It kills much more than 97% of its victims. Just four world in the united state have ever survived it.

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Beth Mole - Jul 26, 2019 6:25 pm UTC


A 59-year-old phibìc Carolina man passed away Monday, July 22, from an infection brought about by the free-living amoeba Naegleria fowleri, aka the “brain-eating amoeba.”

According come state officials, the man fell victim come the single-celled organism after swim at the Fantasy Lake Water Park in Cumberland county on July 12, 2019. Laboratory experimentation at the Centers for an illness Control and also Prevention later evidenced the infection. Despite N. Fowleri room rare, they’re almost always deadly, which has actually health officials calling for higher awareness.

"Our sympathies are with the family and also loved ones," NC State Epidemiologist Zack Moore, MD stated in a statement. "People should be conscious that this biology is existing in warmth freshwater lakes, rivers and also hot springs throughout North Carolina, so it is in mindful together you swim or reap water sports."

Profile that a killer

N. Fowleri is a heat-loving amoeba, well-known for to mark swimmers during sweltering summer temperature (it prefers temps up to 115°F/46°C). However, the wee critter is actually ubiquitous in the environment and also distributed worldwide. That hangs the end in every kinds that soils and also freshwaters, surfacing not just in lakes, rivers, and geothermal waters, however in industrial cooling ponds, poorly-kept swim pools, and also domestic water pipelines warmed in the sun. Worldwide, that often uncovered in tropical areas but has actually infected people in the Czech Republic, new Zealand, Belgium, and also Japan. In the US, the most frequently kills in southerly states, however the amoeba has popped increase in states such together Minnesota and also Indiana.


Enlarge / states where situations of Naegleria fowleri have actually occurred. N=145; state the exposure unknown for 4 cases. Map does not snapshot 1 instance from the U.S. Virgin Islands.

Still, it’s only in very details circumstances that N. Fowleri turns deadly come humans. In fact, between 1962 and 2018, us officials have actually only caught it infecting people in 145 cases, regardless of its prevalence in the environment. Worldwide, there’s only been approximately 300 or so situations in that time frame.

A vast majority of the time, N. Fowleri isn’t a savage microorganism but a humble protist quietly grazing ~ above bacteria and also yeast cells that cross that is path. This low-key way of living only appears to readjust when N. Fowleri somehow gets flushed straight into a person nose. This tends to take place when world are in splashy water parks, jet-skiing, or irrigating your sinuses with tap water that hasn’t been disinfected, boiled, or filtered. No other way of exposure it seems ~ to reason trouble; inadvertently swallowing N. Fowleri is harmless, for instance. However in a nose, things acquire ugly.


When N. Fowleri finds itself shoved right into a schnoz, it gets its footing by gripping the mucus membrane in the sleep passage. It climate heads deeper, inching along olfactory nerves as if go on a tight-rope come the brain (these nerves transmits intake from odor receptors in the nose to the brain.) But, before it makes it come the brain, it needs to slip with the cribriform plate, a grooved bone in ~ the roof that the sleep passages that enables passage the the olfactory nerves v tiny holes. The cribriform plate often tends to be much more porous in children and also young adults—who additionally appear come be much more susceptible come N. Fowleri. Of the 145 known cases in the US, 121 of castle (85%) to be in children and teens.

Whiff that doom

Once with the plate, N. Fowleri gets into the olfactory bulb—the framework in the forebrain involved in smell. There, every hell division loose. The immune system swiftly incomes war when it detects an invader within the central nervous system. N. Fowleri, meanwhile, goes back to grazing together it usually does in soils and water. But, of course, its meals are no longer eco-friendly bacteria and also yeast cells, rather they"re immune cell and brain tissue.

To feed, N. Fowleri uses devoted structures top top the surface of its cabinet body, referred to as simply “food-cups.” These are suction-cup like functions that ensnare and also absorb food. The protist likewise oozes enzymes the burst and destroy person cells and also nerves.


Enlarge / (a) transmission electron micrograph (TEM) of Naegleria fowleri trophozoites illustrating the significant nucleus v a centrally situated electron-dense nucleolus. (b) Scanning electron micrograph (SEM) of trophozoites exhibiting ‘food-cups’ (arrow).
Marciano-Cabral & Cabral, 2007

The combination of a feasting amoeba and also a blizzard of immune responses leads to significant tissue and nerve damage, and also ultimately—most the the time—death. The problem is referred to as PAM, major amebic meningoencephalitis.

For the PAM victims, the start of the onslaught is significant by a significant headache, fever, chills, and sometimes nausea and also vomiting, usually anywhere from one to nine days after an exposure. The symptoms development to those checked out in meningitis, such as stiffness in the neck and also hamstrings, and also sensitivity to light, confusion, seizures, and coma.

Because there space so few cases that PAM, researcher haven’t been able come conduct any kind of trials to number out which medicine or medicine cocktails job-related best against the amoeba. Treating doctors often use huge mixes that antibiotics and also antifungal drugs.


One of the most usual treatments is amphotericin B, one antifungal drug that has proven lethal come N. Fowleri in laboratory studies but has use-limiting toxic impacts on the kidneys. The broad-spectrum antimicrobial miltefosine has additionally shown promise in some cases. It was originally emerged to tackle chest cancer, yet the drug came to be the leading alternative to treat an additional parasitic infection, leishmaniasis.

Lucky ones

Worldwide over there are just a handful of cases of people surviving PAM. Five well-documented instances have emerged in phibìc American: four in the US, and also one in Mexico.

The first survivor to be a 9-year-old girl who fell ill in 1978. She was properly treated with amphotericin B, but subsequent rap tests argued that the invading amoeba was less virulent than various other strains that N. Fowleri. Next was the 2004 report of a survivor in Mexico—a 10-year-old boy fell ill after swim in an irrigation canal and also recovered ~ a cocktail that consisted of amphotericin B.

The us went 35 years without one more survivor. In 2013, two youngsters survived, however they had different treatments and outcomes. The first was a 12-year-old girl exposed in ~ a water park in small Rock, Arkansas. Her symptoms were spotted quickly and she to be diagnosed within 30 hours. Doctors automatically started her on a huge cocktail that drugs including amphotericin B and miltefosine. They likewise used medically-induced hypothermia to minimize her brain swelling. The girl make a complete recovery.

The 2nd survivor in 2013—an 8-year-old boy—was additionally treated with a huge cocktail the drugs consisting of amphotericin B and miltefosine. However he was diagnosed and treated only after work of symptoms. He survived yet suffered what is most likely permanent brain damage.

The fourth and also final survivor was 16-year-old young infected in the summer the 2016. He to be diagnosed quickly and also got the same treatment as the 12-year-old girl. He, too, made a full recovery.

The situations offer expect that someday all PAM victim will have the ability to be treated and also saved. But, v a less than 3% survive rate currently in the US, it’s ideal to shot to avoid obtaining infected in the very first place.


To avoid acquiring a brain-eating amoeba if swimming, experts recommend trying come avoid warmth freshwater sources as soon as possible, opting for well-chlorinated pools and also saltwater instead. If you execute swim in warm freshwater, shot to minimize jumping, splashing, and dunking. Plug her nose, or use a nose clip come avoid getting water in her nasal passages. Also avoid stirring up sediment in shallow waters.

For sinus rinsing, the CDC recommends making use of store-bought distilled water, boiled insanity water, or water filtered v pore sizes one micron or smaller (the labels typically include “NSF 53” or “NSF 58” or save the indigenous “cyst removal” or “cyst reduction”).

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Enlarge / Naegleria fowleri has 3 step in the life cycle: cyst (1), trophozoite (2), and flagellate (3). The only infective stage of the ameba is the trophozoite, the other two stages are to address unfavorable ecological conditions. Trophozoites room 10-35 µm long with a granular appearance and a single nucleus. The trophozoites replicate by binary division during which the atom membrane remains undamaged (a process called promitosis) (4). Trophozoites infect humans or pets by penetrating the nasal tissue (5) and also migrating come the brain (6) via the olfactory nerves causing primary amebic meningoencephalitis (PAM).