"Once the amoeba reaches the brain, it begins destroying brain tissue and causes a devastating infection called primary amoebic meningoencephalitis, which is usually fatal."
"The amoebae[...]destroy brain tissue by releasing toxic molecules," Halston said."The immune system tries to fight the infection by sending immune cells and fluid to the brain. The combination of the toxic molecules and the immune response causes brain swelling and death." Symptoms usually appear around 12 days after infection, with death following within days. The fatality rate forinfections is so high due to the rate that the amoeba reproduces inside the body, and its efficacy at destroying the brain.
"The infected person has no specific, pre-existing defense methods to the amoebae, so they are unable to contain the infection on their own," Bobbi Pritt, director of the clinical parasitology laboratory at the Mayo Clinic, previously told"In the rare instances where people survived, it was because the infection was diagnosed early on, before much damage was done, and they were treated very aggressively.
"The survivors reported to date in the United States were treated with multiple drugs to kill the amoebae, and with therapeutic hypothermia to reduce brain swelling."CDC map of primary amebic meningoencephalitis caused by Naegleria fowleri in the United States between 1962–2022.