VOA常速英语:Study: Chimps Used in Medical Research Show Signs of Post-Traumatic Stress

Chimpanzees who've been subjected to invasive laboratory experiments show signs of Post-Traumatic Stress (PTSD) and other psychiatric disorders seen in traumatized humans, according to a new study by animal welfare activists.

About 1,000 chimpanzees currently live in private and government-run laboratory facilities across the United States, where they are used as subjects for medical experiments.

The study findings, published in the non-profit science journal PLoS ONE, focus new attention on a proposed U.S. law to ban the use of chimpanzees in some types of medical research.

Shedding light

The two-year study examined the cases of more than 350 chimpanzees including former lab chimps now living in sanctuaries and those in the wild.

The study's lead author, Dr. Hope Ferdowsian, directs research policy for the Physicians Committee for Responsible Medicine, a private group that promotes alternatives to the use of animals in research, education and training.

Ferdowsian undertook the study primarily for ethical reasons.

“Chimpanzees are taken from their mothers at a very early age, sometimes just after they’re born," she says. "Chimpanzees are also forced into isolation many times as a result of being used in Hepatitis and other protocols. So there are clear harms associated with the use of chimpanzees in research, and we wanted to look at exactly how chimpanzees are affected by all the harms that are inflicted upon them over the course of a lifetime.”

Negra's story

In collecting their data, Ferdowsian and her colleagues relied on feedback from the chimps’ caretakers, who - in many cases - had known the animals for years.

One of the subjects was Negra, who spent 30 years as a test subject in biomedical research before being transferred to a chimp sanctuary.  

Negra's caretakers describe her as socially isolated and withdrawn, and she assumed a depressed, hunched posture, much like you’d see in humans with depression.

“She walked around with a blanket over her head, really isolating herself from the rest of the world,” says Ferdowsian.

Her study concludes that the behavioral changes Negra and many other chimps exhibited after their laboratory experiences were very similar to those seen in combat veterans suffering Post-Traumatic Stress Disorder (PTSD).  

Proposed changes

Ferdowsian supports pending legislation in the U.S. Congress which would phase out experiments on chimpanzees and retire the apes to sanctuaries.

Rep. Roscoe Bartlett,  a Maryland Republican, was a scientist before becoming a congressman and is now the main sponsor of "The Great Ape Protection and Cost Savings Act." He says Ferdowsian’s study confirmed what he already knew.

“That these animals aren’t the usual cow or pig or horse. They really are very different," says Bartlett. "They are primates and they have a huge brain and they have many characteristics similar to humans. It didn’t surprise me, but I was pleased to see the study.”

But some scientists involved in chimp-assisted research challenge the validity of Ferdowsian’s study and the proposed ban.

John VandeBerg, a biomedical researcher and director of the Southwest National Primate Research Center in San Antonio, Texas, finds serious flaws in the study and considers its conclusions invalid.

"The authors appear to have tried to assign a human disorder, Post Traumatic Stress Syndrome, to these chimpanzees and this syndrome is defined primarily by psychological characteristics such as persistent nightmares, recurrent distressing feelings about the event that they have suffered," says VandeBerg. "Chimpanzees aren’t able to relate to us whether they are having nightmares or recurrent, distressing recollections.”

'Devastating blow'

VandeBerg, who uses chimpanzees in the medical research he conducts at his Texas facility, says the animals are treated humanely.

“We have many chimpanzees here at the Southwest National Primate Research Center that have been here for many decades, who’ve been used in experimental research over many decades. They do not exhibit symptoms of depression, and certainly as I say, there is no way of diagnosing Post Traumatic Stress Syndrome.”

VandeBerg says chimpanzee research has led to life-saving medical gains.

“For example, the Hepatitis B vaccine would not have been developed without research with chimpanzees. Hepatitis B vaccine was given to the children in 116 countries of the world. That was a huge medical breakthrough which will save hundreds of millions of human lives.”

Banning the use of chimps in research,  VandeBerg says, will deal a devastating blow to medical research.

But study lead author Ferdowsian insists that there are alternatives for medical research that do not involve using animals, such as computer simulations, cell and tissue cultures, genetic analyses and human population studies.  

And, Ferdowsian says, passage of the Great Ape Protection Act would bring the United States into line with the ethical research standards adopted by other countries.