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No one enjoys being sick, especially when it involves re-living what you or your kid had for dinner last night.   But so-called stomach bugs or “stomach flus” are more than uncomfortable—they kill hundreds  of thousands of people every year, including many children. And right now, there's not a whole lot we can do once these viruses take hold.  We don't have antivirals for them, like we have for HIV or the actual flu.  Doctors can provide supportive care, like lots of fluids, but nothing to slow or stop the actual infection.

Or, I should say, nothing yet.  A new study published last week in Science Immunology has renewed the hope that, one day, these diseases will be treatable. The research highlights an exciting new medicine that weaponizes our own immune system to combat these nasty viruses! And it may end up helping treat all sorts of awful viral infections.

Stomach bugs—or, more technically, the viruses that cause viral gastroenteritis—aren't just an inconvenience. While these infections aren't considered deadly, the dehydration they can cause is.  And symptoms like nausea, vomiting, and diarrhea tend to be more severe in children under 5.  That's why the World Health Organization and other healthcare professionals are eager to find ways to treat infections from rotaviruses and noroviruses— the chief viruses which cause gastroenteritis.  Both are notorious for their ability to survive outside of people for a long time and spread really rapidly once they find a group of potential hosts. And they're unfortunately super common: almost every child in the world will have contracted rotavirus at least once before their 5th birthday, and noroviruses infect hundreds of millions of people every year.

Now, there are rotavirus vaccines, but none for noroviruses—not for a lack of trying. And while vaccines are great, they can be hard to get in some areas, and they aren't 100% effective, either.  Plus they only work if your body can launch a proper immune response, which is not the case for people who are immunocompromised.  So what doctors would really like is a way to fight these infections when they inevitably do happen. And they think they've got a pretty neat way to do that: by boosting the body's own attack!  You see, both rotaviruses and noroviruses make themselves at home in the very cells meant to protect us from them: epithelial cells.

You can find these cells all over our bodies—everywhere that's exposed to the outside world in some way.

So: your skin, the lining of your throat, and your entire digestive system, which yes, even though your intestines are inside you, the inner lining of them is exposed to food and other things you bring in from the outside world via your mouth.   These intestinal epithelial cells also perform the essential task of balancing the movement of water and nutrients

to keep your digestive system running smoothly.  So when they're infected, the small intestine stops absorbing what it should, grinding the actual digestion process to a halt. That ultimately means a bunch of undigested material makes it to the colon. And all that stuff that shouldn't be there draws water out of the body, leading to diarrhea and the potential for severe dehydration.     But it's not like the body just is sitting there while all this is happening.  When someone gets infected with a rotavirus or a norovirus, their immune system starts producing molecules called cytokines, which sound the alarm that viral particles have been detected and launch the defensive assault. Like, some cytokines cause changes within epithelial cells that keep the virus from being able to attach or replicate in them.

The new research attempts to harness some of the useful powers of cytokines. And early results are promising — at least in mice.  The team found that a pair of cytokines named IL-18 and IL-22 worked together to knock out stomach bugs. IL-18 tells infected epithelial cells to die off, whereas IL-22 tells all epithelial cells to replicate faster, increasing their turnover at the infection site.  And because of both of those actions, the duo was able to rapidly eliminate rotaviruses and noroviruses from the animals.  This study may be the first step towards developing a targeted treatment that could quickly and efficiently rid anyone of the quote “stomach flu”.

Not only did work well, it could theoretically be administered to people with compromised immune systems, since it doesn't rely on a fully-functioning immune system to work. And it is not just a potential stomach bug cure. It could be used against any virus that targets short-lived epithelial cells including the coronavirus responsible for the COVID-19 pandemic!

Of course, we're going to need more research to know whether this treatment will work in people and also be safe in people who are, ya know, not mice.  But even if this particular cocktail doesn't make it to market, this strategy of weaponizing our immune systems to stamp out viruses will likely be a big part of the future of medicine.  Thanks for watching this episode of SciShow news! If you like learning about what's happening in the world of science, be sure to click on the subscribe button and ring the notification bell. And I would also like to give a special thank you to all of you amazing people who support us—whether it's here on YouTube as a channel member, or as one of our legion of Patreon patrons, or in some other way.  We love being able to share incredible discoveries and all other sorts of weird, wonderful science with you.

So, thank you for helping us do that!  [♪ OUTRO].