Wild Animals and Water-Born Illnesses.

Factual Questions
1

True story. There is this river near where I live called the River Rouge. And it is so polluted, it would literally make you gag. It is supposed to be red (hence the name). But it is a murky green, since communities have been pouring so much of their waste and whatnot in it.

Anyways, I sometimes see animals drink from it and frolic in it. One time I was in a local park, by the river. And I saw something moving off in the distance, in the river. It was a rat swimming up the river, using its tail as a propeller! I almost lost my lunch right then and there. But the rat seemed unaffected by the dirty water. I know there is this story of this man who once accidentally fell in the River Rouge. He swallowed a few good mouth fulls of water too. And–true story–he shortly died. They say he died of this disease carried by wild animals, I seem to recall FYI.

My question is simply, How can wild animals drink water that would make a human sick? Cholera, Typhus, all kinds of water-born illnesses that humans would die from, but which wild animals (esp. birds, I’ve noticed) seem immune to. Well?

:):peace_symbol:

2

I think the question really ought to be: why are people, as opposed to wild animals, so sensitive to water-borne disease?

And the answer probably is: because we grew up in a protected environment, so our bodies never has had a chance to adapt to drinking contaminated water.

3

Most bacterial and viral diseases are species specific. e.g. cholera affects humans, not raccoons. Raccoons have their own host of diseases you can’t catch. Same story for all the other species.

Most water-bore illnesses affecting people are directly caused by dense populations of people peeing & pooping in the water they then try to drink. So we’re super-charging our own water with our own diseases.

Despite the proverbial bear always shitting in the woods, there is a lot more human shit in a village than there is bear shit in bear bearing woods. Hundreds of times more. So the humans make each other sick, whereas the bears don’t do the same to each other.

Folks who raise livestock have a similar problem. Farm animals kept in pastures or worse yet dense feed lots quickly foul the ground with all manner of parasites & diseases. Which must then be managed with drugs, selective breeding, pasture turnover, etc.

Bottom line: wild species’ populations simply don’t grow to the density necessary for water-borne illness to be a major factor. The competition for available food or predator pressure is a more limiting factor on population density.
So that’s disease. What about pollution, which is a totally different problem?

Water that’s loaded with oil, or heavy metals, say, is dangerous for us to drink because it’s full of substances poisonous to humans. Probably not instantly poisonous in most cases, but certainly injurious to long term health.

Why do you think that such pollution has a different effect on animals? Just because you saw one rat swimming one time doesn’t mean the local river water doesn’t sicken or kill most wildlife which spends much time in it.

And for rats, what’s the significance of being exposed to massive doses of, say, carcinogens when the vast majority are killed by predators in middle age or earlier before the cancer has time to grow? There would be almost zero impact on their population dynamics.

Bottom line on pollutants:

Most wild species operate this way: live fast, die young, and produce massive offspring to offset infant mortality & juvenile predation. In that scenario, quick-acting pollutants act like heavy predator pressure, depressing headcount but leaving the survivors apparently healthy (at least at casual first glance). And slow acting pollutants, e.g. carcinogens, have almost no impact at all since they only affect the animals in later post-reproductive life.

The individual pollution survivors may well be weakened, biochemically crippled, or otherwise miserable. But they’re still alive, which is all you can tell from a casual sighting of one swimming in the gunk.