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Last Updated

02 Jan 2003

Source: Wall Street Journal, May 14, 2002.


Monkey Deficit Crimps Laboratories As Scientists Scramble for Alternatives


Scientists have infected rhesus monkeys with polio, coaxed them into cocaine addiction, shot them into space and cloned them. Researchers like working with them for a simple reason: their great similarity to people.

Now, though, rhesus monkeys have become so scarce and expensive that scientists are forced to look for alternatives. That's a sharp turnaround from decades ago, when the animals were imported from India by the thousands for as little as $80 apiece. Drug companies came to depend on them to test new products, and their low cost and easy access made them the standard for research that ethically couldn't be done in humans.

These days, rhesus monkeys often cost more than $5,000 each, with a healthy female commanding anywhere from $6,000 to $14,000 per animal. And even researchers who can afford them spend months waiting, as monkey brokers and breeding centers scramble to locate enough animals.

When University of Pittsburgh virologist Michael Murphey-Corb tried to buy 32 rhesus monkeys for an experiment last year, they were so expensive -- as much as $6,000 each -- she had to scale back her research into an AIDS vaccine.  Forced to settle for 24 animals, Dr. Murphey-Corb had to defer investigating whether the vaccine would work as an early treatment for the disease. Fed up with spending a third of her time trying to find rhesus monkeys, Dr. Murphey-Corb says she is switching to a closely related species, the cynomolgus monkey, which costs about half as much as the rhesus and is readily available. "I have to get on with my research," she says.

The FDA doesn't have rules requiring rhesus monkeys to be used for research, but because the rhesus was typically used in past experiments, corporate researchers are reluctant to conduct studies for product approval if their results might be questioned on the basis of what type of animal is used.

In the 1970s, researchers bought as many as 12,000 rhesus monkeys annually from India, the main source for the animals, also known as rhesus macaques or Macaca mulata. The export of the monkeys was already controversial and sensitive in India, as Hindus consider them a sacred incarnation of a god. Then, in 1978, India banned the exports after news reports that the U.S. was using them in radiological weapons experiments. The price per monkey jumped from about $100 to about $4,000.

"It was just like OPEC cutting off the oil supply," says David Robinson of Battelle Memorial Institute, a nonprofit research and development corporation with headquarters in Columbus, Ohio.

The species became even more coveted in the 1990s, when it became the primate model in AIDS studies. The animals develop a disease much like the human version when infected with HIV. The recent focus on bioterrorism research has further strained the supply.

Before last fall's anthrax outbreak, testing of an anthrax vaccine stalled for two years because federal researchers couldn't get enough rhesus monkeys. Out of urgency, they decided to use Chinese instead of Indian rhesus. But making that switch presents its own problems. Anthrax research done in the 1950s relied on Indian rhesus, and scientists have disagreed about whether the Chinese animals are similar enough to use in new studies.

Programs aimed at breeding more rhesus monkeys for medical research haven't eased the shortage, although eight federally funded primate centers are working to increase the domestic supply. In fiscal year 2000, 57,218 primates were used in research, according to the Department of Agriculture, but no one keeps a comprehensive count of how many rhesus monkeys are actually needed.

At Tulane University, outside New Orleans, about 3,000 rhesus macaques ramble inside 22 half-acre outdoor corrals. Tulane struggles to balance the number of monkeys it keeps for breeding with the number it makes available for research.

Getting rhesus monkeys to reproduce isn't like breeding rabbits. "You can't speed up the production line for an anthrax scare or anything else," says Andrew Lackner, director of the Tulane center. Females give birth once a year, after about five months' gestation. Healthy females usually mate successfully with one of the males in their breeding corral, says Richard Harrison, a Tulane reproductive biologist. But not all males are fertile, and some females resist mating, he says.

A scientific committee at the Pharmaceutical Research and Manufacturers Association, a drug-industry trade group, is discussing what studies are necessary to persuade the Food and Drug Administration that experiments with other primates and even other animals, such as rats, might be applicable to humans. Michael Friedman, PhRMA's chief medical officer for biomedical preparedness and senior vice president at Pharmacia Corp., hopes that the shift of bioterrorism research away from rhesus monkeys whenever possible will help ease the supply crunch for other fields.

Officials at the National Institutes of Health hope a National Academies of Science workshop held in April will prompt researchers to use primates other than the Indian rhesus macaque.

But those who oppose animal experimentation say researchers, in focusing on accumulating enough rhesus macaques for their work, are ignoring the possibility of moving away entirely from such research.