What is a brain-eating amoeba? First infection reported in South Korea

The amoeba is found not only in warm fresh water, such as ponds, lakes, rivers and hot springs, it is also found in the soil near warm water discharges of industrial plants and in unchlorinated or minimally-chlorinated swimming pools.

Seoul, Dec 27: South Korea reported its first case of infection from Naegleria fowleri or 'brain-eating amoeba' on Monday. Authorities confirmed that a Korean national died after 10 days of displaying symptoms of the rare but highly lethal infection.

Even though extremely rare - only 380 cases recorded worldwide since 1965, primary amoebic meningoencephalitis or PAM struck a 50-year-old man in Korea earlier this month. Going by the reports, the man returned to Korea on December 10 after a four-month long stay in Thailand and was admitted to a hospital the next day.

The patient began to show symptoms of meningitis, such as headaches, fever, vomiting, slurred speech and stiffness of the neck on the evening of his arrival, and was transferred to an emergency room the next day. He died on Dec 21, as reported by The Korea Times.

After he was pronounced dead, health authorities conducted further tests to confirm the exact cause of death, which was found to be a Naegleria fowleri infection. This is the first known infection from the disease in the country. In the United States, only four out of 151 total known infected individuals have survived as of 2020.

The Korea Disease Control and Prevention Agency (KDCA) is yet to discover the exact route of transmission, but noted that swimming in contaminated water or nasal rinsing with unsafe water are the leading causes of infection.

What is Naegleria fowleri?

Also known as the 'brain-eating amoeba', is a species of the genus Naegleria, belonging to the phylum Percolozoa, which is technically not classified as true amoeba, but a shapeshifting amoeboflagellate excavata. It is a free-living, bacteria-eating microorganism that can be pathogenic, causing a sudden and severe and fatal brain infection called naegleriasis, also known as primary amoebic meningoencephalitis.

It is commonly found in warm fresh water, such as ponds, lakes, rivers and hot springs. It is also found in the soil near warm-water discharges of industrial plants and in unchlorinated or minimally-chlorinated swimming pools.

It can enter the human body through the nose, makes its way to the brain and causes PAM. In the brain, it feeds on nerve tissues and multiplies, causing necrosis and bleeding. The fatality rate exceeds 97 percent, but the infection does not spread between humans.

Generally beginning within two to 15 days of exposure to the amoeba, signs and symptoms of naegleria infection may include:

• A change in the sense of smell or taste
• Fever
• Sudden, severe headache
• Stiff neck
• Sensitivity to light
• Nausea and vomiting
• Confusion
• Loss of balance
• Sleepiness
• Seizures
• Hallucinations

These signs and symptoms can progress rapidly. They typically lead to death within a week's time.

Treatment

The core antimicrobial treatment consists of antifungal drug amphotericin B, which inhibits the pathogen by binding to its cell membrane sterols, thus leading to cell membrane disruption and pathogen death. Miltefosine, an antiparasitic drug which inhibits the pathogen via disrupting its cell survival signal pathway PI3K/Akt/mTOR, has been used in a few cases with mixed results.