Ok – I confess. There’s only one reason this parasite is sci-fi worthy. Though, to be fair, it’s a pretty good one: it kills you by eating your brains! :O
Meet Naegleria fowleri. A happy, free-living protist that lives in warm fresh water – at least until a very unlucky person dunks their head in it.
Naegleria fowleri is technically not ‘a’ brain amoeba so much as the ‘PREMIER’ brain amoeba of record. Like most amoebas, it basically goes through life as a single-celled sack of fluid gelatin surrounded by a greasy membrane. This Amoeba lives mostly in freshwater lakes and ponds and at times, is found in heated swimming pools following transfer through bird waste or vector insects. By encapsulating themselves into cysts, brain amoebas can endure harsh environmental conditions such as drying or extreme cold, essentially allowing them to lie dormant anywhere at anytime.
Naegleria has three stages of its life: a flagellate, and amoeba, and a cyst. In the water, it is in its infectious, flagellate form called a “trophozoite”. It reproduces asexually, and swims around quite happily if the water is fresh and warm (over 75 degrees). If conditions are poor, the little amoeba will encyst, creating a round, hard casing which survives extreme conditions. When conditions become better, it reverts in minutes back to its happy, flagellated self.
But, of course, they’re even happier when a person sticks their head under that nice, warm water. The trophozoite swims up the nasal cavity and enters the olfactory mucosa and nasal tissues. At first, this just destroys the person’s olfactory bulbs. But the parasite isn’t done yet – it travels along the nerve fibers through to the brain itself. It sheds its flagellum and switches to its amoeba stage – a slow, single-celled organism that divides like crazy. If returned to the water somehow, it would switch right back to having a flagellum. But in the meantime it divides, creating a colony of amoebas in your brain.
Infection with Naegleria causes the disease primary amoebic meningoencephalitis. The Brain is a VERY HARD organ for pathogens to access. But the Brain Amoeba uses it’s enzymes as a fake ID to get past the blood-brain barrier and now as it enters the club, the real fun begins.
Part of the disease is caused by the parasite’s mere presence and the body’s immune reaction to it. Most of the damage is caused by the amoebas chowing down on the neurons themselves. Naegleria have special surface proteins which act like a chain saw, cutting holes in the neuron’s cellular membranes. As the contents of these neuron cells leak out, the amoeba grabs all the nutrients it can stuff into it’s membrane; quickly converting human memories and neurological functions into holes filled with plasma, nitrogen waste and more Brain Amoebas!!! :O
At first, changes in sense of taste or smell or severe nasal infections are the only warning of the sinister parasite lurking within. These are followed by symptoms similar to bacterial meningitis – fever, stiff neck, etc. As time wears on, usually 1-3 days later, someone infected with Naegleria might be easily confused, lose ability to focus, lose their balance, have seizures and even hallucinate. Death almost always follows within 3-7 days.
Mortality rate of N. fowleri infection stands at 97 percent, with infected corpses garnering extra crematorium expenses to destroy encysted amoebas and amoebas freely leaking out the ears and nose to search for new sources of food.
Of the ‘lucky‘ 3 percent who survive the onslaught of the Brain Amoeba, few will ever be fully functional again… 😦
Cures to Naegleria haven’t been developed yet, as it has the nasty habit of changing its protein coat whenever something targets it. That’s how it evades the immune system, too – that, and it can steal proteins that it eats to place on its membrane, essentially fooling the immune cells into believing its one of our own cells. That, and of course, how quickly people die from it. But, luckily, infections are fairly rare, despite how widely-dispersed and common the parasite is. Part of this is likely due to the fact that it can’t be spread person-to-person directly… yet.
The parasite thrives when the temperature heats up – preferring a nice, steaming bath of around 95 degrees. It’s no surprise, then, that infections are most common in the summer months. It does make you think, though – if temperatures start to rise throughout the world, will Naegleria infections rise, too?
That’s the last thing we need – more zombie-wannabe amoebas. Now if that’s not incentive to cut carbon emissions, I don’t know what is!!!
Naegleria fowleri is found around the world. In the United States, it has caused infections in 15 southern tier states (AR, AZ, CA, FL, GA, LA, MO, MS, NC, NM, NV, OK, SC, TX, and VA).
😉 😉 Basically, keep your head in salt water OR above the Mason-Dixon line 😉 – You’ll be fine!!! 😉 😉
The amoeba grows best in warm or hot water. Most commonly, the ameoba may be found in:
- Bodies of warm freshwater, such as lakes, rivers
- Geothermal (naturally hot) water such as hot springs
- Geothermal (naturally hot) drinking water sources
- Warm water discharge from industrial plants
- Poorly maintained and minimally-chlorinated or unchlorinated swimming pools
*Naegleria is not found in salt water locations*
***Not everyone exposed to N. fowleri amoebas will become infected. Only one in every 2.6 million exposures to the amoeba leads to infection. ***
The Centers for Disease Control and Prevention suggests that the following measures may reduce your risk of naegleria infection:
- Don’t swim or jump into warm bodies of fresh water such as lakes, rivers, hot springs and polluted water around power plants.
- Don’t swim or jump into fresh water during periods of high temperatures and low water volume.
- Hold your nose shut or use nose clips when jumping or diving into warm bodies of fresh water.
- Avoid disturbing the sediment while swimming in shallow, warm fresh waters.
- Don’t swim in posted “No swimming” areas or in areas where there are warnings of increased naegleria-infection risk.