# So why aren't there any beneficial infectious bacteria/viruses? **URL:** \ **Category:** Factual Questions\ **Created:** [March 26, 2009, 6:39pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894 "2009-03-26T18:39:27Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [March 27, 2009, 3:40am UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/21 "2009-03-27T03:40:36Z")
Then there are the countless viruses, or viral fragments, which have made their way into our DNA . They are presumably on the whole positive or they would have been selected against. My question to the OP is: how do you know we don’t already have beneficial infections? ---
**Author:** ![Markxxx](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@Markxxx](https://boards.straightdope.com/u/Markxxx)\ **Post date:** [March 27, 2009, 3:54am UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/22 "2009-03-27T03:54:41Z")
Don’t forget a lot of bacteria that do no harm but don’t help really CAN help us in a way. Bacteria are living and they need food and room to move. Supposing you have a bunch of bacteria in your stomach that do no harm but do no good for you either. Now suppose a bunch of evil bacteria find their way into your stomach. Now if since it’s full of benign bacteria (those germs that do no good or evil), these newly introduced “evil bacteria” have to compete with them. But suppose there’s no food in your stomach for the “evil bacteria” because the benign bacteria have already eaten it up. Well these evil bacteria die. Supposing there’s no room for the “evil bacteria” to move, because the benign ones are taking up all the space. The "evil guys’ then die. If it wasn’t for that benign bacteria there would be nothing to stop the bad germs from getting a hold, before the immune system could respond. This way, sometimes even germs that don’t hurt you or help you can have uses too ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [March 27, 2009, 4:27am UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/23 "2009-03-27T04:27:22Z")
> [@Askance](#): > > Then there are the countless viruses, or viral fragments, which have made their way into our DNA . **They are presumably on the whole positive** or they would have been selected against. Or at least not evolutionarily harmful :smack: ---
**Author:** ![hotflungwok](https://avatars.discourse-cdn.com/v4/letter/h/edb3f5/32.png) [@hotflungwok](https://boards.straightdope.com/u/hotflungwok)\ **Post date:** [March 27, 2009, 2:18pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/24 "2009-03-27T14:18:10Z")
> [@Askance](#): > > My question to the OP is: how do you know we don’t already have beneficial infections? The same way we find out that cold is caused by a virus and not evil influences. If every time someone gets a certain flu strain, they smell like pine trees, then we can investigate whether the flu causes the smell. Do we have any periodic beneficial effects that we have a need to explain? ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [March 27, 2009, 2:30pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/25 "2009-03-27T14:30:36Z")
> [@Askance](#): > > Then there are the countless viruses, or viral fragments, which have made their way into our DNA . They are presumably on the whole positive or they would have been selected against. [Endogenous retroviruses](http://en.wikipedia.org/wiki/Endogenous_retrovirus) may have a role in protecting the foetus from the maternal immune system. However, many EVRs have been deactivated by transcription errors and the like, and serve no practical purpose (except to supply additional DNA material into the genome that may be repurposed by mutation and selection over time). Si ---
**Author:** ![HorseloverFat](https://avatars.discourse-cdn.com/v4/letter/h/8e8cbc/32.png) [@HorseloverFat](https://boards.straightdope.com/u/HorseloverFat)\ **Post date:** [March 27, 2009, 3:24pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/26 "2009-03-27T15:24:50Z")
\>Do we have any periodic beneficial effects that we have a need to explain? Supposedly, there’s an immune system connection and general health. So getting a cold periodically may lead to not getting asthma or some other disease later in life because of a stronger immune system. So, its not exactly pine smell, but there may be non-obvious benefits to even the common cold and perhaps this is why our immune system never evolved to defeat a lot of these cold viruses: we simply were benefiting more from getting sick every so often. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [March 27, 2009, 5:12pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/27 "2009-03-27T17:12:06Z")
> [@hotflungwok](#): > > Do we have any periodic beneficial effects that we have a need to explain? That’s a somewhat more interesting question than it may appear. We’re highly motivated to research diseases and other things that make us feel bad. No one ever goes to the doctor to report that they’re feeling good for no reason, as Lister points out in the Red Dwarf episode. Certainly, no one’s researched feeling good nearly as much as feeling bad. I still don’t think it’s likely for reasons I explained before, but it’s always fun to speculate. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [March 27, 2009, 7:16pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/28 "2009-03-27T19:16:30Z")
> [@Yllaria](#): > > Bolding mine. > > If you have any cites handy, I’d love to learn more about that. > **[Press Releases](https://www.niams.nih.gov/newsroom/press-releases)** > > Press Releases are news about major scientific findings on issues related to the NIAMS. These findings may be the result of work done by our NIAMS staff or our grantees. Press releases may also describe recently funded grants. Understand that the role of bacteria in many functions is just being discovered. Some arthritis is being linked with gut bacteria getting off balance, which could suggest that there were other bacteria keeping them at bay. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [March 30, 2009, 4:19am UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/29 "2009-03-30T04:19:49Z")
> [@hotflungwok](#): > > The same way we find out that cold is caused by a virus and not evil influences. If every time someone gets a certain flu strain, they smell like pine trees, then we can investigate whether the flu causes the smell. Do we have any periodic beneficial effects that we have a need to explain? Lots. I feel particularly good every now and then for no obvious reason. Beneficial virus? No idea. Not interested in investigating whether it is either. But it could be, if it impelled me to contact more strangers and so pass is on. ---
**Author:** ![Anaglyph](https://avatars.discourse-cdn.com/v4/letter/a/ed8c4c/32.png) [@Anaglyph](https://boards.straightdope.com/u/Anaglyph)\ **Post date:** [March 30, 2009, 2:59pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/30 "2009-03-30T14:59:35Z")
vaccinia virus (cow pox) infection is a relativly harmless infection that used to protect against smallpox. Therefore, before the eradication of smallpox, you could have called a vaccinia virus infection beneficial. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [March 30, 2009, 3:39pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/31 "2009-03-30T15:39:41Z")
Possibly, but you’d have to balance the benefit of smallpox immunity against the small percentage of people who got deathly ill or even died from the vaccinia virus itself. ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [March 30, 2009, 3:41pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/32 "2009-03-30T15:41:18Z")
> [@clairobscur](#): > > That has to be one of the weirdest link I read on this board. Brazilians are more sexual than Britons because a fucking parasite wants to make its way to a cat??? :eek: > > What will we learn next? That the real cause of WWII was a virus attempting to infect a rhododendron? > > It isn’t April’s fools day, is it? I knew it, cats \*\*are \*\*plotting to take over. 🙂 ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [March 30, 2009, 3:59pm UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/33 "2009-03-30T15:59:59Z")
> [@HorseloverFat](#): > > T.gondii affects human behavior. It makes women more outgoing and potentially more sexual. Short article here: > > [Brain parasite drives human culture | Not Exactly Rocket Science](http://notexactlyrocketscience.wordpress.com/2007/01/14/brain-parasite-drives-human-culture/) > > Someone wrote a paper that argues that [toxoplasmosis helped bring about human cultural diversity.](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T2J-4F65K94-5&_coverDate=03%2F31%2F2005&_alid=355699223&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=4920&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=9859f86a767bc7be68e741c34801e6b2) _blink_ WT_F?!!_ I remember reading about some parasite that infected a caterpillar and made it go up to the top of the grass stem and wait, so that it could get eaten by its next host, but this…? ---
**Author:** ![Anaglyph](https://avatars.discourse-cdn.com/v4/letter/a/ed8c4c/32.png) [@Anaglyph](https://boards.straightdope.com/u/Anaglyph)\ **Post date:** [March 31, 2009, 7:03am UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/34 "2009-03-31T07:03:54Z")
> [@Smeghead](#): > > Possibly, but you’d have to balance the benefit of smallpox immunity against the small percentage of people who got deathly ill or even died from the vaccinia virus itself. In Jenner’s time, smallpox was indeed a major cause of dead, and vaccination a major progress ([pdf](http://web.clark.edu/tkibota/240/Disease/Smallpox.pdf)) ---
**Author:** ![The\_Second\_Stone](https://avatars.discourse-cdn.com/v4/letter/t/bbe5ce/32.png) [@The\_Second\_Stone](https://boards.straightdope.com/u/The_Second_Stone)\ **Post date:** [March 31, 2009, 7:30am UTC](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894/35 "2009-03-31T07:30:18Z")
You might possibly be interested in the subject of bacteriophages. [Bacteriophage - Wikipedia](http://en.wikipedia.org/wiki/Bacteriophage) [Previous page](https://boards.straightdope.com/t/so-why-arent-there-any-beneficial-infectious-bacteria-viruses/490894.md?page=1)