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Scientists are questioning the benefits of chimp research, just as the United States is planning to restart such work after a 10-year moratorium. And while the usefulness of performing experiments on chimpanzees is debated, some things are clear: The animals often suffer mental distress over the treatment and often have shortened life spans. McClatchy Newspapers correspondent Chris Adams reports.
Donovan the chimp transformed from a friendly ape who "adapts well to peers" to one who beat his female cage-mate so aggressively they had to be separated.
Lira became a "chronic hair-plucker", with large barren patches on her body.
Bobby bit and mutilated his own arm, leaving permanent scars. He was so depressed that he slept sitting up, facing the wall of his cage.
The debate about medical testing on chimpanzees often revolves around the physical impact on the chimps - week after week of liver biopsies or year after year of being infected with HIV or hepatitis.
But an examination by McClatchy Newspapers of the chimp-research world found that, in addition to a physical toll, the testing life can have a significant impact on a chimp's mental state.
The science of chimp research is dicey. The United States is virtually alone in the world in pursuing it, and many scientists say the chimps' value as a medical model is declining. Chimps are among humans' closest genetic cousins, and given their range of emotions and their level of understanding, researchers themselves afford chimps special protections that other research animals don't get, even monkeys.
According to the National Research Council, the public "expects a high level of respect for the animals", given the "special connection of chimpanzees to humans".
For the chimps, research can be lonely and debilitating; some end up with mental ailments including post-traumatic stress disorder or depression. Sometimes the symptoms will ease once the testing ends, but sometimes they stick with a chimp for life.
"Chimpanzees depend on close physical contact. They love their comforts, and like to stretch out on a nice soft bed of grass. They make their own choices all the time," chimp researcher Jane Goodall said.
The researchers who handle the chimps disagree. They say the chimps are treated well and humanely, oversight panels ensure that only necessary research is performed on them, and they're given space to move and play.
John VandeBerg, who oversees the primate facility at the Texas Biomedical Research Institute, said the chimps were treated compassionately and that life in the lab was good.
The chimps, he said, even have televisions. They like to watch animal movies.
The effort to understand the chimps' minds has grown in the past decade.
One chimp who helped illustrate the impact of research was Billy; his story was chronicled in the medical journal Developmental Psychology in 2009.
Raised as an entertainer - working the birthday party circuit - Billy lived compatibly with humans and had a strong bond with his owners before he was given over to researchers at age 15.
At a chimp lab in New York, he was caged alone, except when paired with Sue Ellen for breeding; he attacked her instead. For 14 years, he was used for research into hepatitis, HIV, measles and polio. During that time, he turned hostile, unco-operative, aggressive and depressive; he wouldn't interact normally with other chimps. After one experimental procedure, he chewed his thumb off.
Even when he left the lab for retirement at a sanctuary, Billy remained fearful and agitated. He screamed if the door to his cage was left open, and he couldn't go to sleep until he himself had tested that the door was locked.
Billy had an impressive memory and he interacted well with humans, even mimicking them at times, by spooning cream and sugar into his coffee, for example.
One day, Billy became excited while he was watching television. He gestured wildly for the facility director to come look. On the TV screen: Goodall. Billy had met her years before. The director turned up the TV volume, and Billy sat to watch the programme.
Many of the animals in New Mexico saw the same kinds of changes in their personalities that Billy did.
Their stories emerge from thousands of pages of medical records that an advocacy group, In Defence of Animals, unearthed after a lengthy legal fight with the NIH. The records were provided exclusively to McClatchy with no strings attached, for its own review.
Donovan was born in 1995, and today he's described as having a light-coloured mouth and eyebrows. His fact sheet says he "likes people, gets along with group, playful".
His favourite food is "anything". One of the earliest entries in his medical file was in July 1996, when he was first paired with a female named Sakari as they were being prepared for shipment from Alamogordo to a separate research facility. "Animals seem to be getting along well at present," according to his file.
But there was one red flag: "Adapts well to peers. Does not adapt well to handlers." Donovan's research record from early 1997 to early 2001 shows week after week of bleeds and biopsies. While some chimps can be trained to present their arms for injections, Donovan's chart says he doesn't do that. That usually means chimps are required to go through what's known as a knockdown, shooting them with tranquilizer darts so they can be moved to exam rooms. There, lab workers can draw blood, saliva or other fluids.
It's not often a smooth process.
"You have a sentient animal, with similar emotions and intelligence to us," said Laura Bonar, an advocate with a New Mexico animal rights group that's tracked the Alamogordo chimpanzees.
"They are housed by themselves, where they can't have companionship from other animals, although probably they can hear. So when I've seen footage of knockdowns, there's a lot of anxiety, a lot of screaming from the other chimps."
What the chimpanzees often see is workers coming towards them in biohazard suits. They get shot, and if they're on perches, they fall to the concrete below.
The records don't reveal specifically how Donovan handled the blood draws.
But his temperament changed. In November 1997, his chart and Sakari's said the two had needed to be pulled apart.
Sakari's chart said: "Separated from 1588 [Donovan] because he has become very abusive towards her - biting fingers [plus] beating on her back [plus] chest."
He suffered in other ways as well. In April 1998, Donovan underwent a procedure that was part of a hepatitis C experiment. Within five minutes, his heart rate plummeted to 60 beats per minute, from its normal 90 or 100. His heartbeat was very irregular, his breathing laboured. He turned pale. It took about an hour for the episode to pass. Another time, during a liver biopsy, the needle hit his gallbladder.
From before his second birthday until he was 6 years old, researchers subjected Donovan to 200 bleeds and 40 biopsies. He spent much of his time housed alone, and in 2002, a memo from the US Department of Agriculture, which has some oversight over animal laboratories, noted the impact of such housing on Donovan and 13 other chimps: "Because of the long-term housing in these single cages, these chimpanzees have not been able to perform species-specific behaviours, including social and physical behaviours ... normal exercise and full stretching are not possible in these cages. This has ... caused physical and psychological suffering and distress to the chimpanzees."
Donovan was removed from research and transferred to the Alamogordo Primate Facility that year.
Other chimps reacted in other ways.
Lira, a 17-year-old female who recently died, took part in late-1990s hepatitis research. She was cut open, her liver exposed and then directly injected with hepatitis. Eight months later, she was infected again, this time with five needles directly into her liver or spine. More than a year after that, she was infected with hepatitis yet again and underwent liver biopsies every other week for several months to track the disease's progress. The details of those experiments - which included a tracking number, allowing the identification of the chimp in question as Lira - were published in scientific journals in 2000 and 2002.
But it wasn't until her medical records were released that it became apparent what else was going on at the time of the experiments.
For more than two years, starting when she was 4 years old, Lira was housed alone, given the requirements of the study she was part of. During that time, she had "liver and muscle damage from multiple percutaneous liver biopsies". In 2000, her records said she was a "chronic hair-plucker" and had large bald areas on her body. In 2001, the records noted she "appears depressed" and said to "continue extra enrichment".
Lira was one of the most recent chimps to die at Alamogordo. Last May, an NIH record said, she experienced "sudden cardiac death" at age 17. That was very young, given that female chimps can easily live into their 30s or 40s. Lira's body was weak, and had signs of multiple bite wounds. Her "liver was enlarged" and her spleen "enlarged and friable". Her brainstem "appeared enlarged and swollen with areas of liquefaction".
The NIH won't detail all the kinds of tests that Donovan and the other still-living chimps could undergo if they go back into research. The NIH said chimps were essential for research and that it would "ensure humane and fair treatment of these animals".
"I think everybody recognises that if we had an alternative model we would be using it," said Sally Rockey, a deputy director at the NIH who oversees animal testing.
"Since it is the only model we have now, it's crucial that we continue."
Many scientists disagree, saying the knowledge once gained only by examining a live animal now can be learned in a petri dish, and that chimpanzees don't work as human fill-ins, as once had been hoped.