ROBERT SIEGEL, HOST:
When the shutdown began 10 days ago, many of the nation's most valuable lab mice were left in limbo. They're held in federal biomedical research facilities where scientists had been trying to find new treatments for diseases, like cancer, diabetes and arthritis. Well, now most of those researchers are banned from their labs. And at the National Institutes of Health, outside Washington, D.C., it appears that thousands of rare and costly research mice will be put to death before the scientists return.
NPR's Jon Hamilton has that story.
JON HAMIILTON, BYLINE: The shutdown poses a special problem for mice that have been genetically altered to develop versions of human diseases, from Alzheimer's to epilepsy. Some of these transgenic mice cost thousands of dollars to replace. Others can't be replaced at any cost. NIH officials aren't doing media interviews. So I asked scientists at Johns Hopkins in Baltimore what a shutdown would mean for their research animals.
Roger Reeves uses hundreds of transgenic mice in his work on Downs Syndrome. And he says to maintain the colony every new pup needs to have its DNA tested by the researchers.
ROGER REEVES: If I thought we were going to be down for two weeks, we certainly would reduce the colony. If I thought it was going to be a month, then I would take a little harder look. And if I thought it was going to be longer than that, then we really would have to take things off the shelf.
HAMIILTON: By freezing embryos and killing entire lines of mice.
Reeves has seen what a government shutdown can do to research. He was at a government lab in the 1980s, when a shutdown forced him to walk away from his experiments with cell cultures.
REEVES: Everything done up 'til that point, lost. It was a complete waste, just an utter waste.
HAMIILTON: Shutdowns in the 1980s lasted no more than a couple of days. The current one promises to go on for weeks. And Carol Greider at Hopkins, a Nobel Prize winner, says that would be disastrous.
CAROL GREIDER: Not being able to breed mice for several weeks could really shut down years worth of experiments.
HAMIILTON: Of course, mice breed even when scientists aren't around. And that presents another problem for the NIH, which ordinarily keeps more than 300,000 mice on hand. Bob Adams, who is in charge of research animals at Hopkins, says that number is probably growing quickly.
BOB ADAMS: Every 21 days a female mouse can have a litter.
HAMIILTON: And how many in a litter?
ADAMS: That varies but it can be a lot, like 10. So you can see it's a geometric progression of how many mice you would have to deal with.
HAMIILTON: Adams says most research institutions don't have much space for extra mice.
ADAMS: We might start moving animals around to facilities where we have some room. But at some point, we would probably have to start euthanizing animals.
HAMIILTON: It's not clear how much of that has already occurred at NIH, where the mouse census had been down a bit because of cuts from sequestration. In an email, an NIH spokesperson said only that institute directors are developing approaches to manage the population.
Adams explains why that will be difficult, as we tour the Hopkins facilities where about 200,000 mice live in stacks of clear plastic cages.
ADAMS: This is what you might call a standard mouse room. It holds about a thousand cages. All the cages receive HEPA filtered air. They receive treated water.
HAMIILTON: Adams says the first thing you do in a shutdown is try to separate males and females. But that requires a lot of extra cages. And pregnant females would still produce new litters, requiring more cages. Adams says within a couple of weeks, they would run out of room. Then, he would have to start bringing animals here, to a stack of air-tight chambers.
ADAMS: We turn the machine on. It slowly brings up the carbon monoxide levels, so they essentially get anesthetized and then they eventually suffocate.
HAMIILTON: Adams says biomedical research often involves killing animals. But usually, he says, there's a better reason.
Jon Hamilton, NPR News.