do a transfusion, it’s when something is about to die and we need to save it," Dennis said. It’s an urgent process plagued by inefficiencies in figuring out which animals would be good donors.
"This study helps answer those questions ahead of time," she said, "which would be very valuable."
This research also could be applied to great ape species management. All great apes are part of the Species Survival Plan, a program developed by the Association of Zoos and Aquariums to manage and conserve select or endangered species.
Dennis pointed to using blood groups to inform breeding programs at zoos and in situ facilities, because species survival plans rely on maintaining genetic diversity in finite populations.
Another application, Gamble said, is avoiding maternal-fetal incompatibility in breeding attempts.
"Suddenly you have different reasons that blood types become important, so for great apes, because they’re very similar to humans, they have a special kind of placenta that allows the antibodies to potentially pass across during pregnancy."
If a mom is the wrong blood type and has antibodies to her infant’s blood antigens, immune reactions could result in a weak or stillborn infant.
Gamble, who has already received two calls from colleagues facing potential transfusion situations, said this research serves as an important jumping off point for further knowledge.
"It’s not, 'Oh my God, we have this -- now we can go and conquer the world,'" Gamble said. "But it’s still a very important tool that we now have."
This story originally appeared in Medill Reports, from Northwestern University.