All You Need to Know About 'Brain-Eating Amoeba' as First Death Confirmed in South Korea

Naegleria fowleri, known as the “brain-eating amoeba," which can be found in soil and warm fresh water, such as lakes, rivers, and hot springs, has claimed its first victim in South Korea.

The man - a South Korean national said to be in his 50s - died after returning to the country on December 10 from Thailand, where he had spent four months, according to the Korea Disease Control and Prevention Agency (KDCA). The man was admitted to a hospital the day after his return, experiencing symptoms that included a headache, fever, vomiting, speech dysfunction, and others. He died on December 21.

After carrying out genetic tests on three types of pathogens causing Naegleria fowleri, on Monday, the KDCA confirmed the infection in a deceased patient with brain meningitis, who had "recently returned from abroad."

People in the country were also strongly advised to take precautions against the culprit, such as placing special clips on their noses when swimming to prevent water from entering.

Since 2018, around 381 cases of Naegleria fowleri have been reported on a global scale, including in Thailand, India, the United States, Japan, and China.

A species of the genus Naegleria, the single-cell organism called Naegleria fowleri is a type of amoeba particularly tailored to inhabiting warm freshwater and soil. Its preferred habitat, where it enjoys its highest reproductive rate, is a warm water environment characterized by a temperature of around 115 F (46.11 degrees Celsius.) It can be found in lakes, rivers, and geothermal hot springs. The culprit causing the rare, but often fatal infection can frequent warm water discharge from industrial or power plants, poorly maintained (minimally chlorinated) swimming pools, and water heaters. The unicellular organism can also live in damp soil, but Naegleria fowleri is not found in salt water, such as the sea.

When water temperatures fall below 77°F (25°C), the microorganism is less likely to thrive. In colder temperatures, the amoeba typically falls into a dormant state. However, it does not die, and is able to survive as it lies buried in the sediment of a body of water.

In the case of human infections, the free-living thermophilic amoeba travels up through the nose via the nasal mucosa during water activities, especially involving diving. This can also happen when people cleanse their noses or irrigate their sinuses using contaminated water. The amoeba is thus able to reach up towards the cerebrospinal fluid (CSF) and brain.

There have not been any documented cases of infection via the drinking of contaminated water. As the amoeba travels up the nose to the brain and spinal cord, it devours erythrocytes, also called red blood cells, and nerve cells. Thus, it causes inflammation and destruction to the brain tissue, triggering the rare and very severe disease called primary amoebic meningoencephalitis (PAM). Neither the amoeba itself nor the disease it is fraught with can be spread by people via human contact.

About five days after infection, the first symptoms of PAM usually start to manifest themselves. However, in some cases, the symptoms begin to emerge as early as one day after exposure, or as late as about 12 days after contamination. Symptoms may include a severe headache, feverish chills, nausea, or vomiting. Further on, the symptoms may also include a stiff neck, disorientated state, seizures and hallucinations, and, subsequently, a coma.

Brought on by the free-living amoeba Naegleria fowleri, primary amebic meningoencephalitis (PAM) is a disease that affects the central nervous system. PAM almost always results in a fatal outcome, with the death rate estimated at over 97 percent. Out of a recorded 154 people who suffered from the disease triggered by the microorganism in the United States from 1962 to 2021, only four individuals are known to have survived the ordeal.

Besides watching out for the warning symptoms, PAM can be diagnosed in a laboratory by microscopic examination of the cerebrospinal fluid (CSF) or brain tissue to detect Naegleria fowleri organisms.

As for treatment, a combination of medications to control inflammation are typically used, such as amphotericin B, azithromycin, fluconazole, rifampin, miltefosine, and dexamethasone, according to the US Centers for Disease Control and Prevention (CDC)

In order to avoid being infected with the disease that the amoeba sets off, it is generally recommended that people steer clear of swimming in untreated freshwater, particularly during warm months. As diving renders one susceptible to such exposure, individuals are advised to use nose plugs or clips, along with face masks. Furthermore, water with a chlorine level above 0.5mg/L also has been known to decrease risk of N. fowleri. Similarly, one should avoid contact with soil or mud possibly contaminated with the "brain-eating" amoeba.

According to the CDC, the three confirmed Naegleria fowleri cases in the United States in 2022 occurred after exposure to bodies of freshwater in Iowa, Nebraska, and Arizona.