Fever: Is it a natural way of getting used to things?

I like to understand our bodies in the context in which they're designed to work. That's in an ecosystem where they're constantly figuring out how to thrive in an environment that's forever changing.

We can all see the big changes but I'm really talking about the tiny ones like new viruses and bacteria spreading around. The 20th century brought cleanliness on a mass scale so our bodies didn't have to get used to protecting themselves so much against microbial and viral invaders. That's the theory and we all got used to being healthy pretty much all the time. Yet it's also possible to argue that our bodies have got lazy because they are trained to fight off these invaders. I'm wondering whether it's this very cleanliness that means our bodies fail to build up the natural resources that others in less developed parts may have. 

On the other hand I'm also wondering that the ease of travel throughout the globe that we now enjoy means that any one of us is exposed on a very regular basis to any number of foreign invaders. Take the current swine flu epidemic. Working at the OU I sit across from someone who just came back from Mexico during the outbreak. True they were 500 or so miles from where it occurred but I could easily see that someone fromt he infected area could have travelled through the area my colleague was in or even been in the same airport. 

Taking this further most if not all of us are only a few degrees of separation away from someone who has been in a foreign land and could pick up foreign bugs. These foreign bugs could therefore easily trainsfer to our native lands and spread very quickly. 

I've been noticing for a while now how much I feel feverish but don't actually get sick. I take the fever as a sign that my body is adjusting to something or repelling a foreign invader (virus or bacteria or something). So I ease up on my body to spare its resources and help it in its fight. That seems to work well and it's been making me wonder if this fever response is something that's important for us to work with on a regular basis. Maybe it's our bodies way of adapting to changes at a microbial level that we can't even perceive. 

So what am I getting at? I'm not setting out to prove anything. I just like to talk things out and see where they lead. But what I do take from all this is that the western illnesses we all hear about could in part be affected by the western ability for travel which encourages quickly spread of disease. Diseases which we haven't had time to adapt to and we don't have siblings and friends that may have developed a resistance which we may be able to adopt ourselves. 

Ok that last bit sounds far fetched but I've implied before that if bacteria or viruses can make us ill then they can also make us better and resist illness. It's easy to argue that the inhabitants of a village where a disease is common may develop immunity to the disease even if that's simply by harbouring viruses or bacteria that provide protection. It's basic symbiosis. 

I won't go into detail about what this could mean. Again I'm just brainstorming. But to western civilisations there is increasing evidence that many of the most serious diseases have a bacterial or viral link. So our propensity to travel that increases our exposure to every disease there is now seems like a serious liablity for which we have developed few defences. 

Coupled with our busy lives, high levels of stress, propensity to work indoors in warm inviting areas mayeb these are just a few of the reasons that could effectivly nurture diseases in western regions.