New York City Mice Carry Bacteria That Can Make People Sick

Apr 17, 2018
Originally published on April 18, 2018 2:43 am

In E.B. White's classic children's story Stuart Little, the eponymous mouse lives happily with a New York City family.

But Dr. Ian Lipkin wanted to know whether cohabiting with a mouse may be hazardous to one's health.

So Lipkin and his colleagues at the Columbia University Mailman School of Public Health spent a year collecting mice from throughout New York City to see whether they carry any dangerous germs.

In two papers published in the journal mBio, the researchers report the results from testing of 416 mice from seven sites.

One analysis found that mice carry a variety of viruses, although none of the viruses are linked to human disease. But the other study found a wide range of bacteria that are known to cause sickness in humans. These included the culprits in sometime serious intestinal infections: E. coli, shigella, salmonella and Clostridium difficile.

"Some of these illnesses are life-threatening," Lipkin says. "These are serious problems."

And some of the bacteria showed signs they could be resistant to treatment by antibiotics.

"You not only have mice carrying bacteria that have the potential to cause human disease, but also carrying bacteria that have components that actually would thwart our ability to treat these infections with antibiotics," Lipkin says.

Lipkin stresses that the researchers haven't actually linked mice to any large outbreaks of human disease. So people shouldn't overreact whenever they see a mouse in the house. But they should take steps to protect themselves.

"I wouldn't think of mice in your house as Stuart Little," says Lipkin, who served as chief scientific consultant on the movie Contagion. "These are serious challenges because they are reservoirs for important human pathogens."

Common-sense steps could minimize the risk. For example, people should block holes that mice might use to get in their homes or apartments. And never eat any food that might possibly have come into contact with mouse droppings — no matter how brief such contact was.

"There is no five-second rule," Lipkin says. "If your food is contaminated with mouse droppings, you shouldn't eat it."

Other researchers who study how animals spread disease agree.

"One doesn't want to say the sky is falling," says James Childs at the Yale School of Public Health. "But nonetheless, these are interesting and important studies."

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AILSA CHANG, HOST:

OK. So no one likes having a mouse in the house, and now new research suggests the rodents may pose a greater risk to human health than previously believed. NPR health correspondent Rob Stein has the details

ROB STEIN, BYLINE: In the 1999 movie based on E.B. White's classic children's story, "Stuart Little," a New York family adopts an adorable mouse.

(SOUNDBITE OF FILM, "STUART LITTLE")

HUGH LAURIE: (As Mr. Little) Attention, everybody.

GEENA DAVIS: (As Mrs. Little) This is Stuart.

MICHAEL J FOX: (As Stuart Little) Hello, everyone.

JONATHAN LIPNICKI: (As George Little) Are you all nuts? He's a mouse.

STEIN: Ian Lipkin at Columbia University wanted to know whether Stuart Little's human brother had it right. Were they nuts? Are mice trouble, even maybe more than rats?

IAN LIPKIN: Because they actually live inside our houses or our apartment buildings - a far more intimate relationship between mice and humans than rats and humans.

STEIN: So Lipkin and his colleagues spent a year collecting mice from all around New York City, so they could test them to see whether they carry any dangerous germs.

LIPKIN: We found a wide range of very important bacteria that are known to cause disease in humans - bacteria that have been implicated in outbreaks of disease.

STEIN: Like salmonella, E. coli, something called clostridium difficile.

LIPKIN: Some of these illnesses are life threatening. I mean, people die of clostridium difficile. People die of klebsiella. People die of all of these. So these are serious problems.

STEIN: And many of the germs appear to be resistant to treatment by antibiotics.

LIPKIN: So you not only have mice carrying bacteria that have the potential to cause human disease but also carrying bacteria that have components that actually would thwart our ability to treat these infections with antibiotics. So it's a very important finding.

STEIN: Other researchers agree but caution that just because the mice are carrying germs doesn't necessarily mean they're spreading them to people. James Childs is at the Yale School of Public Health.

JAMES CHILDS: One doesn't want to say the sky is falling. But nonetheless, these are interesting, important studies.

STEIN: Lipkin agrees there's no need to panic next time you see a mouse in your house, but don't assume they're necessarily harmless either.

LIPKIN: You know, I wouldn't think of mice in your house as Stuart Little. These are serious challenges because they're reservoirs for important human pathogens.

STEIN: So people should take common-sense steps to minimize the risk, like block up holes that mice might use to get into your house or apartment. And definitely don't eat any food that might have come into contact with mouse droppings.

LIPKIN: Now, I'm not suggesting that people should use toxic pesticides to get rid of them. But there are ways in which you can eliminate mice or at least control them to make certain that your exposure is minimized.

STEIN: He puts it this way.

LIPKIN: There is no five-second rule. You know, if your food is contaminated with mouse droppings, you shouldn't eat it.

STEIN: Rob Stein, NPR News. Transcript provided by NPR, Copyright NPR.