My parents have never been sick either, and I've never picked anything up when I used to not treat my water. My point in every single one of these conversations is that while I (and you and my parents and so on) have never been sick, I don't relish the opportunity to fight off giardiasis or any of the other fun bugs that are out there. 10-15 minutes of filtering a day and I don't have to worry about it. Why take that risk if you don't have to?
I agree completely.
I have two friends, married to each other, who own a camping outfitter. About 15 years ago, they were camping in Northern Algonquin Park. The wife had her filter on the front of her Canoe, but decided 3 minutes of pumping was too long. So she filled her bottle right from the lake. The logic, was that they were in the centre of a deep lake, that was crystal clear. Since most things in water, are heavier than water, they eventually sink to the bottom, meaning that the centre of a deep lake is often the cleanest.
She was in the hospital for 8 months, she lost 20% of her body weight and 10% of her bone marrow. The virus (whose name is lost to me at this time), was so destructive, that her internal organs are still damaged beyond repair. She can only eat certain things now, and is constantly seeing a nutritionist.
I have had Giardia, aka Beaver Fever. Not a fun thing.
I carry an MSR Sweetwater filter, with their Viral-stop droplets. I also carry the Pur-tabs from Katadyn. Besides that, I put my bandana across the mouth of my billycan, and strain the water through that, then boil it.