I work in a hospital laboratory and see peps that are sick from pools. The reason you don’t hear about it is because the environmental source of infections are hard to identify. I would venture most middle and outer ear, eye infections, and wound infections in families with pools are pool related. I have seen skin infections caused by Pseudomonas from pools. I have seen respiratory infections form pools and spas. I read an article a few days ago about pathogenic E.Coli transmitted by pool water. Its there you just don’t hear of it very much. I feel that if you are seeing algae you have a higher risk from pathogens in the pool as well. If our immune systems are functioning well we can fight off mild attacks but in the young and elderly populations are at higher risk.
Steve