Naegleria Fowleri: The “Brain-Eating Amoeba”
South Korea has recently reported its first case of infection from the Naegleria fowleri amoeba, also known as the “brain-eating amoeba”. The infected individual, a 50-year-old Korean national who had recently returned from Thailand, died 10 days after showing symptoms of the rare yet fatal infection.
What is Naegleria fowleri?
Naegleria is a single-celled organism, or amoeba, and only one of its species, called Naegleria fowleri, can infect humans. It was first discovered in Australia in 1965 and is commonly found in warm freshwater bodies such as hot springs, rivers, and lakes.
How does it infect humans?
The amoeba enters the human body through the nose and then travels up to the brain. This can usually occur when someone goes swimming, diving, or even when they dip their head in a freshwater body. In some cases, it has been found that people can get infected when they clean their nostrils with contaminated water. However, there is no evidence of the amoeba spreading through water vapor or aerosol droplets.
Once the amoeba reaches the brain, it destroys brain tissue and causes a dangerous infection known as primary amoebic meninges encephalitis (PAM).
What are the symptoms of PAM?
The initial symptoms of PAM can appear within one to 12 days after the infection and may be similar to meningitis, including headache, nausea, and fever. In later stages, one may experience a stiff neck, seizures, hallucinations, and even coma. The infection spreads rapidly and on average causes death within about five days. The fatality rate of PAM is such that only four people out of 154 known infected individuals in the United States from 1962 to 2021 have survived, according to the US Centres for Disease Control and Prevention (CDC).
What is the treatment for the infection?
Due to the rarity and rapid progression of the Naegleria fowleri infection, there is currently no effective treatment. Doctors typically treat it with a combination of drugs including amphotericin B, azithromycin, fluconazole, rifampin, miltefosine, and dexamethasone.
Can climate change increase the spread of the infection?
According to the CDC, the chances of getting a Naegleria fowleri infection may increase with rising global temperatures as the amoeba thrives in warm freshwater bodies. The amoeba grows best at temperatures up to 46’C and can sometimes survive at even higher temperatures. Several recent studies have found that excess atmospheric carbon dioxide has led to an increase in the temperature of lakes and rivers, providing a more favourable environment for the amoeba to grow. Heatwaves, when air and water temperatures may be higher than usual, may also allow the amoeba to thrive. The CDC also notes that while infections were initially mostly reported in southern states in the US, in recent years they have been seen in northern states as well. Naegleria fowleri has been found in all continents and has been declared as the cause of PAM in over 16 countries, including India.
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