has there been a disease with only positive effects?

[mrrealtime]

Is there something that spreads like a virus/disease, that only had positive effects, like makes you stronger, more resiliant, smarter etc?

[Absolute]

Well, there are the bacteria in your gut that help you digest food.

Those would be a disease if they had any negative effects.

[ratatoskK]

One might say that a beneficial genetic mutation is a good disease... (But I think you want examples of infection...)

[pravnik]

If it's beneficial, I don't think you can characterize it as a disease as a matter of definition. A beneficial mutation would be an adaptation, and a beneficial organism would be a symbiote.

[Ranchoth]

I think one of the current theories in biology is that Mitochondria are the decendants of cellular parasites, that have evolved into symbiotes.

[kanicbird]

I think part of the issue is your body's response to a disease is to release stuff that makes you feel like sh!t. So if it were actually something good, it would be a miserable experence getting it.

IIRC part of our cell structure that makes complex life possible (mitocondria?) is thought to be a microbe 'invader', that was somehow enslaved by thehost cell and forced to produce, well basically fuel for the cell.

[pravnik]

Well, on second thought...maybe cowpox could be characterized as a beneficial infectious disease with benefits far outweighing its harm.

[Mangetout]

Originally Posted by kanicbird

I think part of the issue is your body's response to a disease is to release stuff that makes you feel like sh!t. So if it were actually something good, it would be a miserable experence getting it.

AFAIK, it's not so much the stuff that your body releases that directly makes you feel bad, but rather, all the debris comprising dead bits of you (including dead/spent bits of your immune systems), dead bits of the disease pathogens, and toxins created by them. If there were a beneficial infectious agent, your body presumably wouldn't feel the need to fight it and therefore you shouldn't feel lousy from it.

[pravnik]

Okay, on third thought, cowpox was only considered a disease because it seemed to have some injurious effect and the benefits it conferred were not yet known, and the OP asked about diseases with only positive effects...I don't think that's possible by definition.

[Mangetout]

No; you're right a disease with only positive effects is impossible by definition, but there are certainly things that are infectious that are entirely beneficial; gut bacteria (as mentioned by Absolute) being a good example.

[Sattua]

The benefit of having cowpox, by the way, is that it makes you immune to smallpox.

I had to look that up.

[ltfire]

When I was seven, the chicken pox kept me out of school for 2 weeks. That was good.

[panache45]

Originally Posted by ltfire

When I was seven, the chicken pox kept me out of school for 2 weeks. That was good.

Yeah, me too. And scarlet fever was even better: 3 weeks!

[Peter Morris]

possibly mitochondria were originally an infection, now are vital parts of a cell's functions.

[Ranchoth]

Originally Posted by Peter Morris

possibly mitochondria were originally an infection, now are vital parts of a cell's functions.

I'm Mister...cellophane, mister...cellophane, shoulda...been my name, 'Mister Cellophane'...cause you can look right through me, read post five-ey, and...never know I'm theeeere!"

Anyway...I understand that carriers of Sickle-Cell Disease have a higher resistance to Malaria, which is advantagous in certain times and settings. (With the slight, obvious, drawback.)

[Ender_Will]

Originally Posted by Ranchoth

Anyway...I understand that carriers of Sickle-Cell Disease have a higher resistance to Malaria, which is advantagous in certain times and settings. (With the slight, obvious, drawback.)

Blast! This was what I was going to mention. IIRC from HS biology (which is doubtful), if both parents have the sickle cell gene and pass it on to you, your are in a world of hurt. If only one passes it on to you, malaria doesn't phase you, and the negative effects of sickle-cell are minimal.

[KarlGauss]

A similar line of reasoning supposes that the gene for cystic fibrosis (in a single "dose") confers resistance to cholera. Reference.

[davenportavenger]

Not really diseases, more like conditions, but I don't imagine that people suffer too much when they're afflicted with synesthesia or tetrachromacy.

[scr4]

If you include artificial "diseases" - gene therapy basically means creating a virus that fixes whatever's wrong with your body.

[Smeghead]

The mitochondria thing really doesn't fit here. It was pure symbiosis back when it happened, and it probably happened only once. There's no reason to think that the first eukaryotes were going around infecting other unsuspecting prokaryotes with mitochondria.

As for the OP, evolutionary strategy for viruses is for them to have less and less effect on their hosts. We become their home, so it's in their best interest to keep us alive as long as possible. A huge chunk of the human genome is apparently made up of remnants of viruses that got marooned in our DNA.

[psychonaut]

Originally Posted by mrrealtime

Is there something that spreads like a virus/disease, that only had positive effects, like makes you stronger, more resiliant, smarter etc?

Memes.

[susan]

Memes.

Yeah. Education.

[scm1001]

many parasites offer beneficial responses. E.g the current epidemic of asthma, excma, allergies, irritable bowel etc may be due to our clean environment and not enough parasites and bugs. I presume this is due to ouir immune system attacking the bugs and not ourselves. There are several trials of parasite based treatments such as hook worms
e.g. see http://www.asthmahookworm.com/

[The Seventh Deadly Finn]

What about... LOVE? (violins swell)

No, I'm just kidding. Give me a nice, predictable dose of typhoid any day.