Been reading about Naegleria Fowleri amoeba for a long time, but have never been able to find data on how long the amoeba is able to survive in the nasal passage prior to going into the brain. The quote everywhere is that the amoeba manifests symptoms within 0-2 weeks of entry into the nose, however, apparently it can also lurk in the nasal passage for a while before it actually makes the brain trip. Since it eats bacteria and likes warm temperatures, can it basically survive indefinitely inside your nose and sinus?
Something I’ve found interesting about this horrific disease is that its victims appear to almost always be adolescents - in other words, aged around 10 to 20. I do remember hearing about an adult victim, and a few younger children, but all the others were teenagers or thereabouts.
Sorry I don’t have the answer to your question.
Possibly a lot more adolescents swim for fun than adults?
Maybe, or they might be willing to swim in dirtier-looking water than their parents, who would also keep younger children out? Why dozens or hundreds of people pass through a beach or a swimming hole, and only one person gets sick is a mystery that demands (and is probably getting) more research.
I’d be interested if there is any data myself( been curious about this critter since the 1980’s ), but I’ll make an educated guess that given the scarcity of cases and an often delayed diagnosis there is no real answer. It’s just a vanishingly rare syndrome.
I believe the hypothesis about the emphasis on young victims is that it probably reflects the young being more involved in active diving/water-skiing forcing water into the nose at velocity and perhaps the more porous cribiform plate in younger folks being easier to penetrate.