In more rodent news...

...it seems that medical scientists may have been keeping lab mice a bit too clean for their (the scientists) own good:

What Pierson is doing breaks the rules. For more than 50 years, scientists have worked to make lab mice cleaner. In most labs today, the animals’ cages are sanitized, and their water bottles and food are sterilized. “We really go to great lengths to keep natural infectious experience out of the mouse house,” says David Masopust, an immunologist at the University of Minnesota who heads the lab where Pierson works. Those efforts have paid off: with the confounding effects of pathogens controlled, mouse experiments have become less variable.

But a raft of studies now suggests that this cleanliness has come at a cost, leaving the rodents with stunted immune systems. In a quest for standardized and spotless mice, scientists have made the creatures a less-faithful model for human immune systems, which develop in a world teeming with microbes. And that could have serious implications for researchers working to usher treatments and vaccines out of the lab and into the clinic. Although it’s not yet possible to pin specific failures on the impeccable hygiene of standard mouse models, Masopust thinks the artificial environment must have some effect. It’s no secret that the success rate for moving therapies from animal to humans is abysmal — according to one estimate¹, 90% of drugs that enter clinical trials fail. “You have to wonder if you might sometimes get misinformed simply because you’re in a clean environment,” says Masopust.

Read the whole thing, at Nature.