The Naegleria fowleri amoeba, commonly known as the “brain-eating amoeba,” is a type of single-celled amoeba that can be highly lethal, according to health organizations.
Although CDC records indicate that infections are not that frequent, cases have been fatal with a mortality rate of over 97 percent.
Of the 151 people infected in the United States between 1962 and 2020, only four survived, the CDC website describes.
What is the “brain-eating” amoeba?
According to the Centers for Disease Control and Prevention (CDC), the “brain-eating amoeba” is capable of causing a rare, life-threatening infection of the human brain called primary amebic meningoencephalitis (PAM).
Although Naegleria is an organism commonly found in warm freshwater such as lakes, rivers, and hot springs, as well as in soil, only the species Naegleria fowleri infects people with the disease.
Although Naegleria fowleri is found worldwide, most infections from the bacteria found in freshwater have been reported in the United States.
The amoeba can be found in these places:
- Temperate freshwater environments, such as lakes and rivers.
- Natural hot springs with warm geothermal waters.
- Discharges of moderate temperature wastewater from industrial facilities.
- Naturally warm geothermal drinking water supplies.
- Poorly maintained pools with minimal or no chlorine treatment.
- Water heaters, such as Naegleria fowleri thrive especially in high temperatures, reaching up to 115°F (46°C), and can survive for short periods at even higher temperatures.
- Land
- It is not found in saltwater environments, such as oceans.
How does brain-eating amoeba infection occur?
Infection occurs when water containing the amoeba Naegleria fowleri enters the body through the nose.
According to the CDC, this usually happens when people go swimming or diving in warm freshwater places, such as lakes or rivers, but it has also happened in patients who rinsed their noses with tap water.
Once the Naegleria fowleri amoeba enters the nose, it then travels up to the brain where it destroys brain tissue.
One point that the CDC clarifies is that it is not possible to become infected with Naegleria fowleri by drinking contaminated water. Nor has it been observed that it is transferred by water vapor or suspended droplets such as steam from a shower or steam from a humidifier.
Very rarely, Naegleria infections have occurred from contaminated water from other sources such as inadequately chlorinated pool water or contaminated tap water.
It is a heat-loving microbe and grows best at high temperatures up to 115°F (46°C). When temperatures drop, it is less likely to be found in water.
Brain-eating amoeba: Symptoms
The early symptoms of primary amebic meningoencephalitis (PAM), a disease caused by infection with Naegleria fowleri, may resemble those of bacterial meningitis.
The first signs of MAP usually appear between 1 and 7 days after infection and may include headache, fever, nausea, or vomiting.
Over time, symptoms may progress to neck stiffness, confusion, inattention to surroundings, loss of balance, seizures, and hallucinations.
Once symptoms appear, the disease develops rapidly and, in most cases, leads to death within 1 to 12 days.
Evolution of symptoms of the “brain-eating” amoeba
Initial symptoms, within the first 7 days, may include:
- Headache
- Fever
- Nausea and vomiting
Between 5 and 7 days after the illness, the symptoms evolve and the following may occur:
- Stiff neck
- Confusion
- Lack of attention to the environment
- Loss of balance
- Seizures and hallucinations