- People can't be infected with the amoeba by swallowing contaminated water.
- Ongoing heat and droughts could put more people at risk.
- The organism travels from the nose to the brain.
The brain-eating amoeba that killed three people this summer is an organism that thrives in warm fresh water and can be found in lakes, rivers, hot springs and soil, according to the Centers for Disease Control and Prevention.
All three deaths this year occurred in the South: a 16-year-old girl in Florida, a 9-year-old boy in Virginia and a 20-year-old man in Louisiana.
A brutal summer and drought make the conditions perfect for the amoeba. The threat of N. fowleri could potentially be elevated for weeks in some areas. According to the CDC, infections occur mainly in July, August and September.
The microscopic amoeba, Naegleria fowleri, attacks anyone who has the misfortune of inhaling it. It enters first up the nose and then goes to the brain, usually killing its victims within two weeks.
"Once forced up the nose, it can travel to the brain, where it digests brain cells," Jonathan Yoder, an epidemiologist at the Centers for Disease Control and Prevention, told Discovery News. "It's a very tragic disease that thankfully is very rare."
Aside from its rarity, the amoeba "is not looking to prey upon human victims," he said. "They usually go after bacteria in water and soil."
As single-celled organisms, amoebas do not even have brains. However, Naegleria species, including this disease-causing one, can transform themselves into three different basic "body" types.
"This one-celled organism hunts and eats bacteria as an amoeba, swims around looking for a better environment as a flagellate, and then hunkers down and waits for good times as a cyst," said Simon Prochnik, a computational scientist at the U.S. Department of Energy's Joint Genome Institute. "It is a very rare process to go from amoeba to flagellate like this."
Prochnik, who sequenced the genome of a Naegleria species last year, explained that when environmental conditions are not favorable, the "stressed" amoeba can quickly grow two tails, transforming it into the flagellate. It can then swim and move around to a better spot, similar to the way that human sperm travel.
To support these three body or "personality" types, as Prochnik calls them, the organism is packed with genes: 15,727 of them. To put that into perspective, humans have 23,000 protein-coding genes.