Germ-Free Mice, Coywolves, and One Less Ebola Outbreak

Today I Learned:
1) More about germ-free mice! For those not in the know, germ-free mice are mice, well, without germs. They're raised from birth in sterile environments, so they have no bacteria, archaea, or protists in them (some have intestinal worms, interestingly, which must have been transmitted in the womb!).

Germ-free mice were first made in the 1950s to test whether such animals could live. The hypothesis at the time was that they wouldn't; it was thought that bacterial symbionts, particularly in the gut, would be critical for survival. That turns out not to be the case.

I find it interesting that in the last decade, there's been a ton of research suggesting that gut biota are more important than we ever thought... except it's not more important than we ever thought, because we used to think gut biota were indespensible!

How do you make a germ-free mouse? Luckily, I learned this today too! The womb turns out to already be sterile, which is convenient. Then you birth the mouse by C-section in a sterile environment, to avoid bacterial contamination durin birth. Then you wean the mouse using a germ-free surrogate mother. If you don't have a germ-free surrogate mother available, you just... don't wean the pup. You just feed it by hand, I guess (again, sterilly).

Germ-free mice live just fine, although they have some dietary problems. For one thing, they suffer chronic diarrhea, so they drink a lot. They're also not the best at digesting proteins. Coming up with food they can eat is also pretty tricky. Most food, after all, has bacteria in it, which would contaminate the mice. Worse, since they have no experience with bacteria, they have pretty strong immune reactions even to bacteria that would normally be harmless, so you can't just autoclave the food (the bacterial antigens would still be present). From what I gather, germ-free mice are fed a diet not dissimilar from bacterial broth.

Thanks to Chigozie for digging up a ton of info on germ-free mice!

2) There's a species of canine called a coywolf that's a recent natural cross-breed between wolves, coyotes, and domestic dogs. They arose sometime in the last century, and have been shockingly successful, especially at hunting deer.

3) As of today, or sometime very recently, Sierre Leone is officially Ebola-free. Go modern medicine!