How does a person get infected by the brain eating amoeba?

Mostly people get infected while swimming or diving in warm lakes, rivers, or ponds. It can also happen if someone uses unboiled tap water in a neti pot or for nasal cleansing. So the key risk factor is water entering the nose.

Infection happens only if water containing the amoeba goes up your nose. From there, it travels through the olfactory nerve into the brain. You cannot get infected by drinking contaminated water. This is a common myth. It only happens through nasal exposure.

Some rare cases are reported from water parks or even poorly chlorinated pools. But in general, treated and disinfected water is safe. The infection route is very specific and does not spread from person to person.