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Are Swimming Pools Safe from Amoebic Meningitis Infection? : All You Need To Know

Medically reviewed by Regina Victoria Boyles, MD · Pediatrics

Written by Fiel Tugade · Updated May 06, 2022

    Are Swimming Pools Safe from Amoebic Meningitis Infection? : All You Need To Know

    Amoebic Meningitis, or also known as Primary Amoebic Meningoencephalitis (PAM), is a dangerous brain inflammatory disease. The infection is brought about by a specific type of free- living amoeba called the Naegleria fowleri.

    Naegleria fowleri, a “brain eating amoeba,” develops in warm, stagnant water such as lakes and rivers with temperature at 25°C – 40°C. Swimming pools which are not chlorinated adequately and spas that are not regularly cleaned may also cause the growth of this particular amoeba.

    Amoebic meningitis cases are common in children and young adults. The amoeba can enter their central nervous system through the nose when they swim in contaminated water. When it reaches the brain, it causes infections and tissue destruction, leading to death in most cases that show severe symptoms. However, a person cannot get PAM from swallowing infected water.

    Differentiating Amoebic Meningitis Cases

    There are also other types of amoebic meningitis that are caused by different amoebas. Primary amoebic meningoencephalitis (PAM) differs from another known type, granulomatous amoebic encephalitis (GAE). GAE is another fatal infection that is caused by the species Balamuthia and Acanthamoeba, which commonly enter through the skin and lungs.

    GAE is a type of amebic encephalitis that affects persons who have a weaker immune system or are already in poor condition. It advances more slowly in comparison to PAM.

    Signs and Symptoms  

    The initial symptoms of amoebic meningitis cases are somewhat similar to that of bacterial meningitis. Common symptoms typically show 1-9 days after the infection and it includes:

    • Severe headache
    • Fever
    • Nausea and vomiting
    • Meningeal irritation (that often leads to neck stiffness and sensitivity to bright light)

    Other signs that may later on be presented are:

    • Lethargy (dullness or inactivity)
    • Dizziness and confusion 
    • Loss of balance
    • Visual disturbances
    • Seizures
    • Hallucinations
    • Altered mental status and other abnormalities
    • Coma

    Some may also experience signs that involve the nose like lack of smell (or even taste).  nasal obstruction and discharge.

    A person’s condition progresses rapidly after the onset of these symptoms. It typically leads to death within 3 to 7 days. 

    Sources and Other Risk Factors

    Exposure to such areas may lead a person to have the Naegleria infection.

    • Hot springs
    • Water heaters
    • Soil
    • Bodies of warm freshwater like lakes and rivers
    • Untreated geothermal sources of drinking water
    • Discharge of warm water from industrial plants
    • Poorly-maintained swimming pools


    Amoebic meningitis cases are non-communicative. The infection does transfer or spread from one person to another because they may have come in close contact. 


    Amoebic meningitis cases are actually difficult to diagnose as its early stages of symptoms are not specific enough to consider its possibility. Doctors may ask the patient whether he or she has had exposure to any of the risk factors. However, it may be hard to detect if the amoeba is already present in the body. 

    A doctor may perform a spinal tap to collect a sample of cerebrospinal fluid (a fluid surrounding the brain and spinal cord) and analyze it. Another method of diagnosis would be examining the brain or even the skin through a biopsy in order to rule other possible causes of brain infection. 

    Specialized laboratories may offer other techniques and processes available that could detect the presence of amoebas.

    • Culturing and growing microorganisms until their number is sufficient for identification 
    • Processing a polymerase chain reaction (PCR) to check the amoeba’s genetic material
    • Conducting a brain biopsy that is stained and studied under a microscope, or that is tested via PCR or via immunohistochemistry

    Key Takeaways

    Amoebic meningitis cases are as life-threatening as it can be. If you suspect yourself to be feeling few symptoms with an exposure to a swimming gathering that may have contaminated water, then you should seek medical care immediately before it gets worse.

    Learn more about meningitis, here.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Medically reviewed by

    Regina Victoria Boyles, MD


    Written by Fiel Tugade · Updated May 06, 2022

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